Noise issues with FX and amp in same 10 gang

surfguy13

Hi guys

I rarely use pedals so when I get a problem I'm stuffed. 

Last night I set up a boost pedal and a trem pedal, powered via a power brick.....guitar into boost, patch lead between boost and trem and out of trem directly into a Marshall Superbass head.  Leads are all good as is head/cab.  The head and power brick were plugged into the same 10 gang which was not overloaded.

As soon as I flicked the power switch on the amp I got a loud'ish buzz, sort of mains buzz.  Assumed this was my crap wiring so changed power brick for 9v adaptors and changed leads.  Same thing.  Messed about for ages but no joy.

I then removed the power brick from the 10 gang that the head was plugged into, plugged it into another gang running from another socket altogether and........perfect.  No buzz, no noise at all.  Eh?  Any ideas?

ICBM

Sounds like a fault in the 10-gang... like no earth connection.

The alternative is that the Power Brick has the DC output earthed when it shouldn't be, but that the 10-gang or the other extension is still faulty and is acting as an (incorrect) earth lift. If this is the case you need to get *both* things fixed.

Try plugging both units into the other extension - if you get no buzz it's the original 10-gang that's faulty, if you do then the Power Brick probably has a grounded DC output.

surfguy13

ICBM said:

Sounds like a fault in the 10-gang... like no earth connection.

The alternative is that the Power Brick has the DC output earthed when it shouldn't be, but that the 10-gang or the other extension is still faulty and is acting as an (incorrect) earth lift. If this is the case you need to get *both* things fixed.

Try plugging both units into the other extension - if you get no buzz it's the original 10-gang that's faulty, if you do then the Power Brick probably has a grounded DC output.

Really helpful advice, many thanks. 

I don't think it's the power brick as, once plugged directly into the wall it was 100%.  However, I will do as you suggest to try and get to the bottom of it.  I'll hook everything up to another 10 gang and see if the fault is replicated.  Fingers crossed it's a dodgy earth on the gang!

surfguy13

Just thought I'd report back to say that I followed ICBMs advice and installed another 10 gang and........no more noise!!!  So it was the gang after all.  I just assumed it was the pedals.

Is there any way to work out what exactly is wrong with the other gang?  ICBM suggested that the gang might not have an earth connection.....is this simple to identify/fix?