Reducing sources for noise

Elsewhere 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.





Power to the second DC-DC converter goes through a trace on the underside of the board




If you are using a different Musiland model, the traces will be in different places. But the procedure is as follows:

1- Identify the DC-DC converters. These are the 8-pin chips marked "3063". You can find the datasheet for these DC-DC converters here. (There are two of them).

2- Identify the Vcc pin:



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.

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.

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.