Selective volume knob static? SOS HALP!!!

rollyfoster

Silver Supporting Member
Messages
18,448
the volume knob on my Kirn tele has a lot of static and whooshing when plugged into either of my tube amps. Guitar's barely over a year old so it's not an old pot by any means. In fact, I had a suhr T with humbuckers that did the same thing so it may not even be isolated to this one guitar.

Happens with different cables and with or without pedalboard. BUT if I'm plugged into the board and have a pedal turned on then it's fine. No scratching or anything.


However, if I plug it into my Yamaha THR10 it's completely silent. No scratching or anything.

Any ideas as to why this is happening solely with my tube amps? I figure if it's a problem with the volume pot it would happen on any amp including the THR
 
Last edited:

Husky

Member
Messages
13,455
the volume knob on my Kirn tele has a lot of static and whooshing when plugged into either of my tube amps. Guitar's barely over a year old so it's not an old pot by any means. In fact, I had a suhr T with humbuckers that did the same thing so it may not even be isolated to this one guitar.

Happens with different cables and with or without pedalboard. BUT if I'm plugged into the board and have a pedal turned on then it's fine. No scratching or anything.


However, if I plug it into my Yamaha THR10 it's completely silent. No scratching or anything.

Any ideas as to why this is happening solely with my tube amps? I figure if it's a problem with the volume pot it would happen on any amp including the THR
Tubes amps usually don't have a capacitor to block any DC. Any DC on a pot makes noise. Sometimes there can be a small amount of D.C. On the grid of the tube. You could try changing the first tube.

The effects is isolating you from this
 

rollyfoster

Silver Supporting Member
Messages
18,448
Tubes amps usually don't have a capacitor to block any DC. Any DC on a pot makes noise. Sometimes there can be a small amount of D.C. On the grid of the tube. You could try changing the first tube.

The effects is isolating you from this

Thanks John. So that would impact the guitar volume knob? The amp volume knobs themselves haven't made any noise.

It's weird it happens with 2 guitars and on 2 different amps...the Bella and a Swart, and both of them have done it after a tube swap. I actually had chalked it up to drier weather until yesterday when I realized it doesn't happen with the THR.

I'm wondering now if it may have something to do with the house wiring.
 

Husky

Member
Messages
13,455
Thanks John. So that would impact the guitar volume knob? The amp volume knobs themselves haven't made any noise.

It's weird it happens with 2 guitars and on 2 different amps...the Bella and a Swart, and both of them have done it after a tube swap. I actually had chalked it up to drier weather until yesterday when I realized it doesn't happen with the THR.

I'm wondering now if it may have something to do with the house wiring.
So there is nothing between the guitar and the amp ? Did they do it before the tube swap ? Feel free to PM or email.
 

rollyfoster

Silver Supporting Member
Messages
18,448
So there is nothing between the guitar and the amp ? Did they do it before the tube swap ? Feel free to PM or email.


Correct. Before and after new tubes. Both guitars (one with thornbuckers and one with kirn single coils) will do it if plugged straight in with any cable I try.

They'll also do it through the pedalboard unless a pedal is on. But they're totally silent with the THR.

I don't recall it happening at other places which is making me think my house wiring may be causing it if that's possible.

A couple of my pedals make a similar noise as well. This is all equipment under a year old so I can't imagine they'd be dirty or worn out.
 

Husky

Member
Messages
13,455
Correct. Before and after new tubes. Both guitars (one with thornbuckers and one with kirn single coils) will do it if plugged straight in with any cable I try.

They'll also do it through the pedalboard unless a pedal is on. But they're totally silent with the THR.

I don't recall it happening at other places which is making me think my house wiring may be causing it if that's possible.

A couple of my pedals make a similar noise as well. This is all equipment under a year old so I can't imagine they'd be dirty or worn out.
Get a polarity checker from Home Depot and start checking the wall sockets.
 

walterw

Platinum Supporting Member
Messages
41,005
while you're at it get a voltmeter and check DC voltage between hot and ground (tip and sleeve) on a cable plugged into the offending amp.

there shouldn't be any, like @Husky says if there's any DC voltage hitting the volume pot it'll be hideously scratchy when you turn it.
 

rollyfoster

Silver Supporting Member
Messages
18,448
while you're at it get a voltmeter and check DC voltage between hot and ground (tip and sleeve) on a cable plugged into the offending amp.

there shouldn't be any, like @Husky says if there's any DC voltage hitting the volume pot it'll be hideously scratchy when you turn it.

I think the culprit is JJ tubes. I tried 3 of them (new) today in addition to the 2 old ones I had and no difference. It was at a rehearsal space so I could rule out house wiring.

Last ditch effort I put a Mesa in v1 and it was totally fine. There's a super light scratchiness now but it's inaudible unless listening for it. I'd consider it normal. Definitely not the same sound as before and nowhere near as loud. No change when I got back home so all seems to be well at this point. The amp even sounds way more assertive.

It may be random luck but I've had a number of amps in a row that came to me with JJ tubes and had problems with each them. These preamp tubes (and swart ships with JJ), rattling preamp tubes, super rattly 6L6, microphonic 6L6, noisy rectifier tubes, and replacement tubes that had a springy rattle before I even got them out of the box.

Someone will probably tell me Mesa is rebranded JJ...maybe they could be but for whatever reason it cured the ailment when multiple JJs couldn't.
 




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