Amp buzzing/humming when guitar pot at Zero...

welshboyo

Hi All,

Got a possible issue with my setup in as much it seems to introduce a hum/buzz when I reduce my guitar volume to Zero, if I bring it up ever so slightly I can almost "dial" it out.

I have a feeling its fx related (it actually sounds like an overcooked Fuzz pedal) and it is only yesterday I introduced a Cioks DC10 to the mix to get rid of other noises!!!!

Any ideas on what this is and how I can rid of it...

Tried it with Tele/Strat, haven't broken out the gig gun HB guitars yet..

neilrocks25

Bad valve, maybe a power valve?

ICBM

What amp is it?

It won't be a power valve, but it could be the first preamp valve. But that would only apply if you have all true bypass pedals, all off.

Have you tried it with the guitar straight into the amp? Did it do it before you got the new power supply?

welshboyo

Hi IC,

Bogner Shiva..

Been fiddling again and once I bypass all fx or hit the global bypass on my Looper it goes away and is deadly silent....which leads me to somewhere on the board of doom.......I really hope it isn't this Cioks supply as it wasn't cheap and was bought with "noise reduction" in mind...

But why would the volume pot on my guitar affect this noise, at full or half guitar volume there's no noise at all, just when the guitar volume is reduced to fully off does it introduce like a ticking/crackly noise...

ecc83

Is the Cioks power supply on a 3 core mains lead?

If so,

1) you might have an earth/hum loop.

2) They want shooting.

A simple test. Get the setup a'humming then pull the plug on the guitar and wrap it tightly in turkey foil. Hum stops? Dodgy guitar pot.

Hum continues? Earth loop.

Dave.

welshboyo

hmm..ok

Cioks on 3 core and I reckon hereth lie the problem....none of these problems pre-Cioks...

guitar pot at Zero, no ticking noise until I put my hand on the strings....with Strat and Tele..

Unplug guitar, hum goes away

ecc83

Ok well, I don't want to be too hard on Cioks without further information such as whether they carry the mains earth thru to the common wire on the power sockets but all the evidence point to that being the case.

I would have thought that a device intended to power GUITAR pedals which are surely going to fetch up plugged into a guitar AMPLIFIER which will almost certainly be EARTHED would be class ll insulated and earth free?

Not a lot you can do about it. Certainly you MUST NOT REMOVE ANY MAINS EARTHS!

Still, it is a weird one and I would get the guitar electrics checked out if poss.

Dave.

ICBM

The old Power Bank power supplies used to be bad for this as well. The reason was that they did not fit an insulating spacer between the voltage regulator tab and the heatsink, resulting in the DC ground being earthed. Bad practice… to save a penny or something.

welshboyo

Hmmm...does it with 2 of the Strats and the Tele but nothing else...must be the guitars then...

ICBM

welshboyo said:

Hmmm...does it with 2 of the Strats and the Tele but nothing else...must be the guitars then…

Are they star grounded?

(Most factory stock Teles aren't, if that helps.)

welshboyo

Well, one of them definitely needs looking at (the JV Strat), the Tele is stock Baja and the other Strat is a stock CP 50...

The CS Strat is as quiet as anything, so is the LP and the PRS and the MM.

ICBM

What pickups does the CS Strat have? Just curious, it shouldn't actually matter! Since they're entirely bypassed when the volume control is fully down. I do wonder if the ones with noise-cancelling pickups tend to be wired in a less 'vintage' way though…

welshboyo

Abby Handwound Custom Shop 60 pickups according to the spec sheet..aka normal Strat pickups LOL

ecc83

I will bet then that the pot track is not connected to the earthy end tag.

Dave.