Mackie SRM350 v3 digital whine

Thread Starter

Alexwfm

Joined Mar 10, 2021
10
Hello,

I have a constant whining sound coming from this Mackie speaker, it sounds like digital whine and it does briefly change tonality when cycling through the different DSP modes (PA, DJ, Monitor etc..). Also the constant hiss that goes with the whine changes in EQ while changing modes.

The speaker has an AMP/Power supply board and a separate input board with the DSP and controls.

Disconnecting the DSP board gets rid of the whine besides some general hiss which is because of the high impedance at the amp input. This I'm assuming would be enough to isolate the problem to the DSP section, if it wasn't that it gets +-15v from the amp module.

Anyway I've removed the last OPAMP before the ADC and the sound still persist, also this sound wasn't affected by the input knobs which means it might be a problem later down the line.

Before going to swap every single electrolitic cap, is anything else which might be worth to try/check?

Thank you in advance.
Cheers,
Alex
 
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