Wiring question: Can I wire multiple tone knobs with different caps?

[Pblack487]

I have a Seymour-MM custom bass that was active but now has been converted to passive-only. This means I have 3 out of 4 knobs doing nothing on it at this moment.

I wondered if I should wire 3 tone knobs, with 022, 047 and 0.1 caps respectively, in parallel.

Should I do this am I correct to think that I will be able to "blend" the tones of these caps? Surely, if I roll off the 0.1 one too much it will nullify the other ones, but I thought I might roll the 022 far and use the others to control any mids that peak beyond my liking.

If anyone knowledgeable on the matter can shine some light on this for me I would appreaciate very much!

 

[Jefenator]

My stack knob J bass has 2 tone controls, a .047 and .1. (It used to have resistors to help isolate each control to one pickup but I snipped those out so now both tone circuits are "global".)
I usually just use the .047 but the other day I felt a hankering for a little extra "dub" and the .1 worked nicely. I think they're supposed to "sum" in theory when you use both, but I've found the difference is pretty subtle over just using the .1 - and that's already a little overkill.
It's not something I would go out of my way to set up. OTOH I really like the way the bass sounds as-is so I'm in no hurry to change it to 3-knob.
If I had a passive MM with 4 knobs I'd be tempted to try one passive tone circuit and a 2-band boost only active EQ. Best of both worlds. My Roscoe has that and it's great. (I like 2-band and I really like a good passive tone but for some reason I've never cared for the active mid knob.)

 

[bholder]

Sure. You may or may not like the results. It works, but having two bleed-off resistors in parallel yields half the total resistance, which affects tone and everything. I've tried it a few times on guitars using .22 caps for the treble and a Bill Lawrence Q-Filter inductor for the mids. Seems to work.

 

[Pblack487]

Sure. You may or may not like the results. It works, but having two bleed-off resistors in parallel yields half the total resistance, which affects tone and everything. I've tried it a few times on guitars using .22 caps for the treble and a Bill Lawrence Q-Filter inductor for the mids. Seems to work.

Would wiring them in series grant the usability I look for? The capacitance would be summed at each stage so the effect would be increasingly dramatic as I engage each one after the other (total cap at 0.169 with all three)

 

[bholder]

Would wiring them in series grant the usability I look for? The capacitance would be summed at each stage so the effect would be increasingly dramatic as I engage each one after the other (total cap at 0.169 with all three)

I don't think that will do at all what you want. You're just further "squeezing the drain" with that approach. you want them in parallel to cover different frequency ranges, no?

 

[Pblack487]

I don't think that will do at all what you want. You're just further "squeezing the drain" with that approach. you want them in parallel to cover different frequency ranges, no?

Indeed, pardon my ignorance.

So my first thought was more accurate. But you mentioned that in parallel, the resistance would be halved, affecting tone. Regarding that I have a question:

When does it affect tone? Only when engaging the tone control or does it affect tone even when the tone knobs are at 100% 'open' position?

I am trying to wrap my head around it here... Using 3 pots of 500k each, that would mean my total resistance would be 500/3 or around 166k. This is very low, and means that tone will be overall 'darker' than if I had a single 500k pot with an equivalent cap attached to it?

 

[bholder]

My electronics understanding is decades old and forgotten, so yeah, I'm wondering too, hoping someone more expert than I chimes in.

 

[kgbeast]

Indeed, pardon my ignorance.

So my first thought was more accurate. But you mentioned that in parallel, the resistance would be halved, affecting tone. Regarding that I have a question:

When does it affect tone? Only when engaging the tone control or does it affect tone even when the tone knobs are at 100% 'open' position?

I am trying to wrap my head around it here... Using 3 pots of 500k each, that would mean my total resistance would be 500/3 or around 166k. This is very low, and means that tone will be overall 'darker' than if I had a single 500k pot with an equivalent cap attached to it?

Tone knobs are not connected directly to the ground, so I do not think this will result in anything audible when the tone is all the way up. The 3 tones will add up when in use. So you will have a sum of 3 capacitors which will remove most of the signal, but there are some interesting combinations between the 3.

 

[BlueTalon]

I have a Seymour-MM custom bass that was active but now has been converted to passive-only. This means I have 3 out of 4 knobs doing nothing on it at this moment.

I wondered if I should wire 3 tone knobs, with 022, 047 and 0.1 caps respectively, in parallel.

Should I do this am I correct to think that I will be able to "blend" the tones of these caps? Surely, if I roll off the 0.1 one too much it will nullify the other ones, but I thought I might roll the 022 far and use the others to control any mids that peak beyond my liking.

If anyone knowledgeable on the matter can shine some light on this for me I would appreaciate very much!

I think something like that could work, assuming the separate tone controls are all no-load. In other words, when they are at maximum through-put, they take themselves out of the circuit. Then, you could use one at a time, or mix-&-match and experiment as you feel the urge.

 

[joeLowB]

Man, this reads like a story problem from my Electrical Engineering undergrad AC circuit classes. You have two low pass filters operating in parallel. Capacitors in parallel add...resistance halves. With variable resistors (aka "pots) yet fixed capacitors, even the theory gets confusing. And would it help?

Would not a better use of the empty slot be to simply switch in or out the capacitors, leaving the (presumably) 250K pot intact? That would slide the rolloff frequency at varying slopes without confounding the resistances.

All of that is also to say...is it worth it?

Which brings to mind one of my EE profs pointing out that just because you CAN draw up a certain circuit, the job of the engineer is to make sure it is actually WORTH doing it.

Go Purdue .


.

 

[kgbeast]

... WORTH doing it.

.

... Is definitely misplaced here. Majority of TB users are constantly involved in things that are not worth doing. When it comes to hobby and passion, it is always worth it. Because if you do not, you will just continuously wonder "... what if?". So yes, OP, knock yourself out. And if you do not like it, you can wire it back the way it was. But before that, comeback here and write your assessments on the subject.

 

[40Hz]

Hmm…maybe try:

2 volumes
1 tone
1 capacitor switcher or Wilde/Lawrence QFilter

or

1 volume
1 blend
1 tone
and either a Wilde/Lawrence QFilter or a capacitor switcher

 

[sikamikanico]

Yeah, unless you use no load pots, each additional tone control will darken the sound.

But I don’t think it will be useful either way. But I could be wrong, it’s just intuition based on incomplete understanding of electronics. Maybe @micguy could explain what would happen, maybe even do a spice model to show it visually?

I would recommend using a capacitor selector switch like Tonestyler. You can also make your own for cheap. You can wire it to change the caps on the tone control, or to function independently from the tone control (I’d use the latter).

4 holes, I’d consider a coil selector switch (neck/both/bridge), volume, tone, capacitor switch.

or install a producer switch

 

[andruca]

I'd do 10nF, 22nF and 33nF, in parallel. You'd have many usable combinations.

Another (better IMHO) option would be to use one hole for a rotary selector for different cap values, one for tone pot itself, and the other for a series/parallel switch or anything else you could switch in your bass (any photos?). I've done particularly the cap selector switch thing in my StarBass 5, converted it from VVTT to VVT + 5 position cap selector (10, 20, 32, 43 or 57nF). Works amazing, but I mostly use it either in 10 or 20nF (most passive basses I own have 22nF tone caps).

 

[Pblack487]

Considering everyone's takes here, I decided to go the route of this post here:

https://www.talkbass.com/threads/multi-capacitor-tone-control.737912/#post10398124

In addition to the 3 duds I currently have, the bass also has 2 swtiches. One 3 way and a 2 way, that were usd for passive/active/off settings and a mid selector for the active preamp.

So I am gonna use the 3 way switch as a cap selector, the 2 way as an on/off, one of the dud pots as the tone and the remaining two I am just going to ignore for now. This will give me kind of what I want with minimal additional investment

 

[31HZ]

Man, this reads like a story problem from my Electrical Engineering undergrad AC circuit classes. You have two low pass filters operating in parallel. Capacitors in parallel add...resistance halves. With variable resistors (aka "pots) yet fixed capacitors, even the theory gets confusing. And would it help?

Would not a better use of the empty slot be to simply switch in or out the capacitors, leaving the (presumably) 250K pot intact? That would slide the rolloff frequency at varying slopes without confounding the resistances.

All of that is also to say...is it worth it?

Which brings to mind one of my EE profs pointing out that just because you CAN draw up a certain circuit, the job of the engineer is to make sure it is actually WORTH doing it.

Go Purdue .


.

EE dropout here, with the same conclusion: use a switch so that only one is in the circuit at any given time.

 

[crazyBassClown]

Would wiring them in series grant the usability I look for?

Capacitors in parallel increase the total capacitance, capacitors in series decrease it, the opposite of resistors. So no I don't think it will do anything useful for you

I think the switch idea to select between a few cap values is probably the best but I have never actually done it, I tend to leave my tone full up all the time.

 

[ceetee]

EE dropout here, with the same conclusion: use a switch so that only one is in the circuit at any given time.

No load pots or push/pull should behave equally when in serial. Guess p/p are easier to find and you could apply your desired tone immediately without sweeping.

I'd like to try with something like a TH Custom Effects madbox splitter/mixer. Tone controls in between. A 3-way switch (sw1) before the splitter to chose tc1, tc2 or splitter. P/P pots for tc1 and tc2 let you add them to the chosen single tc option from sw1. Output goes to EQ boost.

I guess I need to get a tinkering bass and carve out some space only to find out that I prefer what is my goto now. Seems to be the motto of my adventures in tinkering.

 

[mjmeche]

I used a stellar tone tonestyler

 

[BlueTalon]

I have a Seymour-MM custom bass that was active but now has been converted to passive-only. This means I have 3 out of 4 knobs doing nothing on it at this moment.

I wondered if I should wire 3 tone knobs, with 022, 047 and 0.1 caps respectively, in parallel.

Should I do this am I correct to think that I will be able to "blend" the tones of these caps? Surely, if I roll off the 0.1 one too much it will nullify the other ones, but I thought I might roll the 022 far and use the others to control any mids that peak beyond my liking.

If anyone knowledgeable on the matter can shine some light on this for me I would appreaciate very much!

Let me show you what I did.

There are four stacked controls; a V/T for each pickup, and a master V/T. (The oddball is a 6-position rotary selector switch, of which five positions are voices and one is full manual control of the pickups.) So there are four capacitors involved. I don't remember what size, but they're small. Each of the tone pots are no-load. When I had this idea in my head, everyone but one said it wouldn't work, or that it was a dumb idea, or something like that. One guy said he thought he could make it work. Well, it works, and it works brilliantly. Would I do it again? Probably not, but I'm glad I did it the one time.

If you have an idea in your head and it just won't leave you alone, give it a shot. The worst that can happen is it won't work as well as you think. And then you still have a bass with all the necessary parts to make it work in a more conventional manner.