2 master volumes, 250K and 500K, problems

[mortlake]

Hi there,

My first post, after acting on good advice from original GuitarNuts site.

I have a Tele with P90 in neck position, both pots acting as volume controls, bridge pickup has 250K pot as normal, and the P90 has 500k pot (as specified by the maker).

I have the problem where both pickups mixed gives me a thin sound with both pots on full, and the sound improves when you back them off 10%. So using advice from the GuitarNuts site, I tried adding in a couple of 30k resistors (not much difference), and then upped them to 60k (slightly better).

But I still find that if I dial in even a small amount of P90, that removes low end from the bridge pickup.

Is this problem made worse by the different pot values?
Can anyone suggest any other ideas?

Thanks in advance,
David S.

[UnklMickey]

hi David,

welcome to GuitarNuts2.

i would expect when the 2 pickups are used together, you would describe the sound as "smoother" but not "thinner".

unless of course, they are out of phase with each other.

try changing the phase (exchanging the connections) of ONE of the pickups.


good luck,

unk

[mortlake]

Thanks Unk,

I'll try that.

Its funny though, the 'Stock Gibson wiring page' of the GuitarNuts site seems to explain the problem of 2 master volume pots loading each other when both maxed, and causing thinning of the sound, and it looked a direct match for my problem. The pick-up wire colours indicate the phase is fine too. Still the P90 is 'home-made' - not by me, so it could be back-to-front.

Thanks for the quick reply, I'll update when I've tried it.

Best,

David S.

[gumbo]

Yep, same *&%# thing outta my recently-acquired MIJ 72 Custom RI.....it's not a #1 priority for me just now as other things are happening, but I'll still be VERY interested to see where all this goes... This one is going to get significantly ripped to bits and fitted with a Bigsby Palm Pedal, when I can afford to take it 'off the road' for a while...meantime it's gotta just keep going while the Strat gets ripped to bits for 13-pin stuff......:-)

Why DO we do this stuff??

[ChrisK]

Its funny though, the 'Stock Gibson wiring page' of the GuitarNuts site seems to explain the problem of 2 master volume pots loading each other when both maxed

The "Stock Gib$on" wiring will cause attenuation of both pickups when either volume pot is minimized (turned nearly off) and both pickups are selected.

I have the problem where both pickups mixed gives me a thin sound with both pots on full, and the sound improves when you back them off 10%

If "full" means full on, then you do appear to have a phase issue. If "full" means full off, then you appear to have a Stock Gib$on wiring issue.

But I still find that if I dial in even a small amount of P90, that removes low end from the bridge pickup.

Sure sounds like a phasing issue.

I have a Tele with P90 in neck position, both pots acting as volume controls, bridge pickup has 250K pot as normal, and the P90 has 500k pot (as specified by the maker).

Note that this volume pot selection is "proper" when either pickup is selected alone, but the combination of both pickups results in a paralleled pot load resistance of 167K Ohms. This will make the combo darker sounding.

[mortlake]

Thanks for the responses.

I tried reversing connections on one of the pickups (swapped the earth with the hot connections to the 250k pot controlling the bridge pickup) - but the result was a loud hum/buzzing un-earthed sound from this pickup, which got louder when I touched the strings.

So I guess either I don't know how to change the phase or something else is happening. Probably the first one!

Is it something to change at the switching end?

ChrisK or Unk, please could you advise me?

Thanks,
David S.

[UnklMickey]

hi David,

what you described, sounds to me like the "-" wire for the bridge pickup is also making the connection for the string ground.


is it possible to change the phase on the neck pickup instead? or does that have a shielded cable?

[ChrisK]

Do you have a wiring diagram/schematic?

[mortlake]

Hi Unk,

You're right - there are only two wires out of the (tele) bridge pickup cavity, therefore the earth must be connected to the bridge/strings as well as the pickup.

The other pickup (P90) has a shielded cable with 2 cores (red and black). Currently the red is hot and the black is joined with the shield and connected to earth.

Therefore to change the phase I'll have to strip it back a bit, and change the shield so that it joins to the red instead, and then make the black hot and the red+shield earth, right?

Thanks for your patience with this!

Hi ChrisK - the schematic I'm using is the GuitarNuts 'Typical Gibson wiring' except without the tone pots. It looked simple when I started....

Cheers
David S.

[UnklMickey]

mortlake said:

...Therefore to change the phase I'll have to strip it back a bit, and change the shield so that it joins to the red instead, and then make the black hot and the red+shield earth, right? ...

sounds right to me!

[mortlake]

Bingo! Now it works fine, so it was a phasing issue.

Thanks so much for the advice Unk and ChrisK, I owe you beers!
As do many.

Now I've got it sounding as planned, I could start to miss the weird out of phase mixing behaviour, like an upsidedown tone control (ok, I know that's called a high-pass filter).

... maybe time to change to a 5-way tele switch and make it an option!

Cheers,
David.

[UnklMickey]

hi David,

we're glad to hear things worked out for you.

mortlake said:

...I could start to miss the weird out of phase mixing behaviour...

if you exchange one of your volume or tone pots, for one that has a push-pull switch on it, you wouldn't have to change the pickup switch.

cheers,

unk

[ChrisK]

if you exchange one of your volume or tone pots, for one that has a push-pull switch on it, you wouldn't have to change the pickup switch.

True, but Parallel Out Of Phase is anemic at best (worst).

Now, a scheme that uses one push pull pot for the neck volume and to reverse the phasing, and another for bridge volume that switches the neck into series with the bridge.......

[UnklMickey]

chrisk said:

...True, but Parallel Out Of Phase is anemic at best (worst)...

...True, but Parallel Out Of Phase is anemic at best (worst)...




c'mon Chris, don't sugar-coat it. tell us how you really feel about it! .:lol:.

[mortlake]

Yes, I've never heard this pickups-in-series sound that people talk about, its supposed to be louder at least...I guess Chris is saying that series out of phase (that would be SOOP) is better?

So anyway I quite like the sound of the 2 push-pull pot idea. To be continued.

For the moment though, I need to get back to actually playing the thing!

[JohnH]

Yes - better play it for a while.

But when you get intrigued enough to take the next step in wiring (say by about 9.30 tomorrow evening), what you have described could be the basis of one red-hot Tele.

I'd keep your independent volumes, but with each having a push/pull, one can do phasing and the other series/parallel. As you saw with your earlier wiring, changing the volumes relatively makes an Out-of-phase (OoP)wiring spin through a very large range. Having one pup diminished and one on full means they do not cancel out so much. Putting them in series sounds better for OoP.

Series in-phase is great for powerful overdrive, and more humbucker style sound. Again the mixing is interesting, e.g, take a bright bridge pup, and add just a touch of extra bass from the neck. Or set a neck rhythm sound, and put that in series with full bridge for a lead solo.

I have been playing with series/paralell wiring with independent volumes on humbucker and Strat circuits recently, and I reckon this could work very well.

John

[mortlake]

Hi John,

Thanks for that... I think you've got me curious enough to take the next step!

At least to check out some wiring diagrams and find out if push-pull pots will fit in my tele control cavity without any carpentry...

Cheers,
David.