VM100 - buzzing & popping

Kits Audio Hi Fi Projects
1

Hi,

I’ve just constructed my combo amp/speaker cab, using a Vellman VM100.

It’s been very difficult sourcing a Long Thread 47K Ohm potentiometer, which is required due to the cabinet being 15mm thick MDF. I’ve therefore had to buy separate potentioemters and cannibalise them to make the desired long thread 47K ohm pot.

However, I’m finding that there’s a very annoying buzz at either end of the pot. Yes, I could simply not turn it the full way up or down, but that doesn’t seem right to me.

The amp also makes a loud popping sound upon power on or power off.

Do you have any ideas / tips / guideance to help me eliminate these problems?

Many thanks,

Derrick

2

I solved the annoying buzz at either of the pot, by simply adding a 110 Ohm resistor in series to the two outer terminals of the pot.

However, I still have the loud popping sound upon power on or power off. I’ve been looking at anti-plop circuits (like an RC snubber), so might give that a try. But if anyone knows of any other methods I’d love to hear your thoughts.

Cheers!