How to make a tone switch

[DeusM]

Hey guys. I Got an idea building my BMP but I'm not sure how to make. I know it should be easy but it's always to ask experts first. So, the concept is to create a tone switch so when I press it, the tone is almost at 10, maybe 9 (being 0 nothing and 10 the maximum). I guess I should combine a resistance and a footswich. I want it to be activated after the switch is pressed, not a momentary switch (sorry is my English is too bad). So I guess I should look at the value the pot is at the point I want the effect to be at and then, well, know how to make the connections.
Also, how can I add an LED so I know it's on? Will it be easier with a 3dpdt?
I leave a diagram of the tone stage in the schematic.

Thanks!

[Plexi]

If I'm correct, you should link lug 2 with 3, or lug 2 with 1.
Maybe dpdt switch for link and led activation is ok.

You wan 2 position: full open tone, and full closed tone?

[Cozybuilder]

I think you are describing removing the Tone pot and replacing it with 2 resistors and a switch to obtain 2 tones, rather than have the variability of a pot.

If that is correct, select 2 resistors (RA and RB) that together total the value of the tone pot. For instance, if the pot is 100K, you might select 47K and 47K, or 33K and 68K).

Wire like this:

[DeusM]

I still want to have the pot control but have a switch for a fix tone also to add a "special tone" for some of the songs I play. So when I activate the switch it goes to  specific tone and when I deactivate it goes to the tone set by the pot position.
Thanks plexi and cozy for the drawing. You are awesome! But I'm having trouble trying to understand it, sorry, I'm too noob 

[DeusM]

Actually, the problem comes from understanding how the pot works too. My guess Is that when its fully open the signal goes to 3 and when its fully closed the signal goes to 1. Is that correct? I understand the drawing a little better now 

[Cozybuilder]

Deus-
If you just want to flip to high treble for one tone setting, and have the normal variable tone, then just wire in the switch as drawn, RA and RB are the pot, the wiper is the connection point between the resistors.

[Mark Hammer]

The original Little Big Muff did this very thing.

Essentially, a switch was used to duplicate the action of rotating the normal tone control between the 7:00 and 5:00 positions, with nothing in between.

It used the stock BMP tonestack components, but there is no reason why you have to.  For instance, that .01uf cap to ground could be to raise the rolloff from 408hz to 868hz.  That sounds still low, but since it is only 6db/oct rolloff, there will still be plenty of definition.  Likewise, that .004uf cap could be raised to .0047 or even .0056 for a low-end rolloff of 1540hz or 1290hz, respectively.  So, thin-sounding but still lotsa meat and guts.

And so on.

[DeusM]

Deus-
If you just want to flip to high treble for one tone setting, and have the normal variable tone, then just wire in the switch as drawn, RA and RB are the pot, the wiper is the connection point between the resistors.

And don't just to roll it all the ways. I said between 10 and 9. And also I need a LED. The diagram is great for starting but if someone can give me a hint about how the tone sention works mayby I can figure it out.

[Cozybuilder]

Another approach is to wire in a parallel pair of pots where the tone pot is, each should be double the resistance. Example if the tone pot is 100K, then wire in a pair of 200K pots in parallel, so the overall resistance is as original. One of these could be a trim pot- take the output off the wiper of that & adjust until it has the tone you want for your "Preset" on the selector. The other will be the full size pot with the knob on the face. Your other selection "Normal" is taken from the wiper of that pot. Wire the selector (DPDT) so that the outer poles go to the wipers, the center pole goes to the cap out.



edit: clearer photo of schematic

[DeusM]

Ohh I'm kinda dizzy now. What if I just recreate that section, one with the pot and the other with the desired resistance for the tone? And then, bypass it with the switch. That way it will be easier and dont have to go throu that much trouble.

[GiovannyS10]

Hey DeusM, i had a question like this a time. I just used a ON-OFF-ON SPDT toggle switch and added two trimmers, one in each toggle edge. So i could regulate the correct resistance in each trimmer, you see? It seems a little like the Cozybuilder's schematic. When it was up we got a low tone, mid we got a bypass, and down we got a treble tone... Maybe it can solve your question easy... Maybe... Let me know if you need a schematic... I will be glad in do it for you 

Hope help

[DeusM]

Hey DeusM, i had a question like this a time. I just used a ON-OFF-ON SPDT toggle switch and added two trimmers, one in each toggle edge. So i could regulate the correct resistance in each trimmer, you see? It seems a little like the Cozybuilder's schematic. When it was up we got a low tone, mid we got a bypass, and down we got a treble tone... Maybe it can solve your question easy... Maybe... Let me know if you need a schematic... I will be glad in do it for you 

Hope help

I thoug of that but I need a footshitch so I can change the tone while I'm playing. My main question Is where shloud the Led and its resistor go so it doesn't affect the rest of the circuit.
I think I want it with the full open tone so what about this schematic?

[anotherjim]

Panel pot change to 220k. A 220k trimpot is wired across it in parallel. A SPDT switch changes the output over between  either pots wiper. The total value of pot the tone control sees is 110k, close enough to 100k to not matter. The trim pot is your switched preset. Use a DPDT switch if you want to add an indicator LED.

[DeusM]

Panel pot change to 220k. A 220k trimpot is wired across it in parallel. A SPDT switch changes the output over between  either pots wiper. The total value of pot the tone control sees is 110k, close enough to 100k to not matter. The trim pot is your switched preset. Use a DPDT switch if you want to add an indicator LED.

Not sure how to do that 

[Cozybuilder]

Panel pot change to 220k. A 220k trimpot is wired across it in parallel. A SPDT switch changes the output over between  either pots wiper. The total value of pot the tone control sees is 110k, close enough to 100k to not matter. The trim pot is your switched preset. Use a DPDT switch if you want to add an indicator LED.

Not sure how to do that 

See reply #8 for a schematic of this

[Quackzed]

You could do this, it will switch between the tone pot and your 9 setting with a led, you choose the new resistor above the tone pot for how much treble, maybee 10k or 22k...  but it will make your  '9' setting the highest setting = your tone pot will only go to '9'. you choose the new resistor above the tone pot for how much treble, maybee 10k or 22k...  but might be easier to understand how to build.

[DeusM]

You could do this, it will switch between the tone pot and your 9 setting with a led, you choose the new resistor above the tone pot for how much treble, maybee 10k or 22k...  but it will make your  '9' setting the highest setting = your tone pot will only go to '9'. you choose the new resistor above the tone pot for how much treble, maybee 10k or 22k...  but might be easier to understand how to build.

Wouldn't that extra resistor change the tone? If not, when I activate the switch, the tone will be diferent from the pot position fully open?
What if that extra resistor is omited (the one next to the 3)? Wouldn't it work the same but until 10?
Also, is there a way to make the volume drop a litle? Mayby ading a resistor that goes to pin 1 of the volume pot?

[DeusM]

BIG UPDATE: So, i figured out that R19 actualy went to positive!!! Yes, but it has a killer sound! So, it shloud be easier to make a diagram now since I can have 2 resistors, One the 19 that goes to negative, and another that goes to positive from the switch, but I still dont know where to put the LED.
How about this?

[Passaloutre]

The LED shouldn't be in the signal path, or even remotely connected to it. Use a DPDT, one pole does the tone switching, and the other lifts the ground of the LED. Quackzed's schematic above is exactly correct, just omit the resistor above the number three.

[anotherjim]

Yes, exactly what Russ (Cozybuilder) drew! Reply #8.
Sorry Russ, in my haste I didn't see your post.

Note that Russ also shows the Tone switch indicator LED's doing double duty as a pedal bypass indicator, which is a smart move. But if you don't want that feature, then SW1B tag C is wired to 0v.