Wiring Diagram For Varitone Guitar

[sullus]

I'm planning the wiring for a jazzmaster that I'm putting together. Just want to make sure I've got everything right before I start soldering. Especially the Varitone circuit... this is my first time using a rotary switch.

Pulling out the push/pull should give the "notched" sounds of a true varitone. Pushed in, it acts like a standard tone control, using whichever capacitor is selected on the rotary. Other than that, it's a pretty straighforward 2 pickup into 1 volume setup, with a killswitch.

[bigdguitars]

that looks about right.

[lovekraft]

If you have problems with the switch popping when you change caps (you won't know until you've got it all wired up, unfortunately), simply install a 10 Meg resistor between the switch common lug and each cap's switch lug - if it doesn't pop, then I think you've got a winner there! BTW, nice diagram!!

[VanKirk]

Maybe instead of the topic reading "Wiring Diagram For Varitone Guitar, does it check out?",

it should say "Wiring Diagram for a Varitone Guitar" and get pinned?

[perhellion]

I agree, with all the Varitone questions, this should be pinned.

I don't understand what the push/pull pot is changing (or how exactly is it different than just a tone pot?).

And Lovecraft, exactly where does the 10 meg resistor go?

[bigdguitars]

techinally its a pop, but in reality if you get a make before break switch there is no pop...

With a break before make switch there is a slight pop, like switching pickups its not loud or annoying at all...

[sullus]

Thanks for the responses guys. Of course you have my permission to pin it, copy it, use it... whatever. I'm just happy it's going to work.

I don't understand what the push/pull pot is changing (or how exactly is it different than just a tone pot?).

Perhellion, with the switch pushed in, it is just a tone pot, only you can select which value capacitor it uses. When the switch is pulled out, it becomes a "notch filter". Instead of low passing everything like a normal tone control, it deletes a narrow band of frequencies from the signal. You can set which frequencies by switching capacitors. It's sort of like a wah wah pedal... actually it's the exact opposite. Wah pedals boost certain frequencies, and the varitone cuts them.

If you have problems with the switch popping when you change caps (you won't know until you've got it all wired up, unfortunately), simply install a 10 Meg resistor between the switch common lug and each cap's switch lug - if it doesn't pop, then I think you've got a winner there!

Thanks, I'll definitely be doing that if it pops. I might want to do something similar on the kill switch, since I'm using it just for manual tremolo effects, and I don't want it popping when I switch it on and off rapidly. In that case, would I wire the resistor between the input lug and groud lug, or input lug and common lug?

techinally its a pop, but in reality if you get a make before break switch there is no pop...

I'm using an Allparts Rotary Switch, 6-Position, 4-Pole. Can anyone tell me if it's make before break?

Edited May 11, 2005 by sullus

[bigdguitars]

its hard to describe look at the switch where it makes the connection. If it looks like it goes metal to metal then its the right one. If you see plastic in between the metal pieces then its break.

If you add that 10meg resistor it will make the varitone a lot quiter. you will need to add a larger choke and all of that...

I have been through this enough... =)

[sullus]

Ok, cool... looks like metal to metal, so I should be ok.

[lovekraft]

If you add that 10meg resistor it will make the varitone a lot quiter. you will need to add a larger choke and all of that...

How can that be? The total resistance at any switch position will be paralleled with a dead short, effectively eliminating any load on the choke, and the voltage divider effect will effectively isolate the other caps from the ground path - they've been using this passive EQ setup in studio equipment since the 30s without issues. Unless the inductor you're using has an extremely high resistance, I don't see how it could have any effect at all. Don't misunderstand me, I'm not calling you out or anything, but I would truly like to know what's going on to cause that, because it goes against both what little electronics knowledge I have and my own experiences - I've never had a problem using pulldown resistors to quiet switching when there's a potential for DC chargeup in a floating cap.

[bigdguitars]

Ahh I re-read your post. I was playing with something else that drained my vol... I see what you are doing and you are correct. I was playing with something else when I had my problems...

[perhellion]

From the response, I can clarify my question. I understand what happens on "push" - tone control and on "pull" - notch filter -- but I don't get how this happens. I thought push/pull pots were just a pot plus a two-way switch. Is the switch simply controlling whether or not the inductor is being used?

[lovekraft]

That's it! Without the inductor in series, it's simply a standard tone control (with selectable caps).

BigD, thanks for that gracious reply - I didn't mean to sound like a know-it-all or anything, but if you had had probems with pulldown resistors interacting with the inductor, I was going to have to seriously rethink one of my current projects. Thanks for clearing that up.

[perhellion]

So when the push/pull pot puts the inductor in series, does turning the knob do anything?

[lovekraft]

The tone pot works exactly the same in either position, varying the amount of signal attenuation. What changes is the nature of the filter itself - with the inductor in the circuit, instead of simply cutting highs, it cuts a fairly narrow band in the midrange.