Tone pot hum?

[jef]

I replaced the pickups in my tele with quarter pounders, while I had it open I also replaced all the crap electronics. After I got done soldering all the new parts in, I plugged in the guitar (without strings or anything) and there is a really nasty hum. It goes away whenever I touch the control plate or the metal around the jack. Any suggestions as to what I might have screwed up?

 

[Artie]

Re: Tone pot hum?

I would check first to see if perhaps you got the two wires that go to the output jack reversed. That would cause the "grounded" metal parts to be hot.

 

[jef]

Re: Tone pot hum?

I forgot the part about the tone pot, whenever I turn it all the way to one side, I'm not sure how to describe which side, but the hum either goes away or I can't here it anymore.

 

[Artie]

Re: Tone pot hum?

Ok, thats a good clue. If you got the cap, or one lug of the tone pot somehow in the wrong place, you might have a condition where one lug of the tone pot was "open", acting as an antenna. When you turned it down to "zero" you'ld ground the "hot" side, which would act as a mute switch. (Killing the hum.)

Look over the tone control wiring, and make sure everything is right. I'll bet, thats where your problem is. A bad cap, would cause the same problem, or one where the value was way too small. For example, if you had a .022pf instead of a .022uf.

Edit: One more thing: when you turn the tone pot down, or up, killing the hum, does it also kill the signal? Or does the pup still work, minus the hum?

Edit2: Is it possible that you've soldered the tone cap to the back of the tone pot, but not grounded the back of the tone pot? That would do it also.

 

[Artie]

Re: Tone pot hum?

Decided not to do a third "edit".

Is the entire control plate grounded? That might also cause that.

 

[jef]

Re: Tone pot hum?

Edit: One more thing: when you turn the tone pot down, or up, killing the hum, does it also kill the signal? Or does the pup still work, minus the hum?

I'm at work right now, but I do know the answer to this question. The rest is going to be the most 'fun' part of a project like this, TROUBLSHOOTING!

Anyway, no it does not kill the signal, it just kills the hum. Thanks for all you help!

 

[jef]

Re: Tone pot hum?

Decided not to do a third "edit".

Is the entire control plate grounded? That might also cause that.

Where do you ground the control plate to? Just solder onto the plate and onto the back of volume pot, or am I totally missing something?

 

[Mephis]

Re: Tone pot hum?

I have the EXACT same problem described here, but when I asked someone, they said "It's just a massive pickup thing."

 

[Artie]

Re: Tone pot hum?

Where do you ground the control plate to? Just solder onto the plate and onto the back of volume pot, or am I totally missing something?

Actually, on a Tele, it's usually not a problem. If you solder to the back of a pot, it should make contact with the control plate through the pot shaft. However, on mine, I fabricated a ground-strap, that goes from under the 3-way, to the ground lug of the pot to avoid soldering to the back of these CTS pots.

I'll see if I can post a pic tonight.

Artie

 

[jef]

Re: Tone pot hum?

I strung it up, just out of curiousity, and these quarter pounders sound totally badass. If I can just get rid of this hum, this is EXACTLY the sound I was looking for.

 

[Artie]

Re: Tone pot hum?

I just took a pair of QP's out of my Tele-clone, only because I'm trying new things out, but yes . . . they are killer.

 

[jef]

Re: Tone pot hum?

I'm guessing that you didn't have the horrible hum all the time, so I know there is something I'm missing, well I'll keep trying to figure it out.

 

[Artie]

Re: Tone pot hum?

Not "horrible" hum, but some hum. I've never been able to absolutely quantify what causes hum and what doesn't. I have some humbucker guitars that hum, and some single-coil guitars that don't. It seems to have more to do with what I have turned on in the room, and which direction I'm facing as anything else.

Fixing hum problems is as much magic as science.

Artie

 

[jef]

Re: Tone pot hum?

Ok here are pics of my tone and volume pots, let me know if you see that I did something incredibly stupid.

Volume Pot

Tone Pot

If there is anything else you want to see, let me know. And thanks again for all your help.

 

[Artie]

Re: Tone pot hum?

I don't see any glaring errors. The solder connection on the back of the pot isn't ideal, but it should be ok. I don't know if I'd reheat it though. I don't like to solder to the back of pots myself, although I know thats the traditional way.

 

[jef]

Re: Tone pot hum?

I know this is a glorified bump, but I'm totally out of ideas here. Any suggestions at all would be a great help. I thought that, possibly, there was a ground issue in my building wiring, but none of my other guitars have the hum.

Artie, you said my grounds aren't the greatest (which, I do realize, I could not seem to get the pot to heat up enough for the solder to flow onto it. If it gets too hot, can they be damaged?) do you think they, potentially, could cause this problem? Also, you said you don't ground to the back of pots, where do you ground to then?

I totally realize I just did something stupid and it is causing me all these problems, but I'll be damned if I can figure it out!

 

[Artie]

Re: Tone pot hum?

I'll try to get a pic tonight showing how I ground. I need to borrow my buddy's Minolta DiMage 7 to get a clear shot. My digital camera sucks.

 

[jef]

Re: Tone pot hum?

Cool, thanks!

 

[jef]

Re: Tone pot hum?

Well, I've been asking around elsewhere and I think part of the problem was me not grounding the bridge plate. I'm guess that is what the extra length of black wire is for in the box.

Is there a specific way to do this? From what I understand you just rap the wire between the screw and the surgical tubing on the screw that is closest to the control plate. Then you ground it to your volume pot. What I'm not clear about is if the bridge pickup should ground to that screw then go to the volume pot or what.

What I don't quite get, as this seems important, is why it isn't shown on the wiring diagrams that come with the pickups. Probably because it is so obvious, hence me totally missing it.