Avoiding hum

[strophlex]

What are the best ways to avoid that hum and other noises get into the audio signal path?

I am building a box with filters (SSM2044) in it and I have realized both the cables connecting input and the cables connecting output pick up noise. I am using standard hook up whire with left signal, right signal and gnd twisted. Would it be better to use a shielded cable and send gnd through the shield? Any other tips?

[nILS]

Noise:

* Cheap switchmode PSU bad

* Short cables

* Audio cables not parallel or really close to data lines

* Shielded cable shouldn't make a big difference with low voltages, if you do give them a try, only gound the shield on the signal source side

Hum:

* Avoid ground loops

* Starwiring

[strophlex]

I guess I might have ground loops. And I think they might come from the connections between my MB6582 and the filter box.

The filter box contains PSU, AOUT_NG modules, SSM2044 modules and SSM2164 modules. Connections between the box and the MB6582 are:

PSU - (+12V, +5V and GND)

Expansion port - (link to AOUT_NG, 3 wires (GND and +5V omitted to avoid loops) and one digital out for bypass relay.

Audio - Audio jacks out from MB6582 connected to audio jacks in to the box (L, R, GND)

So there is a separate ground for each audio channel in addition to the PSU GND. Should I just cut the GND for the audio connection?

The same question arrises for the CV connections. GND is connected once more for each CV in addition to the power supply GND.

[TK.]

Since you are using a single PSU, you should prefer starlike wiring: all grounds connected from the ground output of the PSU

Best Regards, Thorsten.