tag:blogger.com,1999:blog-59637189181396472632024-02-07T06:05:10.397-08:00H I F I D U I N OARDUINO FOR HI-FIUnknownnoreply@blogger.comBlogger112125tag:blogger.com,1999:blog-5963718918139647263.post-76288151057087660632012-10-15T11:28:00.002-07:002013-01-07T17:18:42.907-08:00Register Address Values for OPUS code(I have corrected this post as to give the wrong impression)<br />
Having done further programming with the Buffalo DAC, I realized that the register address values I used for the OPUS code are pehaps wrongly coded in 8-bit format where the I2C protocol of the Arduino Wire library is based on 7-bit register addresses.<br />
<br />
The code as it is works with volume, oversampling filter selection and even filter choice, even though I can't tell the filters apart (but a high frequency test tone with young people proved that they can tell filters apart)<br />
<br />
This means that the OPUS DAC code for the WM8741, should be reviewed for the address value.Unknownnoreply@blogger.com2tag:blogger.com,1999:blog-5963718918139647263.post-85070673176898710572010-03-31T13:34:00.000-07:002011-01-23T18:47:07.837-08:00Continue reading HIFIDUINO...... at <a href="http://hifiduino.wordpress.com/">hifiduino.wordpress.com</a><br />
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<div style="clear: both; text-align: left;"></div>Unknownnoreply@blogger.com6tag:blogger.com,1999:blog-5963718918139647263.post-57412612078065033172010-03-20T18:08:00.000-07:002010-03-22T10:43:09.532-07:00Buffalo II DAC(Click to enlarge)<br />
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<div style="clear: both;"></div>More <a href="http://hifiduino.blogspot.com/2010/02/buffalo-ii-specification-and-faq.html">here</a>Unknownnoreply@blogger.com3tag:blogger.com,1999:blog-5963718918139647263.post-76818345773354237892010-03-15T18:19:00.000-07:002010-03-25T10:59:44.963-07:00Comparing Noise Figures in Linear RegulatorsJust like phase noise in clocks, it is difficult to compare noise values among linear regulators because there is no common ground in specifying noise figures. Some companies report noise density, others RMS V noise, and yet others % of Vout. The frequency range for the reported noise figures also varies from company to company.<br />
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The <a href="http://cds.linear.com/docs/Datasheet/1763ff.pdf">LT1763</a> familiy is a favorite for audio projects because it has low noise figures. Among linear regulators it is probably universally preferred by audio diy aficionados.<br />
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In order to compare other regulators to this benchmark device, I decided to calculate the Vrms noise in each of the fequency ranges provided by the chart. The Vrms noise is basically the product of the noise density times the frequency delta.<br />
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The results is shown in the graph below. Total Vrms = 23.2 uVrms for the frequency range 10Hz to 100KHz. This approximation is very close to the specified value of 20 uVrms.<br />
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I then looked as the specified noise of several common regulators and matched the values to the corresponding value of the LT1763 device.<br />
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A couple of observations: The <a href="http://www.national.com/ds/LM/LM340.pdf">LM340</a> is actually very good, in fact better than the beloved LM317 according to spec. The LM723 seems of lower noise than the LT1763, at least in the reported frequency range. <br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNwWk3M6qTMYS6dXOxIn8SoL_4G1sqLJroKaNgfHIMyec4V0bKqSfV82HHyfzUBEy5TZXKxAla0NMUpJxW1g3uPnIzQTWgn_t2HchoHz9Wr8kO38TeYo-bgGf7uFznIMnMWKFdIWXncYc/s1600-h/regnoisejpg.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNwWk3M6qTMYS6dXOxIn8SoL_4G1sqLJroKaNgfHIMyec4V0bKqSfV82HHyfzUBEy5TZXKxAla0NMUpJxW1g3uPnIzQTWgn_t2HchoHz9Wr8kO38TeYo-bgGf7uFznIMnMWKFdIWXncYc/s400/regnoisejpg.jpg" /></a><br />
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<div style="clear: both;">We can approximate the total noise Vrms for the 10Hz-100KHz interval by noticing that each frequency range contributes a percentage of the total noise. In the case of the LT1763, we notice that the 10Hz-10KHz range contributes about half of the total 10Hz-100KHz noise. The table below compares all the regulators in the 10Hz-100KHz range.</div><div style="clear: both;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgssf6fJwgBCW3Q-1DUGxXFE8Y26WEri-g_M08QZfrKLSaVuP1MHhRgBVNSH9RaG0yH5dRMst5mjIDiudY2v7u1es54gCBwei2KKOE0uihxfvalrvZgEsu6wLTsPO3FziilIKbxCcAhXLQ/s1600-h/regnoise2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgssf6fJwgBCW3Q-1DUGxXFE8Y26WEri-g_M08QZfrKLSaVuP1MHhRgBVNSH9RaG0yH5dRMst5mjIDiudY2v7u1es54gCBwei2KKOE0uihxfvalrvZgEsu6wLTsPO3FziilIKbxCcAhXLQ/s320/regnoise2.jpg" /></a></div><div style="clear: both;"><br />
Here is a very good paper from TI explaining noise in linear regulators: [<a href="http://focus.ti.com/lit/an/slyt201/slyt201.pdf">link</a>]<br />
According to the paper,<br />
<blockquote>"The dominant source of noise in an LDO is usually the<br />
bandgap. In most cases this is solved by adding a large<br />
low-pass filter (LPF) to the bandgap output so that none<br />
of the noise makes it into the gain stage."</blockquote>Unfortunately, it is not easy to access the bandgap output line in most integrated regulators...</div>Unknownnoreply@blogger.com6tag:blogger.com,1999:blog-5963718918139647263.post-51376334276014269132010-03-11T21:29:00.000-08:002011-09-02T17:44:34.402-07:00TPA's AC1 FAQNot an Arduino, but based on a cousin of the ATMega168 with built-in USB. Of course totally incompatible with the Arduino development tools. But if you are familiar with Arduino, you'd easily navigate this device.<br />
<br />
More pictures over at <a href="http://www.twistedpearaudio.com/forum/default.aspx?g=posts&m=5186">TPA's website</a><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6jY0HOp0kloGcGBQ0YUkMaxgUHMwt7fpX3ybxQsTvkxBClk2NkTNkM8kL6Komv5RZCMg2EoD7JDGdNzYFT2o4q95oYhMzA_xPSmCEV2b2WiSfGtmYtKSYFNwtQbAQitUWR0eHBZZ1WSo/s1600-h/DSC_0354.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6jY0HOp0kloGcGBQ0YUkMaxgUHMwt7fpX3ybxQsTvkxBClk2NkTNkM8kL6Komv5RZCMg2EoD7JDGdNzYFT2o4q95oYhMzA_xPSmCEV2b2WiSfGtmYtKSYFNwtQbAQitUWR0eHBZZ1WSo/s1600-h/DSC_0354.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6jY0HOp0kloGcGBQ0YUkMaxgUHMwt7fpX3ybxQsTvkxBClk2NkTNkM8kL6Komv5RZCMg2EoD7JDGdNzYFT2o4q95oYhMzA_xPSmCEV2b2WiSfGtmYtKSYFNwtQbAQitUWR0eHBZZ1WSo/s1600-h/DSC_0354.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="336" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6jY0HOp0kloGcGBQ0YUkMaxgUHMwt7fpX3ybxQsTvkxBClk2NkTNkM8kL6Komv5RZCMg2EoD7JDGdNzYFT2o4q95oYhMzA_xPSmCEV2b2WiSfGtmYtKSYFNwtQbAQitUWR0eHBZZ1WSo/s400/DSC_0354.JPG" width="400" /></a><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZ4-hcBZIloPYFnFa05cscsBhp5JA2GZjmBTCMNaptvzfhdxJls-wiBy6mcNPjKcp70hHGiaTo5nRUvZ5l9I2Kr8ipfR-m9oN2Jxt71Qm-bFUQbX6FLm8twNKIrW4LY8SuMbaWEmxOGHw/s1600-h/DSC_0356.JPG"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZ4-hcBZIloPYFnFa05cscsBhp5JA2GZjmBTCMNaptvzfhdxJls-wiBy6mcNPjKcp70hHGiaTo5nRUvZ5l9I2Kr8ipfR-m9oN2Jxt71Qm-bFUQbX6FLm8twNKIrW4LY8SuMbaWEmxOGHw/s400/DSC_0356.JPG" /> </a><br />
Instructions for loading (burning) firmware into FEMTO:<br />
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<ul></ul>1- Download and Install FLIP<br />
2- Copy libusb0.dll from usb directory to bin directory: copy the file C:\Program Files\Atmel\Flip 3.4.1\usb\libusb0.dll to C:\Program Files\Atmel\Flip 3.4.1\bin. Make sure you copy the file because it is needed on both directories<br />
3- Insert FEMTO and do the following sequence: <br />
a- Push HWD button<br />
b- Push RST button<br />
c- Release RST button<br />
d- Release HWD button<br />
4- At this point Windows will recognize the device ( FEMTO) and will guide you though the driver installation. 5- Select manual installation and you point the path to: C:\Program Files\Atmel\Flip 3.4.1\usb<br />
6- Start FLIP<br />
7- Start USB communication: Settings->Communication->USB<br />
8- Select device: Device-Select->AT90USB162<br />
9- Select hex file: File->Load Hex File->filename.hex<br />
10- Click Run<br />
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<ol></ol><br />
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<div style="clear: both;"></div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-5963718918139647263.post-63959409490957728382010-02-27T12:53:00.000-08:002010-10-12T06:52:14.338-07:00Programming Buffalo DAC: Review of Arduino I2C<div style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;"><span style="font-size: small;">Is is fairly simple to use Arduino to program a DAC such as the ESS Sabre32. After you connect the appropriate signals (wires) from Arduino to the Buffalo board, you follow the tutorial sketches (in Arduino the programs are called sketches) to set up the main code and use the Arduino I2C functions to write values into the registers of the DAC.</span></div><div style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;"><span style="font-size: small;"><br />
</span></div><div style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;"><span style="font-size: small;">In Arduino, the I2C protocol is supported by the "<a href="http://www.arduino.cc/en/Reference/Wire">Wire library</a>" and the functions are the following:</span></div><ul style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;"><li><span style="font-size: small;"><a class="wikilink" href="http://arduino.cc/en/Reference/WireBegin">begin</a>() - Join the I2C bus as a masterdevice</span></li>
<li><span style="font-size: small;"><a class="wikilink" href="http://arduino.cc/en/Reference/WireBegin">begin</a>(address) - Join the I2C bus as a slave device</span></li>
<li><span style="font-size: small;"><a class="wikilink" href="http://arduino.cc/en/Reference/WireRequestFrom">requestFrom</a>(address, count) - Tell device that a request will follow</span></li>
<li><span style="font-size: small;"><a class="wikilink" href="http://arduino.cc/en/Reference/WireBeginTransmission">beginTransmission</a>(address) - Tell device as address that data transmission will start </span></li>
<li><span style="font-size: small;"><a class="wikilink" href="http://arduino.cc/en/Reference/WireEndTransmission">endTransmission</a>()- Tell device that transmission is ended</span></li>
<li><span style="font-size: small;"><a class="wikilink" href="http://arduino.cc/en/Reference/WireSend">send</a>() - Send data (one byte at a time)</span></li>
<li><span style="font-size: small;">byte <a class="wikilink" href="http://arduino.cc/en/Reference/WireAvailable">available</a>() - Queries number of bytes available for retrieval</span></li>
<li><span style="font-size: small;">byte <a class="wikilink" href="http://arduino.cc/en/Reference/WireReceive">receive</a>() - Retrieve (read) bytes from device</span></li>
<li><span style="font-size: small;"><a class="wikilink" href="http://arduino.cc/en/Reference/WireOnReceive">onReceive</a>(handler) - The function to perform when slave receive a transmission</span></li>
<li><span style="font-size: small;"><a class="wikilink" href="http://arduino.cc/en/Reference/WireOnRequest">onRequest</a>(handler) - The function to perform when slave receives a request</span></li>
</ul><div style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;"><span style="font-size: small;">Before you do anything, Arduino joins the I2C bus as a master device with</span></div><blockquote><span style="font-size: x-small;"><span style="font-family: "Courier New",Courier,monospace;">begin()</span></span> </blockquote><div style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;"><span style="font-size: small;">The following code will write one value into one register:</span></div><br />
<span style="font-size: x-small;"><span style="font-family: "Courier New",Courier,monospace;">beginTransmission(0x80); // Address of DAC is hex 80</span></span><br />
<div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: x-small;"> send(0x01); // Address of register is hex 1</span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: x-small;"> send(0x00); // Value into register is hex 0</span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: x-small;">endTransmission;</span><br />
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<span style="font-size: x-small;"><span style="font-size: small;"><span style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;">Hex is hexadecimal notation. It is more convenient to write in hex notation rather than binary notation. Most data sheets give you register address value in hex and register value in binary. You can use any notation in your code but you have to indicate which notation.</span></span></span><br />
<br />
<span style="font-size: x-small;"><span style="font-size: small;"><span style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif;">You can convert binary to hex with one of many online tools such as <a href="http://easycalculation.com/hex-converter.php">this</a>. </span></span></span></div><br />
The following code sends one value to 4 registers. This example is typical for setting volume. The same value is assigned to all the internal DACs. Say for example the volume control of the DAC is 1/4 db and you want to set a -10 db volume. The value to use is -40 (you don't have to specify which notation because the default is decimal notation), and assume the registers to control the volume are registers 1 through 4<br />
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<div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: x-small;">beginTransmission(0x80); // Address of DAC is hex 80</span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: x-small;"> send(0x01); // Address of register 1 is hex 1</span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: x-small;"> send(40); // Value into register 40</span><br />
<span style="font-size: x-small;"> </span><span style="font-size: x-small;">send(0x02); // Address of register 2 is hex 2</span> <br />
<div><span style="font-size: x-small;"> send(40); // Value into register 40</span><br />
<span style="font-size: x-small;"> send(0x03); // Address of register 3 is hex 3</span> <br />
<div><span style="font-size: x-small;"> send(40); // Value into register 40</span></div><span style="font-size: x-small;"> send(0x04); // Address of register 4 is hex4</span></div><div><div><span style="font-size: x-small;"> send(40); // Value into register 40</span></div></div><span style="font-size: x-small;"> </span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: x-small;">endTransmission;</span></div><br />
<span style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif; font-size: small;">That's it.</span><br />
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<span style="font-family: "Helvetica Neue",Arial,Helvetica,sans-serif; font-size: small;">Update (October, 12, 2010): I just implemented and tested the basic code to control the Buffalo II DAC's volume. However, I couldn't program multiple registers within a single beginTransmission and endTransmission pair as shown above. I had to program each register with beginTransmission...endTransmission separately. You can see the code <a href="http://hifiduino.wordpress.com/2010/10/12/arduino-for-buffalo-ii/">here</a>. </span><br />
<ul></ul>Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-5963718918139647263.post-62760031699423857892010-02-22T22:18:00.000-08:002010-02-24T09:39:07.372-08:00Audiophile HQCD<div style="font-family: "Trebuchet MS",sans-serif;">Finally got my copy of Bondy Chiu's audiophile recording from Hong Kong. It was sold out over Christmas...</div><div style="font-family: "Trebuchet MS",sans-serif;"><a href="http://www.hqcd.jp/eng.html">HQCD</a> is a higher quality pressing by using lens quality plastic and silver allow first developed for the now dead HD-DVD.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">Bondy Chiu (you can hear her music <a href="http://www.myspace.com/bondychiu">here</a>) is a Hong Kong-based artist that with Ken Poon (his blog is <a href="http://www.designwsound.com/dwsblog/">Design with Sound</a>), a recording engineer and audiophile has created perhaps the first mass-market Audiophile CD.<br />
</div><div style="font-family: "Trebuchet MS",sans-serif;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2LQG0Vso1h2NnOYz3DriDn0fUjbqmK14z4NW6fRhyphenhyphen0YJ5Iyw0AfG9NAiM2Ximc0LdMIMAtBYlUsb9JXyfmuPEByGQN7Cv_1OjyQRSW64axwnBYGK93kJPbDXzw4pG_g2PR97aLUGs4bY/s1600-h/P1020524.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="376" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2LQG0Vso1h2NnOYz3DriDn0fUjbqmK14z4NW6fRhyphenhyphen0YJ5Iyw0AfG9NAiM2Ximc0LdMIMAtBYlUsb9JXyfmuPEByGQN7Cv_1OjyQRSW64axwnBYGK93kJPbDXzw4pG_g2PR97aLUGs4bY/s400/P1020524.JPG" width="400" /></a></div><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">The CD sounds very good, and if you got friends in Hong Kong, can be purchased for around HK$ 160.</div><br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuiCQ5_Rsa0bgko_f4B_03jaBH_Tk5SO6osaYhP-GPbt-lB36eaUfVe0sthx3qZKmAc71d1fZtur1zhyphenhyphenhvnFUr_IQ3swrBCi33gnQmvYgrmkffe2IZM1ibErgqN2BbJnFKho0dfkWzvcU/s1600-h/P1020522.JPG"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuiCQ5_Rsa0bgko_f4B_03jaBH_Tk5SO6osaYhP-GPbt-lB36eaUfVe0sthx3qZKmAc71d1fZtur1zhyphenhyphenhvnFUr_IQ3swrBCi33gnQmvYgrmkffe2IZM1ibErgqN2BbJnFKho0dfkWzvcU/s400/P1020522.JPG" /></a><br />
<div style="clear: both;"></div>Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-5963718918139647263.post-61417851059811568602010-02-17T11:04:00.000-08:002010-02-19T15:59:46.054-08:00Programming Buffalo II DAC: I2C IsolationAs extreme care has been afforded to reduce noise on Buffalo II, perhaps it would be also prudent to implement the I2C isolation solution to prevent any noise sneaking through an external microprocessor such as Arduino on the I2C lines.<br />
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Note: a reader alerted me that the on-board microprocessor goes to sleep after setting up the registers of the DAC. In such case, there should be no additional noise from the on-board microprocessor. However, when the microprocessor is sleeping, only an interrupt can wake it up. If one uses the Arduino as the external microprocessor, some of the code may not be interrupt based, for example polling IR remote signals. So, if the microprocessor is doing more than just setting up the registers at power-on, in general it is not a good idea to put the microprocessor to sleep. Therefore some isolation in the i2c lines would be a welcomed noise avoidance implementation.<br />
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Analog Devices magnetic coupling devices has a solution for this task: <a href="http://www.analog.com/en/interface/digital-isolators/adum1250/products/product.html">The ADum1250</a>. Previous observations <a href="http://hifiduino.blogspot.com/2009/03/opto-isolation-for-i2c.html">here </a>indicate that this is the best solution.<br />
<blockquote><span style="font-size: small;">The ADuM1250/ADuM1251<sup>1</sup> are hot swappable digital isolators with nonlatching, bidirectional communication channels compatible with I<sup>2</sup>C® interfaces. This eliminates the need for splitting I<sup>2</sup>C signals into separate transmit and receive signals for use with standalone optocouplers.</span><br />
<span style="font-size: small;">The ADuM1250 provides two bidirectional channels, supporting a complete isolated I<sup>2</sup>C interface. The ADuM1251 provides one bidirectional channel and one unidirectional channel for those applications where a bidirectional clock is not required.</span><br />
<span style="font-size: x-small;"><span style="font-size: small;">Both the ADuM1250 and ADuM1251 contain hot swap circuitry to prevent glitching data when an unpowered card is inserted onto an active bus</span>. </span></blockquote>The <a href="http://www.analog.com/static/imported-files/application_notes/AN_913.pdf">application note</a> indicates that side 1 (left) should be used for the device (the DAC) and side 2 for the I2C bus (Arduino)<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVIGW8FVaZJyMiH1TDWNhm_4ljKWgHxvR4HkGQTcgljaKOLEKavH2ZqS-5UKXjneFXjNiaHWGRncGHvZNncHQk4sUP-I6N0XypBDQGfYEkHb5ON50MlzrWiuetYxGUd5fSeno8hbwTdEA/s1600-h/adum.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="185" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVIGW8FVaZJyMiH1TDWNhm_4ljKWgHxvR4HkGQTcgljaKOLEKavH2ZqS-5UKXjneFXjNiaHWGRncGHvZNncHQk4sUP-I6N0XypBDQGfYEkHb5ON50MlzrWiuetYxGUd5fSeno8hbwTdEA/s400/adum.jpg" width="365" /></a></div><br />
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The pull up resistors on side 2 (right side) in the diagram are already implemented in Arduino (inside the uP and enabled in software).<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiltdrgjeMaSxowEx_O9YHYchAaRnPlMYwmRy3AzbTCw8Cfv8gNtM8IwyCfMnHm7cdE_i1W0TlrwZ9uacr2ch1DgZCOOkS_ItSBsEi_FCSMJ2XlzQ6DLNW9MHKlJicGvtU5eRdtcUUUaaw/s1600/arduino_diecimila.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="251" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiltdrgjeMaSxowEx_O9YHYchAaRnPlMYwmRy3AzbTCw8Cfv8gNtM8IwyCfMnHm7cdE_i1W0TlrwZ9uacr2ch1DgZCOOkS_ItSBsEi_FCSMJ2XlzQ6DLNW9MHKlJicGvtU5eRdtcUUUaaw/s400/arduino_diecimila.jpg" width="400" /></a></div><br />
The pull-up resistors on side 1 (left side) I believe are already implemented in Buffalo II as R14 and R15? -Need to confirm with the designers.<br />
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<div style="margin-left: 1em; margin-right: 1em;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTfIIuU03RqQjnPSbl1P0pRf4NFgDE3vNNjMXZcCmUSECJB1SVZtfRrnRnAgMjf2j4tStOWT4MVg5eWU-R2sohbLMKVRanImVTtz-wRWSsM9hxKalfcCcprnyiAC94EAHIa4Jbb-zdOi4/s1600-h/buffalo2_whole-2.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTfIIuU03RqQjnPSbl1P0pRf4NFgDE3vNNjMXZcCmUSECJB1SVZtfRrnRnAgMjf2j4tStOWT4MVg5eWU-R2sohbLMKVRanImVTtz-wRWSsM9hxKalfcCcprnyiAC94EAHIa4Jbb-zdOi4/s320/buffalo2_whole-2.jpg" width="219" /></a></div><br />
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<div style="clear: both;"></div>Unknownnoreply@blogger.com6tag:blogger.com,1999:blog-5963718918139647263.post-7646163642166898812010-02-11T23:10:00.000-08:002010-03-04T23:35:50.239-08:00Buffalo II DAC Clock Jitter at 0.1 psec RMS?In the previous post we found that the Crystek oscillator used in the Buffalo II DAC is very good, better than the typical oscillator found in many hi end audio equipment, but obviously not as good as the best money can buy. The phase noise graphs look sort close to each other, but how much different are they?<br />
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Audiophiles are accustomed to hear jitter values in terms of pico-seconds (psec) RMS, and many oscillators are spec'ed at 1 psec jitter. We know that phase noise is another way to measure jitter, and that jitter RMS values represent the area under the curve. One must realize that the graph is in logarithm scale resulting in large differences even though the curves are sort of close to each other.<br />
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Analog Devices has an <a href="http://www.analog.com/static/imported-files/tutorials/MT-008.pdf">excellent tutorial</a> on understanding jitter values <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg843Gz8j6sSdpDiB3u5NgFFlnr1KCFrLB6elOQKxgA-5ImzQZpoXw2yBn6eu85XPCHDqvV-akd0SHvRrm0OpOPvrkwSz42sWeiJTZLBf4JelvnDFtr6MfHFp3stryQoKYiOAa7dF1RaXw/s1600-h/phse+to+jitter.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="310" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg843Gz8j6sSdpDiB3u5NgFFlnr1KCFrLB6elOQKxgA-5ImzQZpoXw2yBn6eu85XPCHDqvV-akd0SHvRrm0OpOPvrkwSz42sWeiJTZLBf4JelvnDFtr6MfHFp3stryQoKYiOAa7dF1RaXw/s400/phse+to+jitter.jpg" width="400" /></a></div><br />
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You can use the formulas to calculate jitter RMS from phase noise data, but there are easy to use on-line tools that calculate jitter RMS from data you find in datasheets. One such tool is the <a href="http://www.jittertime.com/resources/pncalc.shtml">Phase Noise Calculator</a> from www.jittertime.com (a consultancy on the topic of jitter)<br />
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So lets calculate the jitter RMS value for each of the oscillators we compared in the previous post.<br />
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<div style="color: red;">Buffalo II oscillator</div><br />
We find the data points in the graph and enter them in the tool as shown:<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjdlocBmvL2TstheTODddQ9-okHf_f9FtvaMQ4RpY_SBE22qNRyvXsMGkG68-IPtXmZLRmZYQhrHesHOHDXlYUwTEeJlqKS9J6v6JXhMRquFJhOXt3WPml9l9xzbSO-jfRjsBR7WB3p58/s1600-h/Picasa+3+2112010+103310+PM.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjdlocBmvL2TstheTODddQ9-okHf_f9FtvaMQ4RpY_SBE22qNRyvXsMGkG68-IPtXmZLRmZYQhrHesHOHDXlYUwTEeJlqKS9J6v6JXhMRquFJhOXt3WPml9l9xzbSO-jfRjsBR7WB3p58/s400/Picasa+3+2112010+103310+PM.jpg" /></a>The result is 0.446 psec. (if you are wondering why the result is less than the sum of the jitter in each segment, is because they <span class="classnotnav">add as Root Sum-of-Squares)</span><br />
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This value agrees with the value is the specification ( typically 0.5 psec). We do the same for the other curves and we find the following:<br />
<ul><li>Crystek 950 (Buffalo II): 0.446 psec</li>
<li>Wenzel oscillator: 0.075 psec</li>
<li>Typical Oscillator (Buffalo I): 29.9 psec</li>
</ul><br />
Those are BIG differences when we convert to jitter RMS values. the Wenzel measures 75 femto seconds!. The Crystek 950 measures the expected half a psec; but the typical oscillator measure 30 psec?. But wait a minute, aren't those oscillators spec'ed at 1 psec?.<br />
<br />
Lets looks at the specification of the oscillator found in Buffalo I: Crystek c33xx. The <a href="http://www.crystekcrystals.com/crystal/spec-sheets/clock/C33xx.pdf">spec</a> says: Jitter RMS: 12KHz-80MHz: 0.5 psec. Notice that the jitter is measured after 12 KHz whereas the phase noise plots we see for the better parts starts at 10 Hz. If we instead measure the Jitter RMS for the Crystek 950 shown in the graph with the same scale, of 12 KHz to 80 MHz, we get the value of 0.13 psec.<br />
<br />
I used the numbers found in the <a href="http://www.crystekcrystals.com/crystal/spec-sheets/clock/CCHD-950.pdf">spec</a> for an 80MHz oscillator and got 0.115 psec for 12KHz to 80MHz. The best spec in the datasheet is for the 100MHz clock with a jitter value of 0.094 psec RMS (12KHz-80MHz). Maybe the custom clock Crystek is making for TPA has better phase noise values than what is stated in the specifications. (Update: according to Brian of TPA, the phase noise specification for their parts is the same as the standard parts)<br />
<br />
Thus:<br />
<ul><li>Clock for Buffalo I: 0.5 psec RMS (12KHz-80MHz)</li>
<li>Clock for Buffalo II: 0.115 psec RMS (12KHz-80MHz)</li>
</ul><br />
What offset frequency interval is used for audio to calculate jitter? I don't think there are standards in audio, but for other applications there are standards. <a href="http://www.audiodesignline.com/222700730;jsessionid=ZYFULY5FAS0CDQE1GHPCKH4ATMY32JVN?printableArticle=true">This article</a> cites two standards:<br />
<blockquote>As an example, SONET uses a frequency offset of <span style="color: red;">12kHz to 20MHz</span> from the carrier signal to integrate the area under the phase noise plot to measure phase jitter. Fiber Channel uses a frequency offset of <span style="color: red;">637kHz to 10MHz</span> from the carrier signal to integrate the area under the phase noise plot to measure phase jitter.</blockquote>According to<a href="http://www.analog.com/en/rfif-components/rfif-transceivers/adf4360-9/products/FAQ_How_do_you_determine_the_bandwidth_over_which/resources/faq.html"> Analog Devices</a>,<br />
<blockquote>It is a little tricky to specify the bandwidth over which phase noise should be integrated in order to calculate the jitter which will actually be observed when that clock signal is used to clock a converter. There are many variables which are seldom known with accuracy – such as the inherent bandwidth of the sample clock circuit on the converter. Also, it is very difficult to actually measure the broadband phase noise of a clock signal beyond an offset of a few MHz. ... For a true "broadband" jitter calculation some assumptions and simplifications must be made. One assumption made by ADIsimCLK, for example, is that the upper offset integration limit is one-half the clock frequency. The lower offset integration limit is assumed to be between 100 Hz and 1 kHz. </blockquote>What frequency interval matters then?<br />
<br />
If we take a previous datasheet of the Crystek 950 clock and compare it with the current datasheet, we see that the "close-in" phase noise (closer to the crystal frequency) has increased and that "broad band" phase noise (away from the crystal frequency).<br />
<br />
It seems that the engineers at Crystek focused on improving the broadband phase noise values and were willing to tradeoff the close-in phase noise. This implies that broadband phase numbers (or the "noise floor" of the oscillator) is a more important value than close-in noise (at least for the market that this crystal is intended to be used, -which I am sure it is NOT DIY DAC boards :-))<br />
<br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyfn-B2A3xif4SsMKBIoUVuNaBcqqM-3dFK515XbzGrMPeGS3852Trt_Ksg2lVbUVI8eZ4kLRAYEJT81-G3VlFkDUx86hzG0buNE2PD5FFKlf2pOwfU_4hDBZlKy2PjCOkxCyjw6k4iWw/s1600-h/950.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="355" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyfn-B2A3xif4SsMKBIoUVuNaBcqqM-3dFK515XbzGrMPeGS3852Trt_Ksg2lVbUVI8eZ4kLRAYEJT81-G3VlFkDUx86hzG0buNE2PD5FFKlf2pOwfU_4hDBZlKy2PjCOkxCyjw6k4iWw/s400/950.jpg" width="400" /></a></div><br />
<br />
Perhaps it depends on the application<br />
<br />
According to <a href="http://www.analog.com/static/imported-files/tutorials/MT-008.pdf">tutorial</a> from Analog Devices,<br />
<ul><li>Close-in phase noise limits the frequency resolution </li>
<li>Broadband phase noise reduces SNR</li>
</ul>According to the discussion on <a href="http://www.diyaudio.com/forums/digital-line-level/117238-ess-sabre-reference-dac-8-channel-30.html#post1447292">DIYAUDIO</a> (thanks rossl for pointing this out in the comments) close-in phase noise is what is important for high-end DAC applications.<br />
<br />
YET another data point for frequency interval<br />
<br />
A reader alerted me to an excellent AES paper on jitter for audio components, <a href="http://www.wolfsonmicro.com/uploads/documents/en/Specifying%20Jitter%20Performance.pdf">available for free</a> from Wolfson Micro. There, the authors propose a "baseband" value of 100Hz to 40K Hz<br />
<br />
If we use these frequency values we obtain (via the handy <a href="http://www.jittertime.com/resources/pncalc.shtml">online jitter calculation tool</a>) the following jitter values:<br />
<ul><li>1.6 psec or 1600 fsec for a c33xx class clock (100Hz-40KHz)</li>
<li>0.046 psec or 46 fsec for a 950 class clock (100Hz-40KHz)</li>
</ul><br />
Unfortunately most of the research on the effect of phase noise revolve around digital telecommunication, where the frequency is in the 100s of MHz. There clock jitter determines the SNR and effectively the bandwidth of the devices, and the phase noise value that is important is the broadband phase noise.<br />
<br />
So what is the effect of phase noise in audio?<br />
<br />
According to this <a href="http://www.grimmaudio.com/whitepapers/clock%20jitter%20spec.pdf">AES paper</a> by Bruno Putzeys (Hypex, Grimm Audio) it is just noise.<br />
<br />
I also took a look at other implementations of the ESS DAC and what kind of clock they use. It seems that only DIY versions can "afford" the high-end clock... Also note that the ESS evaluation board uses a "standard" crystal, rather than a clock (or so it looks like)<br />
<br />
<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8SZMBzoy7z5QdpowVSx5yWjn7s5tWjjMaVhXWEt3J5w7GoS5n5WtTytOj_qcsqTOxq2JnfEPqwdrWbp4E4lBQ8-4AB2dU6pw20myOLJQrNvZm5JaZkepRdFXOrcQEC1JKwbWT8Tu_X7M/s1600-h/crystek+in+ess.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="272" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8SZMBzoy7z5QdpowVSx5yWjn7s5tWjjMaVhXWEt3J5w7GoS5n5WtTytOj_qcsqTOxq2JnfEPqwdrWbp4E4lBQ8-4AB2dU6pw20myOLJQrNvZm5JaZkepRdFXOrcQEC1JKwbWT8Tu_X7M/s400/crystek+in+ess.jpg" width="400" /></a></div><br />
Eastern Electric DAC<br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxC6gKudcH1fUh02je8LAqCrSEXXFcbpr3A2SzsVtkJ09u2lAk0n4HaeTKW-09xmwjheVFrEIMUoUSz5zKSIShXzRqzU_DFOvm_veP9RS2LBfulToDFR28Hc6zYfBcL7vhY4dsuEY3VOI/s1600-h/IMG_8578.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="167" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxC6gKudcH1fUh02je8LAqCrSEXXFcbpr3A2SzsVtkJ09u2lAk0n4HaeTKW-09xmwjheVFrEIMUoUSz5zKSIShXzRqzU_DFOvm_veP9RS2LBfulToDFR28Hc6zYfBcL7vhY4dsuEY3VOI/s400/IMG_8578.jpg" width="400" /></a></div><br />
<div style="clear: both;"></div>Unknownnoreply@blogger.com5tag:blogger.com,1999:blog-5963718918139647263.post-43690381873688384572010-02-11T20:19:00.000-08:002011-07-28T09:38:16.316-07:00Clock in Buffalo II DAC<div style="font-family: "Trebuchet MS",sans-serif;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTCL9G_kYAGIkutbxe4k39V4-at_gDho8X8gPeZImXFGHvrSgLLsSTQUAiY2A9QARtVWGexhxha_IXE0gYTayrp_hwcvZOxHSTcfRMiuuuYhePqcQb9tz9C6M1c6UVDOYKPJAdxYPhy-o/s1600-h/crystek.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="238" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTCL9G_kYAGIkutbxe4k39V4-at_gDho8X8gPeZImXFGHvrSgLLsSTQUAiY2A9QARtVWGexhxha_IXE0gYTayrp_hwcvZOxHSTcfRMiuuuYhePqcQb9tz9C6M1c6UVDOYKPJAdxYPhy-o/s320/crystek.jpg" width="320" /></a></div><br />
According the Brian in this <a href="http://www.diyaudio.com/forums/twisted-pear/160782-buffalo-ii-4.html#post2080706">post</a>, the clock in Buffalo II is not only the top-of-the line product from Crystek, but a custom made model with even better specifications.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">For those with sharp eyes, the photo of the Buffalo II prototype has a 50 ppm (temperature stability) clock, but the production models will have a 20 ppm part.Temperature stability is related to the quality of the quartz crystal used in the clock. It is therefore safe to assume that this will also improve the jitter figures.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">But how good is Crystek's best oscillator?</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">There is a <a href="http://www.crystekcrystals.com/crystal/appnotes/ImpactUltralow.pdf">white paper</a> by Crystek showing "phase noise" curves for the 950 oscillator and compared to a typical oscillator. I copied the charts and overlaid them together. In addition I took a look at the specifications of a ultra low phase noise <a href="http://www.wenzel.com/pdffiles1/Oscillators/ULN_30_to_130.pdf">Wenzel oscillator</a> and a <a href="http://www.spectratime.com/product_downloads/lcr_spec.pdf">Rubidium oscillator</a> and plotted the data on the same chart. The Rubidium is a "$900 low cost" version. Perhaps they are best at frequency stability over a long period of time and therefor they cost so much. The Wenzel oscillators are the lowest phase noise you can find and are used in High Energy Physics and Radio Astronomy applications. If you work for NASA or CERN, maybe you can borrow one of these clocks and hook it up to your DAC :-).</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><span style="font-family: "Trebuchet MS",sans-serif;">BTW, "phase noise" is just another way to measure jitter. Jitter, typically measured in psec is the area under the phase noise curve. Thus jitter gives you the total deviation from ideal and phase noise gives you the spectrum of that deviation. However, comparing jitter figures is not easy because manufacturers select different frequency range (say 100Hz to 100KHz or 10Hz to 1MHz) and each gives different numbers. Best to compare phase noise numbers. The graph below shows the phase noise curves. One can see that in order to improve on the clock selected for the Buffalo II DAC, one would have to get a Lab grade oscillator</span><br />
<br />
<span style="font-family: "Trebuchet MS",sans-serif;">Update: NEL AE-X3A3 oscillators have better specifications than Crystek 950. The NEL Oven controlled oscillator is even lower noise (not sure how much they cost)</span><br />
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<span style="font-family: "Trebuchet MS",sans-serif;">(Clik for larger image) </span><br />
<span style="font-family: "Trebuchet MS",sans-serif;"> </span><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB_3ILHk0kn8bDhVvsvw5gee8bnMCk7GGh_Xq2r9Ek33WUGHN-ghOpn3lixUGpi20oYVlyMN14hs7Opoj4RfCTPmUM7P0eGClSQK38dI0ci6Qbp4sFaG2NA0mx0Hhyphenhyphenv_bFcisRXYh_7O8/s1600-h/clockPlots.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="377" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB_3ILHk0kn8bDhVvsvw5gee8bnMCk7GGh_Xq2r9Ek33WUGHN-ghOpn3lixUGpi20oYVlyMN14hs7Opoj4RfCTPmUM7P0eGClSQK38dI0ci6Qbp4sFaG2NA0mx0Hhyphenhyphenv_bFcisRXYh_7O8/s400/clockPlots.jpg" width="400" /></a></div><br />
<div class="separator" style="clear: both; text-align: center;"></div>How is Ultralow Phase Noise Achieved?<br />
<br />
According to the author in the Crystek white paper,<br />
<blockquote>"A commodity oscillator is nothing more than an ASIC and a quartz crystal blank. In most cases, it does not even have an internal bypass capacitor. The crystal blank is an AT-cut strip with Q of about 25 K to 45 K. This low Q limits the close-in phase noise. The ASIC with all its transistors limits the floor noise to about -150 dBc/Hz. On the other hand, the true ultralow phase noise oscillator uses a discrete high-performance oscillator topology with a packaged crystal with a Q greater than 70 K for excellent close-in phase noise. The discrete oscillator topology establishes the SNR, and hence the floor is lower than -160 dBc/Hz. Therefore, superior performance is obtained with very high Q crystals and a good discrete topology."</blockquote>How is the Phase-Noise graph obtained? The chart is one half of the power-frequency distribution of the variation from ideal. Instruments are available to generate such charts.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhuiddQsr2_C71W87HA4L-upUN_QIKhqbEf3lxeWHUocBbSxFebsEGFCfVW8sG72J_z55Mj_oGLiJIRvmVwlp-QEkSM3jVDCVb6zyflM0WgUdcOy6tgAj6o4ecmRrZRVwwt04zYO9iFfGE/s1600-h/PhaseNoise.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="305" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhuiddQsr2_C71W87HA4L-upUN_QIKhqbEf3lxeWHUocBbSxFebsEGFCfVW8sG72J_z55Mj_oGLiJIRvmVwlp-QEkSM3jVDCVb6zyflM0WgUdcOy6tgAj6o4ecmRrZRVwwt04zYO9iFfGE/s400/PhaseNoise.jpg" width="400" /></a></div>This <a href="http://cp.literature.agilent.com/litweb/pdf/N9068-90011.pdf">manual</a> has a good tutorial on phase noise<br />
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Quarts oscillators is an "old" technology. "<a href="http://cp.literature.agilent.com/litweb/pdf/5965-7662E.pdf">Fundamentals of Quartz Oscillators</a>", an application note from HP from the late '70s is a good read.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2JEAHIxiXvEGiCDhyK2-gOZfxdzJnozJ_iDKUiEp9j8MXlwzZG10jhDhYG1Fvor2J_wGX-OQWAbQSBCkQiKG5XzrNa2ygHwKy6ARLaSYV9s-SYm0cU6Hs0pRUhtevhuplu-bibDaWI5M/s1600-h/FireShot+Pro+capture+%23182+-+%275965-7662E_pdf+%28application_pdf+Object%29%27+-+cp_literature_agilent_com_litweb_pdf_5965-7662E_pdf.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2JEAHIxiXvEGiCDhyK2-gOZfxdzJnozJ_iDKUiEp9j8MXlwzZG10jhDhYG1Fvor2J_wGX-OQWAbQSBCkQiKG5XzrNa2ygHwKy6ARLaSYV9s-SYm0cU6Hs0pRUhtevhuplu-bibDaWI5M/s320/FireShot+Pro+capture+%23182+-+%275965-7662E_pdf+%28application_pdf+Object%29%27+-+cp_literature_agilent_com_litweb_pdf_5965-7662E_pdf.jpg" /></a></div><br />
<div style="clear: both;"></div>Unknownnoreply@blogger.com2tag:blogger.com,1999:blog-5963718918139647263.post-53590808778333150752010-02-11T00:05:00.000-08:002010-11-05T17:37:21.488-07:00The Buffalo II DAC: Best Bang-for-Buck<div style="font-family: "Trebuchet MS",sans-serif;">(Update, Nov. 2010: I've developed Arduino code to control the Buffalo DAC. Check my other blog: www.hifiduino.wordpress.com) <br />
<br />
<a href="http://www.twistedpearaudio.com/digital/buffalo.aspx">TwistedPearAudio</a> Released the Buffalo II DAC</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">This is the 3rd TPA iteration for the top of the line ESS DAC. The first iteration was for the ESS 9008 (24bit) DAC and the second and third are for the ESS 9018 (32bit).</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">Although it is priced at $249, the ESS DAC includes a spdif receiver, a high speed ASRC and a 32-bit DAC. In Addition, the Buffalo II includes a top-of-the line, ultra low jitter clock from Crystek and a ultra-low noise shunt regulator for the analog section of the DAC.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">I think Buffalo II is the new bang-for-buck leader. If we compare a comparable OPUS DAC offering we have the following:</div><ol style="font-family: "Trebuchet MS",sans-serif;"><li>Opus DAC (WM8741): $75</li>
<li>Opus Spdif Receiver (WM8804): $75</li>
<li>Metronome (ASRC): $75</li>
<li>Upgrade Clock (you must mod yourself): $30</li>
<li>Upgrade analog regulation (e.g. Placid, and mod yourself): $40</li>
</ol><div style="font-family: "Trebuchet MS",sans-serif;">Total: $295</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">To be fair, the OPUS does not require an output stage and associated power supply, and the Buffalo II requires an output stage.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">In-depth comparison between Buffalo I DAC (ESS 9008) and Buffalo II DAC (ESS 9018) also shows that the new DAC is a better deal than the old DAC <span style="font-size: xx-small;"><span style="font-family: "Courier New",Courier,monospace;">(Buffalo I photo scraped from "buyer of board #93 without permission)</span></span></div><div class="separator" style="clear: both; text-align: center;"></div><div style="text-align: center;">BUFFALO I DIGITAL TO ANALOG CONVERTER</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6uFuguEspBi1w3WrlU5XX98Lar2bLbx58TvaHOV2pEjjWbUQ59IvqVaKYF_i3H0-OtBB9xToBxvFIM2HqUYdQvrImQtMCYQpmr26-nuVnzOCMSM8sRa5ChjUsOx8MYeHPohzokj9JbGs/s1600-h/005.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="233" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6uFuguEspBi1w3WrlU5XX98Lar2bLbx58TvaHOV2pEjjWbUQ59IvqVaKYF_i3H0-OtBB9xToBxvFIM2HqUYdQvrImQtMCYQpmr26-nuVnzOCMSM8sRa5ChjUsOx8MYeHPohzokj9JbGs/s400/005.jpg" width="400" /></a></div><div style="text-align: center;">BUFFALO II DIGITAL TO ANALOG CONVERTER</div><br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEge8T6aP6kvL-Y0ibRcS4CFPQep2GJ4tC7MR2OU3n2DpAln4ezPWaDfoEUr_qD2A_1Az-OyqTOV-sdS_N1w7tHJO6hw6SGWvt4g1UKQKZXGMTZD_0USYyiKE_calmjJRqHkL7JbJ1CcSis/s1600-h/bufII.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEge8T6aP6kvL-Y0ibRcS4CFPQep2GJ4tC7MR2OU3n2DpAln4ezPWaDfoEUr_qD2A_1Az-OyqTOV-sdS_N1w7tHJO6hw6SGWvt4g1UKQKZXGMTZD_0USYyiKE_calmjJRqHkL7JbJ1CcSis/s400/bufII.jpg" width="386" /></a><br />
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<div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: small;">Buffalo I ---------------Buffalo II</span></div><div style="font-family: "Courier New",Courier,monospace;"><br />
</div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: small;">Panasonic caps: <a href="http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PCE4546CT-ND">$0.51</a> ---Oscon caps: <a href="http://www.mouser.com/ProductDetail/Vishay-OS-CON/94SA107X0020FBP/?qs=sGAEpiMZZMtm5nWh%2fhvnH6cYt9dOwxwfWzMV47FUM%252b0%3d">$3.14</a></span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: small;"><a href="http://www.mouser.com/ProductDetail/Vishay-OS-CON/94SA107X0020FBP/?qs=sGAEpiMZZMtm5nWh%2fhvnH6cYt9dOwxwfWzMV47FUM%252b0%3d"></a></span> </div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: small;">Crystek 33xx: <a href="http://www.mouser.com/ProductDetail/Crystek-Crystals/C3391-24576/?qs=sGAEpiMZZMsBj6bBr9Q9aQYNpWdONf7RoDFjt0g1tGU%3d">$2.31</a> -----Crystek 950: <a href="http://www.mouser.com/ProductDetail/Crystek-Crystals/CVHD-950-80000/?qs=sGAEpiMZZMukHu%252bjC5l7YXO8aveU7WeumN5FYmvg7Wk%3d">$27.70</a></span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: small;"><a href="http://www.mouser.com/ProductDetail/Crystek-Crystals/CVHD-950-80000/?qs=sGAEpiMZZMukHu%252bjC5l7YXO8aveU7WeumN5FYmvg7Wk%3d"></a></span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: small;">ESS 9008: <a href="http://ecommerce.ismosys.com/ordering/product_info.php?manufacturers_id=34&products_id=387">$47.90</a> --------ESS 9018: <a href="http://ecommerce.ismosys.com/ordering/product_info.php?manufacturers_id=34&products_id=479">$65.60</a></span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: small;"><a href="http://ecommerce.ismosys.com/ordering/product_info.php?manufacturers_id=34&products_id=479"></a></span></div><div style="font-family: "Courier New",Courier,monospace;"><span style="font-size: small;">Regulator: <a href="http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=497-4240-1-ND">$.75</a> ---------LT 1763 Regulator: <a href="http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=LT1763CS8-3.3%23PBF-ND">$4.13</a></span></div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">Total: 53.75 ---------------------------Total: 115.11</div><span style="font-family: "Trebuchet MS",sans-serif;">Difference: $61.36</span><br />
<br />
<span style="font-family: "Trebuchet MS",sans-serif;">I believe the Buffalo I sold for $169. If we add the price differential for the 4-layer board, and the time spent designing and prototyping and testing the new board, we can easily reach the $80 price difference between the old Buffalo and Buffalo II.</span><br />
<br />
<span style="font-family: "Trebuchet MS",sans-serif;">Ah! I forgot the ultra-low noise dual analog regulator, you get that for FREE! (Expect to pay $60 to $120 for two shunt low noise regulators from 3rd parties)</span><br />
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<span style="font-family: "Trebuchet MS",sans-serif;">Update:</span><br />
<ul><li><span style="font-family: "Trebuchet MS",sans-serif;">There are a couple of dozen additional components in the back side of the PCB</span></li>
<li><span style="font-family: "Trebuchet MS",sans-serif;">The clock is a custom made 20 ppm (standard is 25-50 ppm) model for TPA</span></li>
</ul><br />
<b><span style="font-family: "Trebuchet MS",sans-serif;">COMPARISON WITH BUFFALO 32S</span></b><br />
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<span style="font-family: "Trebuchet MS",sans-serif;">I believe the main difference between Buffalo II and Buffalo 32s (aside from having the I/V stage in a separate board) is the analog supply. It appears (from pictures, I don't have the boards and there are no schematics for Buffalo 32s) the analog supply of Buffalo 32s is similar to the one found in Buffalo I.</span><span style="font-family: "Trebuchet MS",sans-serif;"> </span><br />
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<span style="font-family: "Trebuchet MS",sans-serif;">Buffalo 32s analog supply: based on two LM4971 single opamps</span><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6AXp3OOKm4_TTqcdOLGLjZ_p1IFUmoX0BA-o8wz8z2c39PACgmCw1gRwTriMytfaDaJw7700XWhMYY6V2LCdrgn9d71-VBhIP6G6tC0NaPGWkB1NeoXv545as1-WVyLQPFm2f3tGbCRc/s1600-h/sabre-1.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="176" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6AXp3OOKm4_TTqcdOLGLjZ_p1IFUmoX0BA-o8wz8z2c39PACgmCw1gRwTriMytfaDaJw7700XWhMYY6V2LCdrgn9d71-VBhIP6G6tC0NaPGWkB1NeoXv545as1-WVyLQPFm2f3tGbCRc/s400/sabre-1.jpg" width="400" /></a></div><span style="font-family: "Trebuchet MS",sans-serif;">Buffalo I analog supply: based on a single LM4972 dual opamp</span><br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjheduBLOsCkp9cf7u8AtEXsthJeYbCl7mhsiW5hdr8YgXz2VXdy2hZPbbTmiWMBlEmvNaxp1nXZDigRgvismzepC3QOtz0J42OsjXWXhpN6IB5RNKWMzndSdAJQCGaa_Efd88T5r-plBA/s1600-h/IMG_6183+%282%29.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjheduBLOsCkp9cf7u8AtEXsthJeYbCl7mhsiW5hdr8YgXz2VXdy2hZPbbTmiWMBlEmvNaxp1nXZDigRgvismzepC3QOtz0J42OsjXWXhpN6IB5RNKWMzndSdAJQCGaa_Efd88T5r-plBA/s400/IMG_6183+%282%29.jpg" width="400" /></a><span style="font-size: small;"><b><span style="font-family: "Trebuchet MS",sans-serif;"></span></b></span><br />
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<div class="separator" style="clear: both; text-align: center;"></div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-5963718918139647263.post-64408790414221357392010-02-10T12:03:00.000-08:002010-04-22T17:10:26.351-07:00Buffalo II Specification and FAQ<div class="separator" style="clear: both; text-align: center;"></div>This post is to summarize information I find elsewhere<br />
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EXTERNAL POWER SUPPLY REQUIREMENTS<br />
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POWER SUPPLY CURRENT [<a href="http://www.diyaudio.com/forums/twisted-pear/160782-buffalo-ii-8.html#post2095384">link</a>]<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbSAscU5lwgIE43EOjPHW89GNn3ydxoWep3C0HBWYlW_ZrTJN02RHdWddofXNfOLrsU5GZ-X4kJP45tRMpCofGlRDSyl_ECEGoJ9-pnuMRec6Bfqq2ZaYfyyQwPA2uLOm2ZOyGdnsjwQc/s1600-h/buffCurrent-1.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbSAscU5lwgIE43EOjPHW89GNn3ydxoWep3C0HBWYlW_ZrTJN02RHdWddofXNfOLrsU5GZ-X4kJP45tRMpCofGlRDSyl_ECEGoJ9-pnuMRec6Bfqq2ZaYfyyQwPA2uLOm2ZOyGdnsjwQc/s320/buffCurrent-1.jpg" /></a></div><br />
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POWER SUPPLY VOLTAGE [<a href="http://www.diyaudio.com/forums/twisted-pear/143315-twisted-pear-audio-buffalo32s-es9018-dac-81.html#post2075797">link</a>]<br />
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The Buff II board has a single PS connection. Because it feeds both the on board LT1763 regulators and the AVCC dual shunt regulator, it must comply to the design of the AVCC dual shunt:<br />
<ul><li>Vmin=5V</li>
<li>Vmax=5.5V (The AVCC shunt regulator is optimized to this voltage)</li>
</ul>AVCC<br />
<br />
According the the <a href="http://www.esstech.com/PDF/sabrewp.pdf">ESS Sabre DAC white paper</a>, AVCC is specified as follows:<br />
<ul><li>Minimum: 1.8V </li>
<li>Nominal: 3.3V (DNR= -132db)</li>
<li>Maximum: 4.0V (DNR> -133db) - see footnote 17 of paper</li>
</ul>INSTALLATION OF AVCC DUAL SHUNT REGULATOR [<a href="http://www.diyaudio.com/forums/twisted-pear/143315-twisted-pear-audio-buffalo32s-es9018-dac-81.html#post2075804">link</a>] [<a href="http://www.diyaudio.com/forums/twisted-pear/160782-buffalo-ii-20.html#post2126572">link</a>]<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqJRhszA0fV6S22YPZOrI7_7FV6QHKo86ltxETWsTE_-CfB-yqtPjSt7JalnM1zDV6_f28zPS0SI_opIimFUvdczXT9h9PFcHcBczfnToK0jdHhB5EfSZj_NJWi2mB2FMBm-8idMYheoc/s1600-h/buffdimansion2.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="328" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqJRhszA0fV6S22YPZOrI7_7FV6QHKo86ltxETWsTE_-CfB-yqtPjSt7JalnM1zDV6_f28zPS0SI_opIimFUvdczXT9h9PFcHcBczfnToK0jdHhB5EfSZj_NJWi2mB2FMBm-8idMYheoc/s400/buffdimansion2.jpg" width="400" /></a></div><br />
<br />
"Also of note, although the AVCC header has four pins, only three are used by our AVCC module. <br />
The AVCC module does not use the DVCC pin. It is there as a convenience to any who might want to use an ESS demo board style AVCC supply (where DVCC is a VREF). Our AVCC module uses its own low noise VREF, not DVCC." <br />
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Note: Buffalo I also derived the AVCC from the DVCC. In the case you wish to replicate such AVCC implementation, you can tap into DVCC as reference and VD will be powering the buffer opamp:<br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWzE3rxNgnA2YYOUYL63qH8BkDdRGCXkv6VkJr_rWRRiH17zdziqlnXtaF6VGqlzz9YgZK8isfpwG6bV0-AnT_nNkzvpNgHczq6_jMo_tEdZ_lae2bpC_QS1phd6kAYOFRpGwtv7ot5xQ/s1600-h/SabreBoardAVCC.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="188" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWzE3rxNgnA2YYOUYL63qH8BkDdRGCXkv6VkJr_rWRRiH17zdziqlnXtaF6VGqlzz9YgZK8isfpwG6bV0-AnT_nNkzvpNgHczq6_jMo_tEdZ_lae2bpC_QS1phd6kAYOFRpGwtv7ot5xQ/s400/SabreBoardAVCC.jpg" width="400" /></a></div><br />
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Normal Operating Conditions [<a href="http://twistedpearaudio.com/forum/default.aspx?g=posts&m=5235#5235">link</a>] <br />
(This is one board, there is slight variations between boards)<br />
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VD=5V. Notice that one LED is brighter than the other. According to TPA this is perfectly normal.<br />
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AVCC1=3.523V, VCC2=3.5626V <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI4VR641RdFlmjSLUCB0Oo4XXL7X9oiFcKm1DuxsIeJ9mt-lhdOXf4pH0gaBMmRZ2bUgjwjMemnUKxB_IUi2WQ0BNFJDv0_evGJO3RHnxn6bkFfvXvhOzYt0TrxPUKnEjIdV0tAMVpFp4/s1600-h/P1020567-1.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="177" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI4VR641RdFlmjSLUCB0Oo4XXL7X9oiFcKm1DuxsIeJ9mt-lhdOXf4pH0gaBMmRZ2bUgjwjMemnUKxB_IUi2WQ0BNFJDv0_evGJO3RHnxn6bkFfvXvhOzYt0TrxPUKnEjIdV0tAMVpFp4/s400/P1020567-1.JPG" width="400" /></a></div><br />
VD=5.5V. Notice that the LEDs' brightness is more uniform.<br />
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AVCC1=3.556V, AVCC2=3.554V<br />
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<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgahYFse99PlaDzHfbGbGRh8ZPQEsboUNoJ0yZkPvHwu8gzefb4Y3peBvwyRe7fIsHq6tiPfMibHwDCy1xaKJUQH7kOHUM9quXHMUdd08gkel8D6Yr5sJ2m0fRLP1CNWku522mPokwS99c/s1600-h/DSC_0436-1.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="170" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgahYFse99PlaDzHfbGbGRh8ZPQEsboUNoJ0yZkPvHwu8gzefb4Y3peBvwyRe7fIsHq6tiPfMibHwDCy1xaKJUQH7kOHUM9quXHMUdd08gkel8D6Yr5sJ2m0fRLP1CNWku522mPokwS99c/s400/DSC_0436-1.JPG" width="400" /></a></div><br />
The shut regulator board can also be installed on the back side of the Buffalo II board (It will get on the way if you are stacking above IVY III)<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZtK9CV4O_BbYXk8FtRpI2rsTNz_Bx_7Bu5QoL8JdjzUCK8hUGLOhOS4FE7mpANcPG1Oq-g72q0tDDIZeccWq06qT1jUVnBd_jVKSPTE7RT720aOHBSLyOc8lNFzigerRqVNjhYO0borc/s1600-h/DSC_0440.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="198" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZtK9CV4O_BbYXk8FtRpI2rsTNz_Bx_7Bu5QoL8JdjzUCK8hUGLOhOS4FE7mpANcPG1Oq-g72q0tDDIZeccWq06qT1jUVnBd_jVKSPTE7RT720aOHBSLyOc8lNFzigerRqVNjhYO0borc/s400/DSC_0440.JPG" width="400" /></a></div><br />
ON BOARD LINEAR REGULATORS<br />
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<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg41SzVOB0mJGRP1WizyBp42y3ikwLXjzBE7sKQL7JstIqPo1cMia-WJygu8DbC5sGAIQCC2cvbOx7NAl6gO4j98Nvs8dJd363SfbyVNAFbu33z3PeKUSwgk8jFp6l7qDFpBjyyeAHLpw/s1600-h/DSC_0370.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="348" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg41SzVOB0mJGRP1WizyBp42y3ikwLXjzBE7sKQL7JstIqPo1cMia-WJygu8DbC5sGAIQCC2cvbOx7NAl6gO4j98Nvs8dJd363SfbyVNAFbu33z3PeKUSwgk8jFp6l7qDFpBjyyeAHLpw/s400/DSC_0370.JPG" width="400" /></a></div><br />
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<ul><li>There are 3 linear regulators <a href="http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1010,C1778,C1764,P1778,D3903">LT 1763</a>. Two are 3.3 V and one is variable set to 1.2V</li>
<li>Noise level: 20uVrms 10Hz to 100KHz (meaning you can't do better than this even if you feed it a cleaner supply). For more information on regulator noise see this <a href="http://hifiduino.blogspot.com/2010/03/comparing-noise-figures-in-linear.html">post</a>.</li>
<li>Regulator Vin max=20V (5.5V max is specified because the same input traces feed the the shunt AVCC regulator which is designed for 5.5V max)</li>
<li><a href="http://hifiduino.blogspot.com/2010/03/comparing-noise-figures-in-linear.html">Comments by Russ</a> on the use of LT1763 as regulator for the Crystek clock: "The reason the LT1763 is a good fit for the clock we use is because that clock in essence has a form of local regulation and decoupling internally."</li>
</ul><ul></ul>OUTPUT IMPEDANCE BUFFALO I, II (from <a href="http://www.diyaudio.com/forums/twisted-pear/160782-buffalo-ii-12.html#post2111740">diyaudio</a>)<br />
<ul><li>195 ohm each output</li>
</ul>According to the <a href="http://www.esstech.com/PDF/sabrewp.pdf">ESS Sabre DAC whitepaper</a> page 4, each of the 8 DACs can be modeled as a voltage source having an output impedance of approx 800 ohm. Since in stereo configuration 4 such dacs are wired in parallel, the effective output impedance is thus 800/4 ~ 200 ohm.<br />
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DUAL MONO INSTALLATION<br />
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Latest <a href="http://www.diyaudio.com/forums/twisted-pear/160782-buffalo-ii-50.html#post2163072">diagram</a> posted at diyaudio<br />
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DIMENSIONS<br />
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<ul><li>Buffalo II board: <a href="http://www.twistedpearaudio.com/forum/default.aspx?g=posts&t=968">2" x 3.3"</a>. This is the same size as the other modules such as OPUS, COD, Buffalo I, etc.</li>
<li>IVY III: From the <a href="http://www.twistedpearaudio.com/images/linestages/ivy3/ivy_3_layout_whole.jpg">layout</a> it appears it is a double size board: 4" x 3.3" </li>
<li>Supplied Standoffs: .5" base standoffs. Inter-board standoffs (not included with the Buffalo II board are .625")</li>
</ul><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigrfv_jmO7LCOKcpVum_JhI4UbXcRdLlfJp_gEitNpKJLyGJf9ySHHxoocuL7mTLMtOpIynl1JNiLynx4JJgh92kkaWYTSiYMk_7c1TKbBk9jOaBTCCkI7ECpldq7hTrInf360u9cqwEY/s1600-h/cs8416mux.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigrfv_jmO7LCOKcpVum_JhI4UbXcRdLlfJp_gEitNpKJLyGJf9ySHHxoocuL7mTLMtOpIynl1JNiLynx4JJgh92kkaWYTSiYMk_7c1TKbBk9jOaBTCCkI7ECpldq7hTrInf360u9cqwEY/s320/cs8416mux.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_fN4xf_LZaRFDQGQHgjwj1W7wDC2odnlqDm796KhusKU7eKfnCsQtLDAWf_553XgrZXcBlj1aetsn8vKie9usDSIyL_zWKytmBLF8sWuxO-TXI47EbfxDTPdHpYw-bsl7KFFPu25-kB0/s1600-h/buffdimansion-1.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="388" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_fN4xf_LZaRFDQGQHgjwj1W7wDC2odnlqDm796KhusKU7eKfnCsQtLDAWf_553XgrZXcBlj1aetsn8vKie9usDSIyL_zWKytmBLF8sWuxO-TXI47EbfxDTPdHpYw-bsl7KFFPu25-kB0/s400/buffdimansion-1.jpg" width="400" /></a></div><ul></ul><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div>Unknownnoreply@blogger.com2tag:blogger.com,1999:blog-5963718918139647263.post-43937638089553393942010-02-08T00:13:00.000-08:002010-02-08T11:53:06.029-08:00Musiland Driver 1.082: Fast vs Precision<div style="font-family: "Trebuchet MS",sans-serif;">A reader sent me some measurements on the I2S lines with the latest driver. The first picture is with Fast Mode and the second picture is with Precision Mode. I think the error of 4 Hz is probably due to probe or calibration as the theoretical deviation in fast mode is 17 Hz (The measurement shows 21 Hz deviation)</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: "Trebuchet MS",sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKNzPgUYaiWCWVRzEHawf3Njj8z61K-Kw5AWTQ9tmAqlxDMw7MtmRalczbcBLy3S0n93KR-wYOoHzDzra4sGHsudRSCFIHesis8wQZwzOw-PWMGWg5H9s-XfAq19lCoU7SSxU8CXJPppM/s1600-h/44kHz_Fast.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="387" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKNzPgUYaiWCWVRzEHawf3Njj8z61K-Kw5AWTQ9tmAqlxDMw7MtmRalczbcBLy3S0n93KR-wYOoHzDzra4sGHsudRSCFIHesis8wQZwzOw-PWMGWg5H9s-XfAq19lCoU7SSxU8CXJPppM/s400/44kHz_Fast.jpg" width="400" /></a> </div><div class="separator" style="clear: both; font-family: "Trebuchet MS",sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4_iVh9Z-dwJ57SqeOLCWbXoubsmSVtN-1f_ZR9uJTct7EDYb3ePmU0DzDlyuBuJK-_7kK6gF_prU4MZ66AQF6dj7WEGK_l61LZ-SQmXe6hjzSuiBXm_y8HMLqwA_QX01uWMtKH2a-HNs/s1600-h/44Khz_Precision.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="367" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4_iVh9Z-dwJ57SqeOLCWbXoubsmSVtN-1f_ZR9uJTct7EDYb3ePmU0DzDlyuBuJK-_7kK6gF_prU4MZ66AQF6dj7WEGK_l61LZ-SQmXe6hjzSuiBXm_y8HMLqwA_QX01uWMtKH2a-HNs/s400/44Khz_Precision.jpg" width="400" /></a> </div><div class="separator" style="clear: both; font-family: "Trebuchet MS",sans-serif; text-align: left;">In addition, he measured the LRCK signal in an oscilloscope. The waveform looks very clean. Note: device is powered with an external low noise regulator (not USB power)</div><div class="separator" style="clear: both; font-family: "Trebuchet MS",sans-serif; text-align: left;"><br />
</div>96K Waveform<br />
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</div><div class="separator" style="clear: both; font-family: "Trebuchet MS",sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVm6BMyp_e_h0fdMJ0-M7BtwX9gAE2XD1lDL6kIcM7cJHAXsWbCFD3YlC_PBImO46rXwhov0cDJem1o0lem_S0dtKvl4SXX9nvxIerXt56dp9tb_JwSKZNub8Z_Ynrd37bGLXn8eCgyTI/s1600-h/96kHz_LRCK.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="358" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVm6BMyp_e_h0fdMJ0-M7BtwX9gAE2XD1lDL6kIcM7cJHAXsWbCFD3YlC_PBImO46rXwhov0cDJem1o0lem_S0dtKvl4SXX9nvxIerXt56dp9tb_JwSKZNub8Z_Ynrd37bGLXn8eCgyTI/s400/96kHz_LRCK.jpg" width="400" /></a></div><div class="separator" style="clear: both; font-family: "Trebuchet MS",sans-serif; text-align: left;">44.1K Waveform</div><div class="separator" style="clear: both; font-family: "Trebuchet MS",sans-serif; text-align: left;"><br />
</div><div class="separator" style="clear: both; font-family: "Trebuchet MS",sans-serif; text-align: left;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKxeeWOImQZw85D-nUpXxbbqd4Rd4IQRIclX73P1A2UMnqB21ZrGUA1TSWhjAfhN4Dm2j_GoYwUyJE-rPH_e-VVlTxM5_SxYf3fyJZeJLuJPqkOD7x3DRobxBdPxxAyzE1xLDo4EhyJiI/s1600-h/44kHz.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="358" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKxeeWOImQZw85D-nUpXxbbqd4Rd4IQRIclX73P1A2UMnqB21ZrGUA1TSWhjAfhN4Dm2j_GoYwUyJE-rPH_e-VVlTxM5_SxYf3fyJZeJLuJPqkOD7x3DRobxBdPxxAyzE1xLDo4EhyJiI/s400/44kHz.jpg" width="400" /></a></div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-5963718918139647263.post-21794694305912848342010-02-06T01:20:00.000-08:002010-08-06T12:28:25.605-07:00Programming the WM8804<div style="font-family: "Trebuchet MS",sans-serif;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0bEHMGKejK31uZXZa_rcKIBtSLRkqCeRhCeq3GSNRP0_j3DzV8j7beaw5D54NkaRIK3gK8se223hq-J0dLvWuN_Fbug44UMACVyJIQ_hF-hmJ9k9wwVN3I7R4NmSd3Ryg0GCNbsnrMoQ/s1600-h/wm8804.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="287" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0bEHMGKejK31uZXZa_rcKIBtSLRkqCeRhCeq3GSNRP0_j3DzV8j7beaw5D54NkaRIK3gK8se223hq-J0dLvWuN_Fbug44UMACVyJIQ_hF-hmJ9k9wwVN3I7R4NmSd3Ryg0GCNbsnrMoQ/s400/wm8804.JPG" width="400" /></a></div><br />
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I'm going to attempt to use the WM8804 SPDIF receiver in software mode. A quick look at the datasheet shows that there are 30 registers to program!. I've done an extensive search in the internet and there are no projects involving using this part in software mode. In fact, it seems it is not very easy to program.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">But first lets explore this device in a bit more detail.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">According to the manufacturer, the WM8804 has the lowest intrinsic jitter of any commercial spdif receiver. In addition, it provides large immunity against incoming jitter.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">Lets explore why the WM8804 is immune to incoming jitter.</div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
</div><div style="font-family: "Trebuchet MS",sans-serif;">Conventional spdif receivers utilize a PLL to lock into the signal. Devices such as the very popular CS8412/14/16 operate this way. A PLL generates an initial clock with a VCO (voltage controlled oscillator) and compares the phase of that clock with an incoming clock. The error in phase results in a voltage that is feed back to the VCO until the output clock "locks" unto the input clock. According to an <a href="http://www.audiocraftersguild.com/AandE/npt.on.jitter2.htm">AES paper</a>:</div><blockquote style="font-family: "Trebuchet MS",sans-serif;">Popular S/PDIF receiver chips like the Yamaha YM3623B and Crystal CS8412 are NOT crystal controlled but rather recover the necessary clock from internal Phase Locked Loops (PLL) locked onto the incoming data stream. The simple two pin can crystals often seen directly attached to '3623's and '8412's are optional. The 3623 uses the crystal clock to quickly lock onto the S/PDIF signal. The 8412 uses the crystal clock to determine and display the sample rate and jitter level of the S/PDIF signal. Both parts ignore the local crystal clock once locked onto the S/PDIF signal.</blockquote><div style="font-family: "Trebuchet MS",sans-serif;">Higher end parts will use a sample rate converter to further clean the jitter. Both TI and Cirrus have spdif receivers with built in ASRCs It is noted that the use of ASRC is controversial in high end audio (there are camps on both sides)</div><div style="font-family: "Trebuchet MS",sans-serif;"></div><div style="font-family: "Trebuchet MS",sans-serif;"><br />
According to Wolfson in their <a href="http://www.wolfsonmicro.com/documents/uploads/misc/en/A_high_performance_SPDIF_receiver_Oct_2006.pdf">white paper</a>: </div><div style="font-family: "Trebuchet MS",sans-serif;"><blockquote>The goal here is to <b style="color: #cc0000;">synchronize a clock generated from a PLL and high quality oscillator</b> to incoming S/PDIF data stream. This is different to usual approach of using a PLL to recover a clock from the S/PDIF data stream, which inherently has to track the jitter to maintain lock.</blockquote>The white paper gives the technical details, but suffice to say that it is essentially a PLL followed by a re-clocker (not a sample rate converter) with a time based derived from the crystal. I have a post comparing the difference between re-clocking and sample rate conversion <a href="http://hifiduino.blogspot.com/2009/06/asynchronous-re-clocker-vs-asynchronous.html">here</a>.<br />
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Measurements by Wolfson shows the WM8804 compared with another commercial part<br />
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The following picture shows the jitter performance of the WM8804 with incoming signal having 5UI of jitter injected in the input sdif signal (5UI is 5x163nsec for 48K sample frequency). Result: 51.7 psec (period jitter RMS) which is the same as the spec'ed intrinsic jitter of the device (50 psec)<br />
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The following picture shows the jitter performance of a competitive device spec'ed with 150 psec of intrinsic jitter. The result is 334psec (period jitter RMS)<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgolr1uAPwQg9M5HBKCApN9TIBi3eT9Ifba6rxjJtyPuKlxZPhUC_9MZcBD68IXb4jtEBfWgTG7Lu3p0Cl4oVb4OSBaFnLs-9nJvZi0HlXwmuF_xSARQkZqKtnDkIGiS2bjdAVT7bxwYVY/s1600-h/jitterOther.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgolr1uAPwQg9M5HBKCApN9TIBi3eT9Ifba6rxjJtyPuKlxZPhUC_9MZcBD68IXb4jtEBfWgTG7Lu3p0Cl4oVb4OSBaFnLs-9nJvZi0HlXwmuF_xSARQkZqKtnDkIGiS2bjdAVT7bxwYVY/s400/jitterOther.jpg" width="400" /></a></div><br />
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To be fair, 5UI of jitter which translates into 800 nsec which is a HUGE amount of jitter. The lowly Apple Airport Express was <a href="http://www.stereophile.com/digitalprocessors/505apple/#">measured by Stereophile</a> to have a "respectably low 258ps of jitter" in the spdif output. Thus in real life, I think the relevant measure is intrinsic jitter in which the Wolfson part excels at 50 psec<br />
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Here is the WM8804 Implementation by <a href="http://www.twistedpearaudio.com/digital/wm8804.aspx">TwistedPearAudio</a>:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGuppOozu5KmY3n8AHoxlwJqIydx2vb1ZEAMG2qI8VszjVqq_7__KI1LunVy7ZvDzn3XvJNjH6ZiNJqrgYHo6235B1xeAMxWaqYSpyxrkGBrHakt7byKlCuyINTJzVPkDR6AQh5paWaho/s1600-h/DSC_0339+%282%29.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="221" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGuppOozu5KmY3n8AHoxlwJqIydx2vb1ZEAMG2qI8VszjVqq_7__KI1LunVy7ZvDzn3XvJNjH6ZiNJqrgYHo6235B1xeAMxWaqYSpyxrkGBrHakt7byKlCuyINTJzVPkDR6AQh5paWaho/s400/DSC_0339+%282%29.JPG" width="400" /></a></div></div>Unknownnoreply@blogger.com6tag:blogger.com,1999:blog-5963718918139647263.post-59196429754621441282010-02-03T10:36:00.000-08:002010-02-03T10:40:56.544-08:00Musiland 01-US I2S Mod<span style="font-family: "Trebuchet MS",sans-serif;">A reader sent me a few pictures of his I2S Mod</span><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVmgSxV8x_rcC61CXuv9Lttw2eo4rM1cBv6GPRaFShhLjL0KVx4Hxf6lfdqRvgeHV9N26UGfZ1tvA9bFGlAgcRP7xKUjymh_aY1vPUZ8FmZydZOA9pecSTwgLvzmleWRADE24KT4bp9_o/s1600-h/DAC_MUSILAND_2.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVmgSxV8x_rcC61CXuv9Lttw2eo4rM1cBv6GPRaFShhLjL0KVx4Hxf6lfdqRvgeHV9N26UGfZ1tvA9bFGlAgcRP7xKUjymh_aY1vPUZ8FmZydZOA9pecSTwgLvzmleWRADE24KT4bp9_o/s400/DAC_MUSILAND_2.jpg" width="381" /></a></div><span style="font-family: "Trebuchet MS",sans-serif;"> </span><br />
<div style="clear: both;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_qDpGp1b0FqI8g1YQ61RWxZb3GwLu4It4X-aGFqpxpfeDVo0FB0c-UYHxgPoJkTd1vPyFN-1sBHIWD1ZsQM2PglvbJfqi_6HBiTljhoq4YW9AyMn1OCUV_RoTcUqvkhTx7WDUpbXdWD8/s1600-h/Musiland_I2S_TAP.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_qDpGp1b0FqI8g1YQ61RWxZb3GwLu4It4X-aGFqpxpfeDVo0FB0c-UYHxgPoJkTd1vPyFN-1sBHIWD1ZsQM2PglvbJfqi_6HBiTljhoq4YW9AyMn1OCUV_RoTcUqvkhTx7WDUpbXdWD8/s400/Musiland_I2S_TAP.jpg" /></a></div></div>Unknownnoreply@blogger.com2tag:blogger.com,1999:blog-5963718918139647263.post-19497004631121568862010-01-28T10:06:00.000-08:002011-07-08T12:23:44.714-07:00Clock generation in the Musiland Devices<div><span style="font-family: trebuchet ms;">Over at <a href="http://www.diyhifi.org/forums/viewtopic.php?f=2&t=1889&start=15">diyhifi.org</a>, user simmconn figured out how the clocks of the Musiland are synthesized (I've summarized here):</span><span style="font-family: trebuchet ms;"><br />
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</span><span style="font-family: trebuchet ms;">The Xilinx FPGA has two DCMs (</span><span style="font-family: trebuchet ms;">"Digital Clock Managers")</span><span style="font-family: trebuchet ms;">. They take an existing clock and perform integer multiplications and divisions in order to synthesize a new clock frequency. </span><span style="font-family: trebuchet ms;">The frequencies required to handle all the sample rates are</span><span style="font-family: trebuchet ms;">:</span><span style="font-family: trebuchet ms;"><br />
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</span><span style="font-family: trebuchet ms;"><span style="color: red;">24.576MHz</span> for 48KHz, 96KHz and 192KHz sample rate and</span><span style="font-family: trebuchet ms;"><br />
</span><span style="font-family: trebuchet ms;"><span style="color: red;">22.5792MHz</span> for the 44.1KHz, 88.2KHz and 176.4KHz sample rate</span><span style="font-family: trebuchet ms;"><br />
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</span><span style="font-family: trebuchet ms;">The ratios for the DCMs to generate the required frequencies are as follows:</span><span style="font-family: trebuchet ms;"><br />
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</span><span style="font-family: trebuchet ms;">22.5792 MHz = 48 MHz*(14/25)*(21/25)</span><span style="font-family: trebuchet ms;"><br />
</span><span style="font-family: trebuchet ms;">24.576 MHz = 48 MHz*(8/25)*(8/5)<br />
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</span><span style="font-family: trebuchet ms;">Since there are two sets of ratios, the Xilinx chip needs to change them on the fly </span><span style="font-family: trebuchet ms;">when sample rate changes (because the fpga used in the Musiland devices only has two DCMs).</span><br />
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<span style="font-family: trebuchet ms;">Simmconn determined that (the earlier version of the drivers did not have this reconfiguration on the fly capability and) fixed ratios were used in the DCMs. He figured that in order to generate the two frequencies with static DCM m/n numbers, they had to select 24.576 MHz and a frequency close to 22.5792 MHz:</span><br />
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<span style="font-family: trebuchet ms;">22.588235 MHz = 48 MHz*(8/17) -Using the first DCM</span><br />
<span style="font-family: trebuchet ms;">24.576 MHz = 48 Mhz X2 (using clock multiplier function of fpga) = 96 MHz; 96MHz*(32/25)= 122.88 MHz -Using the second DCM; externally divide by 5 using clock division of fpga.<br />
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</span><span style="font-family: trebuchet ms;">if we divide this frequency by 512 (you divide by some multiple of 64 which is sort of the minimum fs)</span>, we can calculate the resultant sample frequency:<br />
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<span style="font-family: trebuchet ms;">22.588235/512 = <span style="color: red;">44,117.6</span> Hz</span><span style="font-family: trebuchet ms;"> (Approximation)</span><br />
<span style="font-family: trebuchet ms;">24.576/512 = <span style="color: red;">48,000</span> Hz (Exact)</span><br />
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<span style="font-family: trebuchet ms;">I previously measured MCK from the I2S lines of the Musiland MINI model:<br />
<br />
For 44.1K Material:<br />
</span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgua7VqoZG1PMTxeSVPF6rgUCxyBCtMjb59ZV19TPtzFRGg8rl08bKvaotXbf2K7ETPpaOBJ8L2ffVTtj95jYP9DSF2gzWm2502Hti_hqo3LkLpCS20q1pb6mpVoDUQwxhutaJ6GAw2tg/s1600-h/P1020211.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" style="font-family: trebuchet ms;"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5431939092096673778" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgua7VqoZG1PMTxeSVPF6rgUCxyBCtMjb59ZV19TPtzFRGg8rl08bKvaotXbf2K7ETPpaOBJ8L2ffVTtj95jYP9DSF2gzWm2502Hti_hqo3LkLpCS20q1pb6mpVoDUQwxhutaJ6GAw2tg/s200/P1020211.JPG" style="cursor: pointer; height: 139px; width: 200px;" /></a><br />
<br />
<span style="font-family: trebuchet ms;">For 48K Material</span><br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJoVpI8a6tWuIMBCzkJC3dd4NFcKXuCO8_x3zrOhYChOvitOs4qLq4fmC0cs9EbQpqIP31HLaIFnhGeZySoisyJ4jCTNsv3-FkqLzhpw3McTauG5ouetKCwD9P3NivnwBX3w2_VxXz2ls/s1600-h/P1020208.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" style="font-family: trebuchet ms;"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5431939184350355714" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJoVpI8a6tWuIMBCzkJC3dd4NFcKXuCO8_x3zrOhYChOvitOs4qLq4fmC0cs9EbQpqIP31HLaIFnhGeZySoisyJ4jCTNsv3-FkqLzhpw3McTauG5ouetKCwD9P3NivnwBX3w2_VxXz2ls/s200/P1020208.JPG" style="cursor: pointer; height: 150px; width: 200px;" /></a><br />
<span style="font-family: trebuchet ms;"><br />
I also determined that fs was 128.</span><span style="font-family: trebuchet ms;"> If we use these numbers we determine that the sample frequency<br />
<br />
</span><span style="font-family: trebuchet ms;">5,647,218/128= <span style="color: red;">44,118.9</span> Hz which confirms the deviation from 44,000 Hz<br />
6,144,177/128= <span style="color: red;">48,001</span> Hz which confirms that the sample rate is exact.<br />
<br />
This was the way clocks were generated...</span></div><br />
<div><span style="font-family: trebuchet ms;"></span></div><br />
<div><span style="font-family: Trebuchet MS;"><b>A NEW DRIVER...</b></span></div><br />
<div><span style="font-family: trebuchet ms;">This week <a href="http://www.soomal.com/doc/10100001004.htm">Musiland released a new driver</a> that reconfigures the two DCMs when the sample rate changes, and generates two clocks with exact frequency to support the different sample rates</span><br />
<br />
<span style="font-family: trebuchet ms;"> </span></div><span style="font-family: trebuchet ms;">The driver has two Sample Rate Control modes:</span><br />
<ul><li><span style="font-family: trebuchet ms;">Fast Mode and Precision Mode. Fast Mode is like before: the DCMs are statically configured and the 44.1KHz family clock has a small error.</span></li>
<li><span style="font-family: trebuchet ms;">Precision Mode reconfigures the DCMs when there is change in sample rate family (e.g. from 44.1 to 48KHz) and the resultant clock is exact.</span></li>
</ul><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTx0wfREXd1tTh6ZfCuK0s27tRIjMAC_Zuca8eZHLfpEyroFo86MPCAFH_c7CzANrcyCY9XM9Gs9ZixPFW3Cnzrv-luSjKGdzk9Gymv98XKLmtzJ-6xn2MniiMT7ZDoPD_kAiJ_BZT3VI/s1600-h/musilandCP.jpg"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5432009098138717922" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTx0wfREXd1tTh6ZfCuK0s27tRIjMAC_Zuca8eZHLfpEyroFo86MPCAFH_c7CzANrcyCY9XM9Gs9ZixPFW3Cnzrv-luSjKGdzk9Gymv98XKLmtzJ-6xn2MniiMT7ZDoPD_kAiJ_BZT3VI/s400/musilandCP.jpg" style="height: 237px; width: 400px;" /></a><br />
<span style="font-family: trebuchet ms;"></span>Unknownnoreply@blogger.com7tag:blogger.com,1999:blog-5963718918139647263.post-36138819826203710702010-01-16T19:06:00.000-08:002010-01-18T13:38:09.975-08:00Enter raffle to support the people of Haiti<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRFoosYWs_i-Ql7tTe6VEoEOuMW6suz3WBrw8LVpivyQizdgGmzrcst1BjJXr9W-33JtywpoBWFtEFY2UiaFIthgOijdHigGeuWUvN6DZYWUV8jdKaLOmCUdC9rAu6Sv_Cp5p7aWpVv_k/s1600-h/haiti.jpg"><img style="width: 400px; height: 248px;" id="BLOGGER_PHOTO_ID_5427857284242474610" alt="" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRFoosYWs_i-Ql7tTe6VEoEOuMW6suz3WBrw8LVpivyQizdgGmzrcst1BjJXr9W-33JtywpoBWFtEFY2UiaFIthgOijdHigGeuWUvN6DZYWUV8jdKaLOmCUdC9rAu6Sv_Cp5p7aWpVv_k/s400/haiti.jpg" border="0" /></a><br /><span style=";font-family:lucida grande;font-size:78%;" >Photo copyright CNN</span><br /><br /><span style=";font-family:trebuchet ms;font-size:130%;" >Twisted Pear Audio is sponsoring a </span><a href="http://www.twistedpearaudio.com/relief/relief.aspx"><span style=";font-family:trebuchet ms;font-size:130%;" >raffle</span></a><span style=";font-family:trebuchet ms;font-size:130%;" > to support relief efforts in Haiti. Raffle will be held Wed January 20. Hurry! </span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-5963718918139647263.post-30094691700625841772010-01-01T10:58:00.000-08:002010-01-01T11:13:06.844-08:00Happy New Year!!!<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh74QKPxyDyDNDXztmD_wqs0X8hv0zfpxng-1Nj2fgse9SI2Jv0dxHZSyOKJc2BgBLfihWD29SPoe8UiQJ2pfZ1ZPWkD7XwNd6OKA9yzMlA9x64nQJQXIT7qekuejMX_rAHEm0suwZcYn4/s1600-h/DSC_0324+%283%29.JPG"><img style="cursor: pointer; width: 400px; height: 267px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh74QKPxyDyDNDXztmD_wqs0X8hv0zfpxng-1Nj2fgse9SI2Jv0dxHZSyOKJc2BgBLfihWD29SPoe8UiQJ2pfZ1ZPWkD7XwNd6OKA9yzMlA9x64nQJQXIT7qekuejMX_rAHEm0suwZcYn4/s400/DSC_0324+%283%29.JPG" alt="" id="BLOGGER_PHOTO_ID_5421851065216762850" border="0" /></a><br /><span style=";font-family:trebuchet ms;font-size:78%;" >Before...</span><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFtJABaQBXe5BaIh_lw0Mf910Hy5wWyuofT7nPw1MLTeiLrAOFDgbad7dvXJ_z5-bw_xbIagQg-8rgkxVWgWwTi0-oHc0uhY5riZ9pUyk32SW1xbc0XZ1qWTdidCUR5BJfZ466ORI0kFM/s1600-h/before.JPG"><img style="cursor: pointer; width: 400px; height: 261px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFtJABaQBXe5BaIh_lw0Mf910Hy5wWyuofT7nPw1MLTeiLrAOFDgbad7dvXJ_z5-bw_xbIagQg-8rgkxVWgWwTi0-oHc0uhY5riZ9pUyk32SW1xbc0XZ1qWTdidCUR5BJfZ466ORI0kFM/s400/before.JPG" alt="" id="BLOGGER_PHOTO_ID_5421849573180843970" border="0" /></a><br /><br />May this new year bring lots of joy to you and your families!Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-5963718918139647263.post-5572802109743684802009-12-30T23:55:00.000-08:002009-12-31T00:10:59.771-08:00I2S LRCK Trace<span style="font-family:trebuchet ms;">Decided to measure the LRCK line again to see if the waveform was cleaner.<br /><br />The picture speaks for itself. See the trace before <a href="http://hifiduino.blogspot.com/2009/12/here-is-measurement-when-itunes-plays.html">here</a>.</span><br /><br /><div style="CLEAR: both"><a href="http://picasa.google.com/blogger/" target="ext"></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizvV0pyOcIoSHLJhJTEsgWX9n5ki-r3aoE0sHTC5eLmPkkFoPdLBIGw67FT7sUpGBzoEB-4kTLT90FgtxJonbCYRFwz3dgi9hpLDAjMzzs3FXQhkX05TurZbdwSBXDKaceNfawq1x8_dM/s1600-h/P1020416.JPG"></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCB5dta8Brnm53gc_FARGWwvAB34la7RKZTrtN0ZjKbrZZ5JtVXDtxIaR4F0bzO9Fo4PJxqkXfsOtYQnV0A0-YM9T-TvbKneZrH3OUkuy5J5vKkTOeR7WFc1PavBxYV5dpTOvGuhy_d3s/s1600-h/P1020417.JPG"><img style="WIDTH: 400px; HEIGHT: 264px; CURSOR: hand" id="BLOGGER_PHOTO_ID_5421309557501234610" border="0" alt="" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCB5dta8Brnm53gc_FARGWwvAB34la7RKZTrtN0ZjKbrZZ5JtVXDtxIaR4F0bzO9Fo4PJxqkXfsOtYQnV0A0-YM9T-TvbKneZrH3OUkuy5J5vKkTOeR7WFc1PavBxYV5dpTOvGuhy_d3s/s400/P1020417.JPG" /></a></div><br /><div style="CLEAR: both"></div><br /><div style="CLEAR: both"></div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-5963718918139647263.post-55712049333383910812009-12-30T22:36:00.000-08:002010-01-26T10:24:17.422-08:00Reducing sources for noise<span style="font-family:trebuchet ms;"><a href="http://www.audioasylum.com/forums/pcaudio/messages/6/66891.html">Elsewhere </a>it has been measured that the DC-DC converters are a potential source for noise. Because I am not using the headphone output, I decided to cut the traces to these DC-DC converters. It is only required to cut two traces which you can later jumper if you decide to reverse the changes.</span><br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivZUrGVws3PM3TZMqZULi3h6aR25HegRSlyWIfsgYZoJMlvBBOX3QOAuCyMZHA3mKceHnjbUWkEZv-AeBMxWXRWMOwAXXE9ztoHwHnwwNwJHU-7U7Y21bdQHSrXMzHXLtKMNxttMOqEZY/s1600-h/P1020415.JPG"><img alt="" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivZUrGVws3PM3TZMqZULi3h6aR25HegRSlyWIfsgYZoJMlvBBOX3QOAuCyMZHA3mKceHnjbUWkEZv-AeBMxWXRWMOwAXXE9ztoHwHnwwNwJHU-7U7Y21bdQHSrXMzHXLtKMNxttMOqEZY/s400/P1020415.JPG" border="0" /></a><br /><br /><br /><br /><span style="font-family:trebuchet ms;">Power to the second DC-DC converter goes through a trace on the underside of the board</span><br /><br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBxA7CqUddkO-hyOikm4lEAEihpaz1-ZKN3NfExzTj77K6OE_nQ8jGvtZpL-JCsEN2kzA1AracFMBQ5Y7FWi7-fTFSmkDM1MerWwLgDf-ix6BXH2ZGJvkGuPkBSol1da3e7smukbSmc2g/s1600-h/P1020408.JPG"><img style="width: 400px; height: 385px;" id="BLOGGER_PHOTO_ID_5421287018680720418" alt="" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBxA7CqUddkO-hyOikm4lEAEihpaz1-ZKN3NfExzTj77K6OE_nQ8jGvtZpL-JCsEN2kzA1AracFMBQ5Y7FWi7-fTFSmkDM1MerWwLgDf-ix6BXH2ZGJvkGuPkBSol1da3e7smukbSmc2g/s400/P1020408.JPG" border="0" /></a><br /><br /><span style="font-family:trebuchet ms;">If you are using a different Musiland model, the traces will be in different places. But the procedure is as follows:</span><br /><br /><span style="font-family:trebuchet ms;">1- Identify the DC-DC converters. These are the 8-pin chips marked "3063". You can find the datasheet for these DC-DC converters </span><a style="font-family: trebuchet ms;" href="http://www.onsemi.com/pub_link/Collateral/NCP3063-D.PDF">here</a><span style="font-family:trebuchet ms;">.</span><span style="font-family:trebuchet ms;"> (There are two of them)</span>.<br /><br /><span style="font-family:trebuchet ms;">2- Identify the Vcc pin:</span><br /><br /><a style="font-family: trebuchet ms;" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhw_AS-Yte-cAwDPHZiJUAQXjhPv98QUPbBvQZKWs2GvNffr-DQ0lFAwTEerH_xcFTsTZMgFzbktHcQL0AA8sayzBeQNemMTYQ_fV3Dr-j1AYDCYcRclBjrjapeyFDNKb1uIwwYghP8IEo/s1600-h/dc-dc.jpg"><img style="cursor: pointer; width: 132px; height: 189px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhw_AS-Yte-cAwDPHZiJUAQXjhPv98QUPbBvQZKWs2GvNffr-DQ0lFAwTEerH_xcFTsTZMgFzbktHcQL0AA8sayzBeQNemMTYQ_fV3Dr-j1AYDCYcRclBjrjapeyFDNKb1uIwwYghP8IEo/s400/dc-dc.jpg" alt="" id="BLOGGER_PHOTO_ID_5430821033191249714" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjnybGHb6TD7gMcj8Ac-2IS-uJmKA-09LnUETUBlpvhGbiWgIsk2Pw8m8mdmA7bn19YQwtRuqSQEaWennM5ZgX3xsRgYmV93EA_0OY5va0-4mMJWBq7gLJArPh7Aqivi2LZkbbq8erlrb0/s1600-h/01-us5.jpg"><img style="cursor: pointer; width: 156px; height: 114px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjnybGHb6TD7gMcj8Ac-2IS-uJmKA-09LnUETUBlpvhGbiWgIsk2Pw8m8mdmA7bn19YQwtRuqSQEaWennM5ZgX3xsRgYmV93EA_0OY5va0-4mMJWBq7gLJArPh7Aqivi2LZkbbq8erlrb0/s400/01-us5.jpg" alt="" id="BLOGGER_PHOTO_ID_5431114261758670786" border="0" /></a><br /><br /><span style="font-family:trebuchet ms;">3- Find the trace that feeds this line and cut. This line also connects a local resistor and capacitors for the DC-DC converter. It may not matter whether you cut before the local cap or after the local cap, but in my mod I cut it before the local cap</span>.<br /><br /><span style="font-family:trebuchet ms;">4- Make sure you don't cut the line in a place that feeds the other linear regulators (there are two other linear regulator that feeds off the same lines - there are several traces but they all connect to the 5V USB power). In the second picture you can see the line (next to the crystal) that feeds both the DC-DC regulator and the linear regulator. It branches off and feeds the DC-DC regulator through a bridge underneath the board.<br /><br />5- If you plan well, you can actually use external wiring and a switch to reconnect the traces. This will re-enable the local analog output in case you feel like using the built-in headphone amp.<br /></span>Unknownnoreply@blogger.com8tag:blogger.com,1999:blog-5963718918139647263.post-67880234826885130642009-12-10T09:26:00.000-08:002010-11-30T22:13:16.281-08:00MUSILAND SPDIF to OPUS DAC (WM8804/WM8741)<span style="font-family: trebuchet ms;">Because the MCK for the Musiland devices is 128fs which is "not supported" by the WM8741 DAC (see previous post), I decided to use the SPDIF output of the Musiland to the TwistedPearAudio Wolfson WM8804 spdif receiver board and then to the WM8471 DAC board. With this configuration each component is working at its optimal range. 44.1KHz material goes to the DAC as 44.1KHz material and the DAC can apply high up-sampling allowing it work at its optimal range.<br />
<br />
</span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkrPAkKuZFIdFVGV0mpFZJO3n8H1T1FexRvYfqC34KRVEF4R6Bqpae57ZOHbuA8M8LXGgs-0FU3aGKm8tP80JvkDMhzARU0Ojc27f3nOZyhucgOGDpenE1wyyWhTyI9Mk2PtlPf6vtkas/s1600-h/DSC_0299.JPG"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkrPAkKuZFIdFVGV0mpFZJO3n8H1T1FexRvYfqC34KRVEF4R6Bqpae57ZOHbuA8M8LXGgs-0FU3aGKm8tP80JvkDMhzARU0Ojc27f3nOZyhucgOGDpenE1wyyWhTyI9Mk2PtlPf6vtkas/s400/DSC_0299.JPG" /></a><br />
<br />
<span style="font-family: trebuchet ms;">The Musiland 01-MINI has SPDIF out, but it is not connected to an output plug. However, all you have to do is install a resistor and connect the cable to the back side of the board.</span><span style="font-family: trebuchet ms;"><br />
<br />
Install resistor in R22 position as shown in picture</span><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWiMjkLY744PqaZbxI8dDthE_SEtYC197sEydDzmUQciiKh8lQIDgOKdPKrgQsFXoBrKol_SsujlcJ-V98dgM09PCOBQzkItbn7MDYRM75pC9ozJhjiiNiUD0k2pVwRNWGM9hKLsQEh4o/s1600-h/DSC_0303.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5413671192508915874" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWiMjkLY744PqaZbxI8dDthE_SEtYC197sEydDzmUQciiKh8lQIDgOKdPKrgQsFXoBrKol_SsujlcJ-V98dgM09PCOBQzkItbn7MDYRM75pC9ozJhjiiNiUD0k2pVwRNWGM9hKLsQEh4o/s400/DSC_0303.JPG" style="cursor: pointer; height: 248px; width: 400px;" /></a><br />
<br />
<span style="font-family: trebuchet ms;">Connect cable to backside of board</span><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-7GNGgcBxqYceAKq8lgKKK7hCV8aEvwOBvW8Ase5M8BQZHE697f_Zb1z1Y7PjgU_BhB0cTKTqdvRrvH-KvqKFOPd5TFiVDk3tyAeZanAlSr3Wa9mDWarut6kyB0zg1P6bALzKhMEsV50/s1600-h/DSC_0307.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5413671072259172786" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-7GNGgcBxqYceAKq8lgKKK7hCV8aEvwOBvW8Ase5M8BQZHE697f_Zb1z1Y7PjgU_BhB0cTKTqdvRrvH-KvqKFOPd5TFiVDk3tyAeZanAlSr3Wa9mDWarut6kyB0zg1P6bALzKhMEsV50/s400/DSC_0307.JPG" style="cursor: pointer; height: 308px; width: 400px;" /></a><br />
<br />
<span style="font-family: trebuchet ms;">NOTE: I use 221 ohm - in theory, this resistor is a voltage divider with the input 75 ohm resistor you find in spdif receivers in order to bring the level down to <a href="http://en.wikipedia.org/wiki/S/PDIF">.5v-1v</a> or so for "consumer spdif". I also didn't bother with impedance matching, transformer isolation and other "audiophile" concerns as the spdif wire is just a few inches long. I did use a coax that I scavenged from a cheap RCA interconnect cable</span><br />
<br />
<span style="font-family: trebuchet ms;">Some traces of the spdif signal <a href="http://www.head-fi.org/forum/thread/443786/musiland-monitor-02-us/435#post_6387575">here</a>. (Monitor US 02, but the chips are the same as the mini)</span>Unknownnoreply@blogger.com13tag:blogger.com,1999:blog-5963718918139647263.post-47740458858091244912009-12-10T00:16:00.000-08:002009-12-10T00:17:47.902-08:00Musiland I2S Connection to WM8741 DAC<span style="font-family: trebuchet ms;">From the MCK compatibility chart we can see that for 44.1 KHz sample rate, 128fs is not supported in the Wolfson WM8741. But I wanted to try it anyway. (Recall that the <a href="http://hifiduino.blogspot.com/2009/12/measuring-master-clock-and-fs.html">Musiland output MCK is at 128fs</a>)</span><br /><br /><span style="font-family: trebuchet ms;">It actually works and sounds well. However, when switching through the different internal upsampling options, only medium upsampling and no upsampling work. High upsampling does not work.</span><br /><br /><span style="font-family: trebuchet ms;">This means that the DAC is not working optimally. Perhaps using spdif rather than I2S is a better option for this DAC (Notice from the table that the BB DACs support 128fs with all sampling frequencies)</span><br /><br /><div style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8-8HCkFVsQrUgm4i851jgJUtPFQc1tVOgaERQKCH8Q2PVGJhFGp_HW-H9ryZ91qaDK9qk-dIj70faXYoR2Qm9HL2nTInxzQNP4Pll1FV5UpbGP2IV8vI0oFHf3JAY0BP5oXDYv8mCrqw/s1600-h/P1020198.JPG"><img alt="" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8-8HCkFVsQrUgm4i851jgJUtPFQc1tVOgaERQKCH8Q2PVGJhFGp_HW-H9ryZ91qaDK9qk-dIj70faXYoR2Qm9HL2nTInxzQNP4Pll1FV5UpbGP2IV8vI0oFHf3JAY0BP5oXDYv8mCrqw/s400/P1020198.JPG" border="0" /></a></div>Unknownnoreply@blogger.com3tag:blogger.com,1999:blog-5963718918139647263.post-1158723828019675262009-12-07T12:02:00.000-08:002009-12-07T12:07:10.082-08:00Master Clock Compatibility<span style="font-family: trebuchet ms;">I've compiled the supported MCK for different DACs. One can see that measuring the ouput MCK from a source device like the Musiland is important in order to determine its compatibility with a particular DAC.</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-YcVRtZK461rrG4wJnNQDr2zPRHtd9wqaeqK-Fz-PN2dPKwVSoJIPFMU7soINOH0sTw_BxkfLaVcOCncWGBqhzMPticHLzhrxgRrY65nR5vSrNbCD_JqrNlTzuC3PZOR23rolH4zpR3k/s1600-h/SampleRate-2.jpg"><img style="cursor: pointer; width: 177px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-YcVRtZK461rrG4wJnNQDr2zPRHtd9wqaeqK-Fz-PN2dPKwVSoJIPFMU7soINOH0sTw_BxkfLaVcOCncWGBqhzMPticHLzhrxgRrY65nR5vSrNbCD_JqrNlTzuC3PZOR23rolH4zpR3k/s400/SampleRate-2.jpg" alt="" id="BLOGGER_PHOTO_ID_5412587588275703650" border="0" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDT3oZ05YfjCOy7GPOJtyvBezc-CCPu82qitB4DLLpSW7WvPuzkD34HaOfSXsrCC87Xz3u2_VWzwvP31t2xvzQH07C54WH4MfCJcqDM43Uz6Na5bsr5alTP_HWheWGmOUjihTVT6sBm-0/s1600-h/SampleRate.jpg"><br /></a><div style="clear: both;"><a href="http://picasa.google.com/blogger/" target="ext"><br /></a></div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-5963718918139647263.post-67342749076716646942009-12-05T14:02:00.000-08:002010-05-12T14:50:00.348-07:00Measuring BCK (Bit clock)<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxSkHe4cyP-z0KtUOJjmhKFF2-ShyphenhyphenDwrLwxQ7RACQaeCEjZ4QlHuTL1X5SGhbELnZiLAS6L1JE4px5khOgmCT5uFsSJoEqtdOCW0DSUMVolutbTdL8ny_kfE0fmm1bOGfrroA6FCCENRc/s1600-h/P1020212.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5411875970462412002" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxSkHe4cyP-z0KtUOJjmhKFF2-ShyphenhyphenDwrLwxQ7RACQaeCEjZ4QlHuTL1X5SGhbELnZiLAS6L1JE4px5khOgmCT5uFsSJoEqtdOCW0DSUMVolutbTdL8ny_kfE0fmm1bOGfrroA6FCCENRc/s400/P1020212.JPG" style="cursor: pointer; height: 241px; width: 400px;" /></a><br />
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<span style="font-family: trebuchet ms;">So far we've measured two out of the 4 lines when using I2S. Strictly speaking, I2S only has 3 lines, but the Master Clock line is required by the DAC and some component generates the master clock.</span><br />
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<span style="font-family: trebuchet ms;">So we've measured MCK, LRCK and now we measure BCK. The data line cannot be measured because it varies with the data and it is a bit pattern corresponding to the data. So with these 3 measurements, we can characterized the I2S interface.</span><br />
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<span style="font-family: trebuchet ms;">For 44.1KHz material, we measured 2.8236 MHz. What does this mean? 28236/441=64.0. The BCK is running at 64 times the sampling rate or 64fs. This means that the device sends 32-bit words per channel (yes 32 bits of data per channel).<br />
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BCK can be 32fs (16 bit -16-bitx2), 48fs (24-bit per channel) or 64fs (32-bit per channel as it is in our case). DACs data sheet specify the word length it can accept, but since the send and receive bit depth do not have to match, words are either padded or truncated if there is a mismatch. </span><br />
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<span style="font-family: trebuchet ms;">From Wikipedia:</span><br />
<blockquote>If the Transmitter is sending 32 bits per channel to a device with only 24 bits of internal precision, the Receiver may simply ignore the extra bits of precision by not storing the bits past the 24th bit. Likewise, if the Transmitter is sending 16 bits per channel to a Receiving device with 24 bits of precision, the receiver will simply Zero-fill the missing bits. This feature makes it possible to mix and match components of varying precision without reconfiguration.</blockquote>This is possible because data is transmitted MSB first.Unknownnoreply@blogger.com3