Annoying Buzz From Guitar Rig

[Cam Khao]

Hi folks,

Ever since I bought my guitar rig over to Thailand last year, I have had this really annoying problem, and I cannot think of a way to fix it.

OK, let me explain the setup, it's pretty basic.

Guitar amp, plugged in to non-earthed (and I think this is what is causing the problem) mains socket. External multi-effects pedal (running on batteries) plugged in to amp. Guitar plugged in to multi-effects pedal.

Every time I switch on an effect that ups the gain (such as fuzz or overdrive), I get massive amounts of buzz and hum coming from the amp. Other effects cause this to a much lesser degree.

Now, if I plug the guitar direct in to the amp, then problem at all, no buzz or hum.

I never had this problem with the same rig when it was in the UK.

Am I right i thinking its the lack of an earth connection here that's causing the problem? Any suggestions how to fix this without an earth connection? As I play in quite a few places, most don't and won't have earthed power.

[SoiBiker]

First off I'd try different cables to eliminate them as a cause.

[Cam Khao]

First off I'd try different cables to eliminate them as a cause.

Already tried all new power cables, sound cables, and every variation of every type possible. It made no difference.

[CharlieH]

I'm no electrician, but have you considered that the voltage and amps are both inconsistent and lower than the UK. 220v =Thailand 240v = in UK

you may find this article of help: http://www.psaudio.com/ps_how/how-to-find-and-fix-hum/

[SoiBiker]

My next suspect would be the jack sockets on the guitar and multi fx.

[Cam Khao]

Jack socket in guitar is fine, works perfectly jacked direct in to the amp. It's definitely something weird with the stomp box. Or maybe its just that higher gain levels show the problem more.

[Cam Khao]

I'm no electrician, but have you considered that the voltage and amps are both inconsistent and lower than the UK. 220v =Thailand 240v = in UK

you may find this article of help: http://www.psaudio.com/ps_how/how-to-find-and-fix-hum/

The only thing plugged in to the mains is the amp. It's a Fender amp that operates at a pretty wide voltage range. What might be worth trying though, is getting a 220v power supply. It has an external power supply, so this should be easy. It might be the amp is fine with 220v, but the power supply is not. Good idea, thanks.

EDIT: Doh! The PSU is of course supplying the amp with DC power at 12v. So the amp doesn't are about the mains voltage. Sorry, it's late and my brain is fried.

Edited November 14, 2015 by Cam Khao

[Crossy]

The lack of an earth is the main suspect, have you tried rigging up a ground?

It doesn't have to be a very good one, balcony railings often work if you can't get a rod in somewhere.

[NanLaew]

In the UK, the stomp box would typically be grounded via the outer shielded (screen) wire of the audio connections to the amp chassis and ultimately to the grounded wall socket. Pursue Crossy's advice on somehow grounding the amp. Not sure how this will work in different locations though. If the power supply mains plug is 2-pin, try reversing the connection (unplug, rotate 180 degrees and plug back in again).

[Cam Khao]

I have suspected it to be a lack of grounding that is the problem all along.

The PSU mains plug is a 3 pin. Maybe I could rig some kind of fly lead from the ground pin to something like a balcony railing as suggested.

Thanks guys.

[SoiBiker]

The lack of an earth is the main suspect, have you tried rigging up a ground?

It doesn't have to be a very good one, balcony railings often work if you can't get a rod in somewhere.

I've wondered myself if a balcony railing would work as a ground. Is there a simple way to test if they're connected to ground?

[Crossy]

The lack of an earth is the main suspect, have you tried rigging up a ground?

It doesn't have to be a very good one, balcony railings often work if you can't get a rod in somewhere.

I've wondered myself if a balcony railing would work as a ground. Is there a simple way to test if they're connected to ground?

The railings are often welded to the building steel, so can provide a very good ground.

Use your meter to measure the voltage between the railing (scrape off the paint first) and the live side of an outlet, if you get about 220V go to the next step.

Obtain a conventional light bulb, about 15 Watt. Connect one side of the bulb to the live and carefully dab the other side onto your railing (ensure no-one is touching the railing, just in case). If the bulb lights (or your RCD trips) the railing is a decent earth.

[SoiBiker]

Thanks for the tip!