capacitor problem

[JP13]

Hey,
I have 2 pickups, one of them is really bassy. When I put a capacitor (0.0047uF) between the hot wire of the pickup and the switch I can "clean up" the muddiness and cut off some of the low frequencies - perfect! (and btw, in the middle position I like the bass, so there is no capacitor active, only in position 1).

so far, so good, here comes the problem:
when I turn the Tone pot to 0, position 2 and 3 are normal (cut off highs), but position 1 not only has cut off highs, but it also loses volume.

anybody got an idea?

[freefrog]

Hello,

It's due to the hi-pass series cap being before the low-pass regular tone control. The solution is therefore to put the normal tone control first then the series cap, like in the Reverend "Bass and treble control" (they wired it as following precisely to avoid the problem that you describe):

https://tonefiend.com/wp-content/uploads/GL-Tone-Circuit.jpeg

If you have only one master tone pot in a Fender style circuit, alternative solutions are...
-to make the hi-cut and low-cut filters mutually exclusive by mounting them on a Fender TBX pot;
-to use a concentric dual pot giving one tone control per pickup;
-to drill a hole for a second tone control...

Non limitative list.


BTW, a series cap on one pickup only also alters the sound in middle position. It can be heard here:

https://youtu.be/k_NnyvLusj0?t=431

The change is not due to the neck pickup being stronger when the cap is engaged as said in this vid. It's more complex than this (and I'll provide a link on request for further explanations).

FWIW. HTH. :-)

[JP13]

thanks for the answer.

first, the cap only affects position 1, not the middle position (using a 5 way super switch), so the cap is only between pickup and switch connection for position 1.
in the middle position the cap is bypassed, so to say.

if I'd put the cap after the tone pot then every signal, no matter which position would be affected by the high pass cap, which I don't want.
I don't want an additional tone pot and I don't want a dual pot...

And I am not exactly sure how a TBX pot works, but I guess i couldn't use that either, since I send any signal to the tone pot (pos 1 = with cap, pos 2 and 3 without)...

I think there is no solution for my problem...

[freefrog]

Not enough free time to dig it now but is it not possible to use the superswitch to change the location of the tone pot?

Regarding the TBX: it includes a no load 250k pot + a 1M pot... and these two stacked pots can be used independently if needed. IOW, you could associate the 1M part to one of your pickup and the 250k part to the other pickup...
How to place the capacitors would depend on your needs but here is an idea:

Wire the 1M part of the TBX to your neck PU, as a normal tone control, BEFORE the series cap. Pair this 1M part of the TBX with a regular tone cap between right lug and ground: it will behave like a tone control @ 0 for your neck PU as soon as the TBX will be physically @ 5/10 (center/ detent position) and the sound won't change no more from 5 to 0/10 on the TBX for the neck PU (it will "see" the tone cap through the second half of the track, which is a conductive metal ring and no more a carbon track in the 1M part of the TBX).

Now, wire the 250k part as a separate tone pot for the treble pickup : when the TBX will be physically @ 5/10, the tone control will be @ 0 for the neck PU but not engaged for the bridge one. Then, from 4.5 to 0/10, the 250k tone control will be engaged for the bridge unit...

Once the TBX physically set @ 0/10, both pickups will have their respective tone controls at 0. Once the TBX at 10/10, the bridge pickup will have its 250k tone pot disabled (since it's a no load) and the neck PU will have a 1M tone pot full up, contributing to more clarity.

FWIW. If other ideas come to my mind, I'll share my thoughts.

[JP13]

ok, thanks for the reply

sounds like it would be possible, but it's hard to concentrate now. I'll get back tomorrow, but it seems we are onto something.

[JP13]

thanks for your idea, but I want volume and tone pot to work just regularily... but I had an idea, inspired by your TBX pots:

I'll take two stacked 500/500k pots (1 for vol, 1 for tone) and run the neck through the upper parts of the pots (and place the low cut cap after) and the other positions through the lower parts and then put the switch after the whole shebang.
I think this should work, or do I miss something?

[JP13]

this way the however you roll of the pots (5/10 for example), it will affect both pickups, respectively every postition the same way, just like a regular 2 pickup 1 vol 1 tone guitar would do

[freefrog]

It would do what one of the sentences evoked in my first post: "to use a concentric dual pot giving one tone control per pickup".

Now, you could as well use one single dual pot for tones only and put a normal volume control for both after the switch. Should work too and would make easier to use the volume pot IMHO/on the basis of my subjective experience (stacked knobs being less easy to manipulate than normal ones). The choice is up to you. :-)

[JP13]

(stacked knobs being less easy to manipulate than normal ones).

meaning harder to turn?

[JP13]

or harder to solder

[freefrog]

The upper knob can tend to turn with the other one or conversely. Less annoying IME with tone controls...

[freefrog]

And not especially harder to solder to me but requires more precision, of course.

[JP13]

The upper knob can tend to turn with the other one or conversely. Less annoying IME with tone controls...

ah.. yeah... well... that is exactly what I'd want them to do. I would try to glue them together, so there would be 1 knob, dictating the position (the roll-off) for each pickup. you know, just like a regular 1 vol 1 tone guitar.

[JP13]

and thank you, for your suggestions!

[freefrog]

You're welcome. Always glad to help. Let us know how the solution selected works for you. :-)