[sdiy] Odd Earth/Ground issues

[Justin Owen]

Hey all - I'm asking this one on behalf of a friend because it has us both stumped...

He uses a small DIY 555-based oscillator - kind of a maxed out Atari Punk Console thing. It's only very basic but it has worked without any problems for the past year.

It's built into a home-made metal case and runs off a 9-12 Volt DC adapter.

He recently took it to the US and while using it at one particular house he started having all sorts of Earth/Ground issues - basically just touching the case would cause all sorts of fluctuations in the sound/noise.

He went through all the standard troubleshooting steps - changed the power adapter, plug, leads, etc - they even set it up in a different room in the house.

Bizarrely - this particular house is full of musical kit that works just fine. The little sound box works just fine in every other house.

Would anyone like to take a shot at a possible cause for this?

Cheers,

Justin