On the VM209 (MM209) mono amp (and also on the stereo VM210/MM210) there is a ‘shutdown’ jumper. The used chip has an active low input (/SD). I guess the jumper delivers a +V to that input, which is probably pulled down by a resistor. Unnumbered onthe VM209, I guess R6 and R7 on the stereo amp.
Does anybody have the real schematic of this VM209 board? I would like to drive shutdown from a µcontroller.
Dear DirkH,
You can put 5V to pin 2 of jumper (mute) (left side “marked with VELLEMAN”) to put the module active.
Circuit diagram can be downloaded here: https://velleman.bitrix24.eu/~FsCOq
Best regards,
Velleman Support
Sorry for the late reply, just to say thx, that is the info I needed. It works like a charm!