SPDT On-Off-On to switch between tone caps?

[Javi_C]

Hello,

I have a bass with volume, volume and tone controls and an extra hole in the body from a previous old pot that is not in use anymore. I put in a SPDT On-Off-On toggle switch in that body hole and wired the switch center lug to lug 3 of the tone pot and the switch left lug with one leg of a .047 uF cap and the other cap leg to the pot's ground or case. The right lug of the SPDT switch I wired it to one leg of a .022uF cap and the other leg to the tone pot ground.

I was expecting to be able to switch between the two caps values. But what happens is, that I only get tone control with the 0.047uF cap that is connected to the switch left lug, which is when the switch is on the down position. When I throw the switch up or in the straight position, the tone pot does not work, meaning it won't get dark even with the tone knob rolled down to 1 or 0.

I tried changing between the switch left and right lug, but what it seems is that whatever I wire to the switch right lug doesn't work. I mean I will get sound, but it won't have tone control. Only if you wire the tone cap to the switch left lug, will I get tone control.

At the moment I have nothing connected to the right lug of the switch and I am getting the same results as when I had the 0.022uF cap soldered to the right lug.

So basically what I am getting right now, is being able to switch between tone control with a capacitor, the switch in the down position and no cap or tone control, the switch in the straight position.

I have attached a picture of the diagram that I followed.

Am I probably missing something here, or could there be a chance of a faulty switch? This looks like a quality switch, it is a Japanese made $14 switch. I think there could be very small chances to get a bad switch.

Thanks a lot!

 

[MynameisMe]

You might have a faulty cap also. If you have an extra you could install it where you had the .022 cap and see.
I have recently began experimenting with cap values.
Very interesting!

 

[Javi_C]

You might have a faulty cap also. If you have an extra you could install it where you had the .022 cap and see.
I have recently began experimenting with cap values.
Very interesting!

I think it may not be a faulty cap, since I tried the working cap in that position and it did not work.

Yeah I think is cool to try different caps. So far I have tried 0.022, 0.028 and 0.048 uF

 

[Javi_C]

But also I guess it is kind off cool to switch between cap and no tone control...

 

[MynameisMe]

I tried the .022 on my Jazz bass and it sounded horrible. I bought two of the .047 and installed new ones on my Jazz bass and my #1 P bass. Sounds marvelous!
You can really tell on the Jazz though.

 

[Javi_C]

I tried the .022 on my Jazz bass and it sounded horrible. I bought two of the .047 and installed new ones on my Jazz bass and my #1 P bass. Sounds marvelous!
You can really tell on the Jazz though.

Yeah I did not like the 0.022uF either. But I really like the 0.047uF!

 

[Javi_C]

I always wanted to try to be able to switch between a tone control with a capacitor value and one without it, like "wide open", but I never thought of how to do it. This came by accident. I guess there does not seem to be any difference when I put the tone knob in 10 than when I switch it to the no tone pot bypassed position. So it does not seem to give me any sonic advantage to have the tone pot on 10 or bypassed.

But I have read about some people saying they have the tone pot bypassed and they like it better like that. Some guitar players say some pickups like the middle pickup of a Strat guitar sound better with the tone control bypassed or not connected, but I don't know if this could relate to a bass or even if my circumstance applies.

I guess I could leave it as it is. For example, I can be playing with the tone knob rolled of like at 5 and get a nice darker sound and then with the instant flip of a switch, I can be back in bright territory. So I am not sure if what I have now might be interesting and useful, but I guess I can try it for a few days and see how it goes...

 

[ex-tension]

...I tried changing between the switch left and right lug, but what it seems is that whatever I wire to the switch right lug doesn't work. I mean I will get sound, but it won't have tone control. Only if you wire the tone cap to the switch left lug, will I get tone control.
...could there be a chance of a faulty switch? This looks like a quality switch, it is a Japanese made $14 switch. I think there could be very small chances to get a bad switch.

Sounds like faulty switch. Too much heat during soldering might damage it. Measure it if you have a multimeter (or with a LED, resistor and battery).

 

[dwizum]

I would agree with comments above that it sounds like a bad component or a wiring fault.

When switching between tone pot cap values, it can be better to hard wire a single cap, and then use a switch to add a second cap in parallel. That will eliminate the tiny "pop" you'll get throwing the switch otherwise. Of course if you want a "disconnected tone pot" option (your center off) you will get the pop anyways, unless you're creative with some very high value bypass resistors.

 

[themickster]

I would agree with comments above that it sounds like a bad component or a wiring fault.

When switching between tone pot cap values, it can be better to hard wire a single cap, and then use a switch to add a second cap in parallel. That will eliminate the tiny "pop" you'll get throwing the switch otherwise. Of course if you want a "disconnected tone pot" option (your center off) you will get the pop anyways, unless you're creative with some very high value bypass resistors.

Would it work to have a cap wired to the pot and another to each of the switch poles to give a 3-way tone control? That's if the switch is OK.

 

[fermata]

One thing to consider when switching tone caps is that there’s no difference between them until you turn the tone control (almost) all the way down. That’s because parallel resistance dumps the highs to ground. The cap is there to prevent the whole signal from going to ground near the end of the pot’s travel. But when the tone is turned down all the way, that extra capacitance retunes the circuit, giving a mid-bump, and that’s where different cap values sound quite distinctive.

After playing with different tone caps quite a bit, I found that very small value caps, used as loading caps to change the circuit’s resonance, can be really interesting, almost like switching pickups. One or two caps can be put on a switch between the pickup’s hot lead and ground before the volume pot. Values from .001 to .005 uF are interesting for this application.

Anyway, just another thought if you’re trying to repurpose an empty hole.

 

[OldSchoolFlats]

Wow, that should work. Years ago, I had a 5-way rotary switch, with 5 different cap values.

 

[dwizum]

After playing with different tone caps quite a bit, I found that very small value caps, used as loading caps to change the circuit’s resonance, can be really interesting, almost like switching pickups. One or two caps can be put on a switch between the pickup’s hot lead and ground before the volume pot. Values from .001 to .005 uF are interesting for this application.

Many popular active onboard preamps take advantage of that approach by putting a small cap on the input to the preamp. That's a big part of what gives certain preamps their distinctive voices.

 

[JeezyMcNuggles]

Wow, that should work. Years ago, I had a 5-way rotary switch, with 5 different cap values.

Get an on on on switch instead. Same caps. Ground to center lugs, cap on top left, cap on bottom right. On/on/both on

That might be pretty cool.

Or, standard 47 on top, grease bucket in bottom. That'd also be pretty cool. With the grease bucket though, you want a higher value. Otherwise it still let's a good amount of high end through with it all the way off. I had good luck with a 65. Still doesn't up the low mids, but takes off about as much treble as a standard 47.

 

[JKos]

If your switch is on-off-on then it has three positions. Are flipping it all the way to the "no working" side?

 

[andare]

I always wanted to try to be able to switch between a tone control with a capacitor value and one without it, like "wide open", but I never thought of how to do it. This came by accident. I guess there does not seem to be any difference when I put the tone knob in 10 than when I switch it to the no tone pot bypassed position. So it does not seem to give me any sonic advantage to have the tone pot on 10 or bypassed.

But I have read about some people saying they have the tone pot bypassed and they like it better like that. Some guitar players say some pickups like the middle pickup of a Strat guitar sound better with the tone control bypassed or not connected, but I don't know if this could relate to a bass or even if my circumstance applies.

I guess I could leave it as it is. For example, I can be playing with the tone knob rolled of like at 5 and get a nice darker sound and then with the instant flip of a switch, I can be back in bright territory. So I am not sure if what I have now might be interesting and useful, but I guess I can try it for a few days and see how it goes...

When the tone pot is all the way up the capacitor has no effect on the signal but the pot still applies resistance and therefore cuts some high end. Some people like to disconnect the middle pickup on a Strat from the tone pots because it becomes brighter, making 2nd and 4th position brighter too. These players usually won't use the middle pickup by itself. The Eric Johnson signature Strat is wired that way.

I agree that your switch is faulty and it's easy to verify that with a multimeter. BTW $14 for a switch is a daylight robbery no matter the quality.

You got good suggestions in this thread. Something else you could do is have 3 sounds, from brighter to darker: 1) pickup w/tone pot bypassed, 2) pickup w/tone pot w/no cap and 3) pickup w/tone pot w/cap

It's too early in the morning for me to figure out how to wire that but guitar electronics are very simple.

I second the suggestion to add caps in parallel. I did that to a Foxx Tone machine clone to add back some mids, though I used a DPDT on-off-on switch in that pedal.

 

[JKos]

@andare ,
The tone pot is in series with the tone cap. When there is no tone cap, there is no load from the tone pot.

If the OP's on-off-on switch is working correctly and based on how he wired it, it should be tone cap A, no load, tone cap B.

 

[andare]

@andare ,
The tone pot is in series with the tone cap. When there is no tone cap, there is no load from the tone pot.

If the OP's on-off-on switch is working correctly and based on how he wired it, it should be tone cap A, no load, tone cap B.

I thought a pot always loaded the signal regardless of the presence of a cap. The volume pot loads the signal too, doesn't it?

 

[JKos]

I thought a pot always loaded the signal regardless of the presence of a cap.

Not the tone pot. The tone pot acts as a variable resistor in series with the tone capacitor. Remove either and there is no longer a circuit to cause a load.

The volume pot loads the signal too, doesn't it?

Yes, volume pots are always a load. But it is connected differently than a tone pot.

 

[fermata]

The circuit doesn't 'see' the cap until the pot is near the end of its rotation. As demonstrated here, it could just as well be a piece of wire - and sound the same.



Alternatively, one can also wire up a capacitor without a pot, and it will sound the same as a tone pot turned to 0.