Signal Slightly Present w/ Volume Down

[batflash]

Hey guys,

Great board! I just can't read enough of the threads here. You guys really keep things friendly, which is really cool.

Of course, I've got an issue. With my freshly wired Les Copy, with GFS buckers, 500k push/pulls, and fairly neat wiring, I'm getting a slight amount of sound coming through with the VOLUME pot all the way down. Any suggestions on what to do?

Thanks for the help,

Jason

PS: This is the second set of pots I've installed with the same issue.

[UnklMickey]

hi Jason,

Welcome to GuitarNuts2!



i realize this might seem to be an unfriendly thing to do to a newbie, but i'm NOT gonna answer your question.

i've been promising myself that i'll leave more room for our next batch of experts to hone their skills.

so i'll leave this one to them for the weekend.

there are 2 very likely causes for this.

when they think about the basic principle of voltage division, i'm sure they'll come up with one or both of the possibilities.

at any rate, i promise an answer Monday or Tuesday of next week.

if you absolutely can't wait, PM ChrisK, or JohnH. they definitely will be able to figure this out.



not that it really matters, but is your guitar a 2 volume model with the pickups connected to the wipers of the pots, or is it a single volume with the pickups connected to the selector switch.



see ya next week,

unk

[batflash]

Well, it's a Two Volume with push/pull coil taps, Two Tone through a 3 way .

Thanks!

Jason

[fobits]

Heh. Unklmickey has been doing a lot of work here lately, answering questions and drawing diagrams in quite a few threads. It's little wonder if he needs a vacation from it.

I can think of two reasons why it could occur, but they might not be the ones he had in mind.

It isn't unusual for a pot to still have a few ohms of resistance even when it's turned all the way down. Manufactures don't worry about it because in most applications it isn't noticeable.

If the signal is fed into a powerful amplifier, it might be.

Another possibility is that the pots have treble bleeder caps between input and output, bypassing the resistance. Some do and some don't.

Those are two possible answers. Anybody else?

[JohnH]

A thought I had was that if a volume pot was missing a ground connection, it would still work to reduce volume, but not go to zero.
If it has two volumes, does the problem happen on both of them?
Are the basic sounds at full volume OK?
Would it be possible to link or post the wiring diagram that is being used?

regards

John

[batflash]

Hey guys,

While doing troubleshooting last night, I figured this so far: The sound only cuts to zero when both volume pots are turned to zero. Otherwise, say I have the bridge PU enabled on the three way, but turned down the volume, and still have the neck PU volume up all the way, I'll still hear sound.

I'm starting to think the 30 year old 3-way switch might be going bad? May this be the result from crosstalk over the 3-way?

BTW, John, everything's grounded. I'll try to draw up a schematic for you. Thanks.

fobits, bleeder caps? Would this be something that I'd have to install or is this a built-in feature of the pot? The only caps I have installed are Metal-Poly Film type 47uf soldered to the mid terminal on both tone pots.

Thanks again. I'll start working on the schemy.


Jason

[fobits]

fobits, bleeder caps? Would this be something that I'd have to install or is this a built-in feature of the pot? The only caps I have installed are Metal-Poly Film type 47uf soldered to the mid terminal on both tone pots.

Like I said, some have 'em and some don't. I believe (could be wrong) that they are most common in the Strat world, where people tend to be fond of high frequencies ;D

Here is a link to an article on the original Guitar Nutz site which explains their location and purpose.


If your guitar doesn't have them, and you aren't complaining about the tone, I wouldn't lose any sleep over it.

When the bridge only is selected, can you tell which pup the sound is coming from? If it's coming from the neck, then suspicion does fall on the selector.

Other than that, I've run out of ideas

[batflash]

I'll have to hit up the GC today to see if I can pick up(<-heh) a 3-way. Though... (here it goes) I don't think my girlfriend's gonna like this.
;D
Anyway, I'll keep you guys up to date on my mini-dilemma.

Thanks for the help, guys,

Jason

[Mini-Strat_Maine]

batflash said:

The only caps I have installed are Metal-Poly Film type 47uf soldered to the mid terminal on both tone pots.

I do hope that's a typo, and you really meant 0.047 microfarad and not 47 µF. I think the latter would make your tone "kinda dark."

There might be a pod of whales somewhere saying things like "That's Jason Batflash! I gotta get his new CD!"

[UnklMickey]

fobits said:

...I can think of two reasons why it could occur, but they might not be the ones he had in mind.

It isn't unusual for a pot to still have a few ohms of resistance even when it's turned all the way down. Manufactures don't worry about it because in most applications it isn't noticeable....

Frank,

that's the first and most likely candidate.

the second one that i thought of, would be some resistance (or in JohnH's example, LOTS of resistance) between the low end of the volume pot and the place where the ground to the output jack and the - of the pickup are connected.

i'm having a bit of a chuckle here, 'cause most people are troubled by having the volume killed by one of the 2 volumes being at zero.

in this case Batflash, you are troubled by the fact that it isn't completely killed.

if you haven't bought that new switch.....don't.

i don't think it will solve the problem.

spend a LOT less money (about $5) on a meter, and check your volume pots and the wiring on the ground side of the pots.

even just a few ohms of resistance, will allow some signal from the other pickup through, when it's volume control is at max.

if the resistance between the wiper and ccw is not zero*, either switch to another brand, or you might even be able to do some surgery, to allow the wiper to get to the end of the track.

high gain settings on your amp will make that more obvious.


(* - check your meter for zero by connecting the 2 probes together. if you read, for instance 0.76 ohms, subtract that value from any measurement you make.)

unk



EDIT: after some additional thought, it could indeed be resistive contacts at the switch that is preventing a pot at zero from completely shorting out the signal.

but i'd still get the meter first.

[batflash]

Thanks Unk,

Unfortunatly I've already bought the switch and installed it. Of course, I've still got the same issue. Also, just to throw it out there, I've got a noise problem, too. Bring both pots to zero and I get a very audible noise. However, when I touch the strings, or anything for that matter(pot shell, internal shielding) the hum is elliminated. This hum only happens when you start turning down the volume. Think it's related(john mentioned it might be a grounding issue).

Gimme some more time on that schematic, btw.

Thanks again guys,

Jason

[batflash]

Here an bit of a clarification, btw.

The sound is NOT coming through if BOTH volumes are down. If one volume is up on say the bridge pickup and I'm switched over to, say the neck pickup with THAT volume down, I can still hear the bridge pickup. I know its the bridge pickup cause i can actually hear sound difference with the coil tap(yes, it's bleeding through THAT loud).

All I can say is... HELP!

Think i should start fresh again and rewire the beast? The only original piece in it now is the 3 conductor+shield connecting the 3-way with the pickups.

-Jay

[UnklMickey]

Jay,

instead of jumping into the rewiring, plan out the new wiring.

and i mean draw it to the last detail.

things like exactly where will the grounds meet.

not just eventually, all along the path.



unk