Weird hum/noise through rig last night

guitarmangler

Played last night, at ‘soundcheck’ before starting, when plugging into my amp via a BB preamp I had a slight background rrrrrrrrrr noise, when pedal was engaged the nose went up to RRRRRRRRRRR.
Hmm.
Swap pedal to my tubescreamer,
RRRRRRRR.
Hmm.
Swap guitar.
RRRRRRRRR.
Hmmm.
 Change leads.
RRRRRRRRRR
Quickly try and unplug lights/plugs to see if that makes a difference (unplug the PA playing backing music, doh !) but no help, I ran out of time to find the fault as I sort out the PA and levels etc and leave my guitar last.
I ended up plugging direct into my amp and used my volume control to clean up (I play with quite a lot of gain) and there was no noise from the amp at all like this.

Any ideas? Pedals were powered by batteries (only one pedal at a time), amp was plugged into the wall (no extension lead or sharing of a multi gang). Leads were good. Gigged same setup last week and was no problem.
Band does use various led type lights and stuff which makes me think hmm, but didn’t have time to unplug them all. Bad wiring ? Why did the noise only present itself when I had two leads and a pedal?

gringopig

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Roland

We had the same in one pub we play at. It turned out to be faulty wiring in the pub’s ring main. We now test every power socket that we are likely to use before we set up.

ICBM

It sounds like noise being picked up directly by the guitar - the extra gain from the pedals will just amplify it. If the pedals were on batteries it’s not a power supply issue. Where the noise is coming from is the question - a switch-mode power supply is the most likely culprit, but it could be something in your gear (eg lighting) or elsewhere in the venue.

The only possible electrical fault would be if the socket the amp was plugged into wasn’t earthed. A plug-in mains socket tester with three LEDs will show up things like this and is something worth having for gigging in venues with potentially dodgy wiring...

guitarmangler

Thanks for the advice. I’ll buy a mains tester and take it with me to every gig from now on.
Is this one OK? 

Winner Mains Polarity Tester Plug https://www.amazon.co.uk/dp/B002QW3SL8/ref=cm_sw_r_cp_tai_bnNBEbMPY2QQW

It could have been our lights? But we’ve gigged with them all before and never has this problem. I tried to replicate the issue today at home but, nope. Quiet. Weird that there was no noise directly into the amp, but noisy with two leads.

ICBM

guitarmangler said:

Thanks for the advice. I’ll buy a mains tester and take it with me to every gig from now on.
Is this one OK? 

Winner Mains Polarity Tester Plug https://www.amazon.co.uk/dp/B002QW3SL8/ref=cm_sw_r_cp_tai_bnNBEbMPY2QQW

I think so, although that's not one I'm familiar with.

guitarmangler said:

It could have been our lights? But we’ve gigged with them all before and never has this problem. I tried to replicate the issue today at home but, nope. Quiet. Weird that there was no noise directly into the amp, but noisy with two leads.

It is a bit odd if you tested the leads, but it may have just been the extra gain from the pedals if it was OK with them turned off.

thomasw88

Hearing aid loop in the venue?

Had that before, and after spending about 1 hour replacing every thing in my rig during the setup/sound check turned out that the venue had a hearing aid loop on. got it switched off and voila all good!

guitarmangler

thomasw88 said:

Hearing aid loop in the venue?

Had that before, and after spending about 1 hour replacing every thing in my rig during the setup/sound check turned out that the venue had a hearing aid loop on. got it switched off and voila all good!

Ah, now that might be it. Venue was a social club. The pitch of the note coming out of the speaker was, I think, lower than usual single coil hum.

maltingsaudio

Loop system was my first thought on this too particularly if guitar was single coiled

Blackjack

A friend of mine had a similar problem at a gig.  Turned out to be something that the pub had plugged into a socket near his gear that had a transformer type plug which was getting picked up. Only found it after the gig! 

Phil_C

Blackjack said:

A friend of mine had a similar problem at a gig.  Turned out to be something that the pub had plugged into a socket near his gear that had a transformer type plug which was getting picked up. Only found it after the gig! 

I hate it when that happens!