Joemeek VC1

[Eliani]

Hi guys,

so I've got my friends VC1 on the workbench, his issue 50hz hum when phantom power turned on. He claimed to have put 220V on the device while it was stil set to 110V (switch by turning the fuse around). So I'm left with the pieces.

I opened the shell and instantly replaced a couple of buldged capacitors. but further there was no visual damages.

Now the hum is still there when turning on the phantom power switch. Voltage on the mic is 41.7V on both pin 2 and 3.
But I've noticed another problem, in the enhancement circuit the potmeters make a lot of noise, hizz and what not... but the switch to enable the enhancment circuit can actually be heard, and not a pop or crack, bu the actual fysical noise of the switch... as if there were a microphone inside the case to pick up that noise!!

I'm strangely wondering how this could be...,

 

[Eliani]

After installing a new LM7815 and changing out a burned smd rectifier I noticed that the acoustic handling was mor audible around the input transformer... Is there a way that something is broken in the input transformer?

when I tap the side of the case, with no microphone plugged in I can actually hear the tapping....!?
Inductance microphone or something like that?

 

[PRR]

Use a chopstick to poke inside, narrow-down the "microphone" to a single part.