Two Pots To A 3PDT Toggle Switch

[Ric046]

Hi, I've tried on a couple of projects to wire two pots to a 3PDT toggle switch in order to switch between, for example two gain pots or two volume pots and I always seem to get this loud click/squeal as I switch the switch. So I must be doing something wrong, but I can't for the life of me figure out what!

I simply wire holes 1-3 from the PCB to the three central pins of the 3PDT, and then lugs 1-3 of the two pots to the two sets of pins on the outside of the 3PDT. Simples. Everything works as it should apart from this click/squeal during the switching process.

In this lastest case I'm switching between two frequency pots on my 'Karate Shop' build. In this case, as far as I can make out, the signals coming in to lug 1, lug 2 & 3 are connected together as the signal goes out to gnd.

Cheers
Ric

[Nate77]

Maybe a resistor (68k ??) between pins 1 & 2, and another between pins 2 & 3. I would use an 1/8 watt just for space availability. This pot switching thing is pretty clever! I've never thought about that. Good work man. I hope this helps.

[Ric046]

Hi nate, yep it's cool. Do it with a 3PDT footswitch and you can switch between two settings while playing. I found some stuff on another forum on how to wire up in this situation

http://www.ilovefuzz.com/viewtopic.php?f=151&t=18767 check a couple of posts down.

But this doesn't quite work for my situation.

Please could you give me a little more info. When you say 'a resistor between pins 1 & 2', do you mean the pins 1 & 2 of the central 3 pins of the 3PDT or 1 & 2 of each set of 3 pins on the switch?

Also would connecting pins 1 & 2 not mess up the circuit as 1 & 2 are only connected through the pot.

I'm confused!

[mysticaxe]

If one of the pins goes to ground, I would leave it connected all the time.  You could then use the 3rd row for an LED to let you know which pot is active...

[Ric046]

Hi. None of the pins go direct to gnd unfortunately.

Its the frequency pot of the karate shop if you want to take a look at the schematic.

2 & 3 eventually go to gnd so I could keep these two connected all the time?

[DutchMF]

Maybe you should get one of these:

http://www.guitarpcb.com/apps/webstore/products/show/3436270

I have one that I haven't been able to use in a build yet, but I'll report back when I do.

Paul

[Ric046]

I've got some of those '2 Knob Jobs' from GuitarPCB. They're very good, but unfortunately they don't fit 3PDT toggle switches.

[Gledison]

Maybe you should get one of these:

http://www.guitarpcb.com/apps/webstore/products/show/3436270

I have one that I haven't been able to use in a build yet, but I'll report back when I do.

Paul

This look pretty cool! But how does it work to switch off? Or i understood wrong;-S?

[DutchMF]

Switching the effect off would be done with another, separate 3PDT. This board only switches between 2 pots, for preset volume levels/delay times/chorus depths etc..... Kinda cool, actually, mine is going in a porkbarrel that I wanted to do something similar with, but never got working properly.

Paul

[Gledison]

Switching the effect off would be done with another, separate 3PDT. This board only switches between 2 pots, for preset volume levels/delay times/chorus depths etc..... Kinda cool, actually, mine is going in a porkbarrel that I wanted to do something similar with, but never got working properly.

Paul

daaaaaaa! that's make sense!
now that u mentioned, just finished my porkbarrel. still wondering how to get the best out of it.

[Nate77]

If you're looking at the bottom of the 3pdt it would be numbered ; 147
                                                                                                 258
                                                                                                 369
So I was thinking an 1/8 watt 68-ish resistor may eat up some of that squeal. So in retrospect, it would be pins 1 and 3, and also pins 7 and 9. I'm thinking that what you are experiencing is the monetary simultaneous contact of the switch. The resistors would be acting similar to a pull down resistor. YOu may need to use a much larger value. Good luck man. Let me know if this helps

[Ric046]

No good Nate. I tried it out with two 120k's, still getting the loud click with no audiable difference.

Cheers for trying to help me out.