Tone knob noise

[paleolith54]

Searched related threads, read about grounding, hands on strings, QC issues with pots, etc. Unless I missed something my problem is different.

Everyone knows what a volume swell is: imagine you were doing a "tone swell"; hit a chord, keep fingers in place, let it ring, adjust tone knob. When I do that it's very scratchy. My memory is that it's been this way since I bought the guitar, just never mattered until I (finally!) got a band going and started playing louder.

A variable I just noticed yesterday: when I wrap my pinky around the knob, the minute amount of pressure seems to create some crackling before I even turn the knob.

Simple pot problem? Bad solder joint? Something more subtle? Suggestions appreciated.

[mdrs]

Sounds like a pot issue.

[bsmith]

It almost sounds like a grounding issue. Especially if it has done it since day one. Is the guitar rear routed? Pickguard? Tone on a Push Pull? Sometimes pickguards and sheilding can build up a static charge. Of course without seeing the guitar or hearing the problem, it's all speculation on what the problem could be. Hopefully Tom will chime in.

[tom]

i've said it e;sewhere here but who knows where. the modern pots have a non conductive lube on the shafts to make them feel smooth. it can create an intermittent connection between the pot shaft and bushing(which is the part connected to internal ground of the guitar). with a metal knob, if you are not touching any other ground on the guitar, stiungs, bridge, it can make a scratchy sound like if you were to let go of the guitar and quickly touch and un touch the strings. it should not be happening if you are touching the strings. do a quick test. touch the bridge and then with the other hand turn the pot. if there is still noise the pot has gone bad. i spin every one here when i play test the guitars, but pots can go bad.

[paleolith54]

Thanks guys, I figured a bad pot but thought I'd cast about for a simpler solution in case I was missing something. Tom, I'll get with Rachel and order a pot.

[lvergne]

Before you switch the pot, did you check to see if any other knobs are scratching too? If so, you may want to check any other guitars as well. If they are scratching too, then it is obviously not the guitar. It will be your preamp tubes.

[tom]

you could also try spraying the pot first.

[paleolith54]

Tom, since you're taking the time to respond here, two follow-up questions.

1. There seem to be different opinions regarding what to spray with: what do you guys recommend?

2. What am I looking for on the pot itself as the target of the spray: an opening? Haven't done this before.

[tom]

deoxit D5 is the best. it's usually available from fry's or any decent elec store. radio shack won't have it but their contact cleaner isn't bad.
if you remove the cover plate, you'll see an opening above all the terminals on the pot. spray into there, one good blast will do. the stuff will go all over the place but it will dry and not hurt anything. spin the pot a few times and it should be good to go.
if that doesn't work, email me and i'll send a replacement.

[paleolith54]

Thanks all, I'll give it a go this weekend.

[paleolith54]

The Deoxit fixed it, thanks Tom.

[tom]

it's magic stuff.

[mdrs]

Don't you love it when a plan comes together?? :)