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.
Install resistor in R22 position as shown in picture
Connect cable to backside of board
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 .5v-1v 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
Some traces of the spdif signal here. (Monitor US 02, but the chips are the same as the mini)
13 comments:
Brilliant glt,
Any differences in sound that you noticed between I2S & SPDIF from the Musiland into the Wolfson DAC?
Brief evaluations don't seem to show any differences. If there is any bias is probably technical: The I2S sounds very good, but the DAC is not performing at its very best due to the low MCK. With spdif, the DAC can perform at its best but there is the spdif conversion step.
Both solutions are very good.
Dear GLT/HIFIDUINO
I wonder if it is necessary or really do not make any difference when taping I2S lines from Musliand 01 US or Mini to leave the on-board PCM dac with the "power on it".
Can this have any influence on I2S signals. In this case transmitter is sending I2S signal to 2 devices 1-st on-board musiland PCM dac an 2-nd "external" dac. Reading on many forums long and .... threats regarding importance of SPIF cable lengths, transmission line effects, reflection coefficient and impedance matching I just wonder about this case. I2S is different than SPIDF. But as You show on Your great measurements of Musiland I2S we deal with MHz signals.
As I can understand in Your projects You did not remove on-board PCM dacs or try to cut I2S lines or cut the power from PCM.
Was this ever the issue in Your project ?
And If You would mind from Your experience is there any difference in digital I2S signals between Musiland Mini and 01US/USD. Mini is just enough to do the job, as we can see on Your projects, but are there any differences from "digital or driver side" that could make difference. Could You tell anything about this..?
And of cause I have to say that Your blog is great place.
Great regards for Your Work.
Greg/Rosendorfer
Greg,
I agree great site, full credit to Glt.
If I can add something here which may be relevant - I use a Musiland 01US from which I tap the I2S. I have used it with the PCM DAC powered on & now with it powered off but haven't noticed any gross difference. This was by no means a scientific test as I changed many other things also. It would seem logical to power down all chips that are not needed for I2S operation simply as a means to avoid possible PS pollution.
Greg, dweeb4,
Thanks for the nice words. I have not killed the power to the unused parts due to lazyness.
Elsewhere, there is evidence of noisy signals from the dc-dc converters, so I do plan on killing the power to the dac and op-amp. But I want to do the mods in a reversible manner.
In my system I've never heard any "dramatic" improvement from a single mod, and mostly I can't hear any difference. But sometimes, after a series of mod I can hear some good improvement, leading me to believe that an accumulation of good engineering mods will eventually lead to something audible. (I don't listen to a particular sound, but to the music in general, so maybe that's why often I don't hear any differences).
I don't think feeding two dacs with I2S is a problem as the inputs are typically high impedance inputs and do not heavily load the I2S outputs. Obviously the ideal case is to remove the internal DAC, but that's non-reversible or hard to reverse.
Regarding spdif reflection etc. I use a 2" cable and reflections become a problem only when the length of the cable is compartable with the wavelengh. In the case of spdif, I think that's tens fo feets. In any case, a reflection will be the equivalent of a ghosting signal and that should be audible (may even sound good ;-) ). The impedance mathing is for maximum transfer of power, and the way the resistors are configured is to be a voltage divider to the "correct" level. But the WM 8804 receiver seems to work with "any" voltage.
In general, anywhere you can lower noise is a good thing. So I think that in addition to cutting the traces that feeds the dc-dc converters one could replace the 3.3V regulator with a shunt regulator or some lower noise design. The 3.3V regulator feeds the usb controller which generates the master clock and this would benefit from cleaner power.
Have you guys used Arduino?
Dear Guys
What can I say I'm really amazed by Your attitude and Your will to share with others.
So If You wouldn't mind the question before I will start cutting the traces...
In my system right now I do use PCM1794 DAC feed by SRC4192 with TENTLABS clock.
SRC is feed from SPIDF and USB at PCM 2707.
Musiland is going to exchange old PCM 2707
But I would appreciate any advice if it would be better to leave the SRC with good CLOCK in the system /and stick with PCM being feed at constant rate 24/96 / or rather feed the DAC directly from Musiland having the option to get HiRes material feed at its unchanged rate to the DAC and eventually up-sampling of CD material in software player / cPlay on CMP PC / .
Feeding DAC directly from Musiland seems to be more “interesting” option but the issue is about Musiland's CLOCK that as far as I have learned is not the best one, but maybe it is absolutely good enough not to worry about it.
Any advices from Your side.
Best Regards
Greg
Hi Greg,
PCM1794 seems the ideal DAC for the Musiland because it supports 128fs for 44.1k material.
My preference would be to skip the SRC because there is no consensus as to whether it is a good thing or a bad thing. I think the opinions tend to disfavor rate conversion.
If you could use the bypass feature of the SRC (meaning don't do rate conversion, just reclock) then I would use the src. But to use the bypass you need two clocks into the src: one for the 44/1K family and one for the 48K family. What is the frequency of your clock?
Thus musiland -> i2s -> dac would be my recommendation. Focus on using short wires of equal length and then share with us.... Happy Tweaking in the New Year:-)
Dear Glt
Thanks for all the info.
I'm just sting on my Musiland with the iron on.
I will let you know the outcome in few days.
Once more thanks
and Happy New Year.
Greg
Hi
First Happy New Year
It took a while but finally I find some time to leave my comment on Musiland 01US on my setup.
So finally Musiland is powered from decent external power supply. And is feeding PCM1794 by I2S.
Results are amazing. My English is not good enough to write about sound but I never though that my setup can sound so good. This is something to be hear, definitely one of best and major changes done. And pleas note that before I had and SRC4192 with low jitter TENTCLOCK before my PCM1794. So I did not expected this level of improvement.
OK small remark , I feel that it should be sad to make things clear, that Musiland 01US as USB external sound card is not "7-th wonder" that is really able to power HD650 with audiophile quality. But It is absolutely amazing as USB2.0 PC Transport with DIY I2S capability.
Once more thanks to GLT for his great blog. And Musiland for this amazing small device.
Greg
Greg,
Wow!, very nice to hear you got some good improvement out this implementation. Congratulations!!!. If you post a link to a photo I'll write a post about your successful implementation. Thanks for sharing
Dear GLT
You are really pushing me …... and please be informed that my “set-up” is definitely not as nice and “good looking” as Yours and I really doubt that anyone would find it attractive to look at....
So ...
To make a picture I have to take my Musiland out of its enclosure where it have been very carefully secured as during my micro-soldering adventure I find out that my I2S wires are quite delicate and can disconnect when not secured.
I have soldered the I2S wires directly to the PCM1738 DAC as I find this to be the easiest thing. /Again thanks for Your excellent pictures/ .
So if I'm going to do this ...it would be nice to make some more changes hopefully for better .
And as I have seen in Your blog, you finally decided to cut the power to all unused parts of Musiland and go for cleaning it little. Something I had in my mind from the beginning…. so some advice with bit more explaining picture/drawing would be nice, /unfortunately this pictures I've found on Your blog did not make me confident enough, specially that I'm using 01US and in case of mistake I have to wait about 4-5 weeks for new one /.
And before I start to cut anything please send some comments if reducing the supplies and eliminating source for noise, according to your opinion had really such positive influence on sound. I can see the “scope pictures” and they should “tell more than thousand words” but still do You did not “sound” to be really convinced as this scope pictures “suggested” You should be....
And one more question regarding this issue.. do You have any plans to make something special about CLOCK, like changing for better one or maybe very special supply just for clock. This clock “upgrade” is still on my mind.
Or maybe it is better to hold on and wait for new Buffalo v2 …. any comments on this from your side.??
Greg
Greg,
I've updated my post on removing the power to the DC-DC converters. Let me know if that is enough. Regarding the sound, I have not done careful comparisons yet, but it can't be bad at all. Other people can hear immediate differences, but I can't.
Some late comment
Though you don't like SRC,
What do you think about inserting SRC for doubling sampling rate of 32, 44.1 & 48KHz/ 128fs for I2S?
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