What 3pdt wiring do you use; why?

[mikemaddux]

Im sorry if im out of the loop here, but what is the tonal difference?!?!?

I use the EZ style of wiring 3pdt and never have a problem with switches popping....

What are ALL of the advantages of a "grounded input"
Ive built high gain pedals and never had oscillation....

The other version looks so much more complicated.

[Projectile]

Im sorry if im out of the loop here, but what is the tonal difference?!?!?

I use the EZ style of wiring 3pdt and never have a problem with switches popping....

What are ALL of the advantages of a "grounded input"
Ive built high gain pedals and never had oscillation....

The other version looks so much more complicated.

+1

I'd like to know as well. I've never had a problem with the EZ style 3pdt wiring. The only advantage I see is that it would allow you to get rid off the initial 1M pull down resistor in a lot of circuits. Other than that, it just seems pointlessly complicated. I would think that if your design includes the 1M pulldown resistor before the input cap, then there would be no reason to use the input grounded wiring scheme. However, I've seen builds that use both! I'm no expert though, so maybe others could chime in on this one.

[davent]

I believe grounding the input is done to help suppress oscillations that sometimes occur when certain high gain circuits are bypassed and then bleed into other circuits.

dave

[Mr. G.]

I use roughly the same wiring as the tonepad version.  I do this because when I built my first pedal (a true bypass loop pedal), the first loop was strictly for sending the signal to a tuner pedal.  It was first wired with the input ungrounded, and I got some bleedthrough.  It was only noticeable if the gain was up on my amp, or I had a distortion pedal on.  After that, I rewired the switch so that the input was grounded, and there was no more bleedthrough.  So, I've been wiring things like that ever since.

[punkin]

I use the one from tonepad's offboard wiring pdf which allows for an led. I don't see a lot of people using this method, so i was wondering what are the other methods and what are their advantages? Here's a pic of the method I use:

Thanks!
-Sam

That's the one I use...easy and gets the job done.

[Projectile]

I believe grounding the input is done to help suppress oscillations that sometimes occur when certain high gain circuits are bypassed and then bleed into other circuits.

dave

Ahh, that makes sense. I've never had that happen, but I see now how bleed in high gain situations could cause a problem. I always thought it was just a pop prevention measure. Thanks for clearing that up guys.  All my distortion and OD pedals will get this wiring scheme from now on. 

[danielzink]

I've used this for all but 1 or 2 pedals - not too different from the tonepad style.





Dan

[Andi]

[Projectile]

Alright, so basically we still have the same 2 versions that are in the FAQ: "Standard" and "grounded input."

Everything posted here appears to be simple rearrangements of the same 2 basic wiring diagrams.

[Paul Marossy]

I believe grounding the input is done to help suppress oscillations that sometimes occur when certain high gain circuits are bypassed and then bleed into other circuits.

Since I starting building things towards the end of 2001, there are only two times that I have used the grounded circuit input in a guitar pedal. One of those was in my Shaka Tube build because it would oscillate in bypass mode and that somehow found its way into the signal path when in bypass mode - it was like a whining sound, IIRC. I still don't know exactly how that was happening, but the grounded circuit input method fixed it.

[snap]

it should be standard!

[bumblebee]

I use a version I came up with, i've only seen a few people use it and there's no diagram online of it. It has grounded input and regardless or not if you use a DPDT you still have grounded input.. When you use a 3PDT all grounds (LED/INPUT) are connected together.

[Projectile]

I use a version I came up with, i've only seen a few people use it and there's no diagram online of it. It has grounded input and regardless or not if you use a DPDT you still have grounded input.. When you use a 3PDT all grounds (LED/INPUT) are connected together.

How can you have grounded input without a DPDT? Are you sure it's not just a reorganized version of the one that's been posted here a dozen times? In the standard input grounded wiring scheme all grounds are also connected together.

[Mugshot]

when you ground the input you effectively shut the circuit down, similar to turning it off. so basically the effect is off when the input is shunted to ground.


grounding the input using DPDT is possible, without an LED it is very obvious; using millenium bypass it is also the same.

[Andi]

when you ground the input you effectively shut the circuit down, similar to turning it off. so basically the effect is off when the input is shunted to ground.

The circuit is still on and still drawing current. If you grounded the circuit input but connected the output to an amp you'd still, for instance, hear any noise generated by the circuit. Grounding the input is more to prevent the circuit from squealing or oscillating as some high gain circuits can.

[bumblebee]

I use a version I came up with, i've only seen a few people use it and there's no diagram online of it. It has grounded input and regardless or not if you use a DPDT you still have grounded input.. When you use a 3PDT all grounds (LED/INPUT) are connected together.

How can you have grounded input without a DPDT? Are you sure it's not just a reorganized version of the one that's been posted here a dozen times? In the standard input grounded wiring scheme all grounds are also connected together.

You cant WITHOUT a DPDT, LOL. You can have grounded input with a DPDT easily enough though.

[Projectile]

I use a version I came up with, i've only seen a few people use it and there's no diagram online of it. It has grounded input and regardless or not if you use a DPDT you still have grounded input.. When you use a 3PDT all grounds (LED/INPUT) are connected together.

How can you have grounded input without a DPDT? Are you sure it's not just a reorganized version of the one that's been posted here a dozen times? In the standard input grounded wiring scheme all grounds are also connected together.

You cant WITHOUT a DPDT, LOL. You can have grounded input with a DPDT easily enough though.

Ummm..... you said, quote: "It has grounded input and regardless or not if you use a DPDT you still have grounded input." Re-read what you typed. It doesn't make any sense. You are directly contradicting yourself.

[Mugshot]

when you ground the input you effectively shut the circuit down, similar to turning it off. so basically the effect is off when the input is shunted to ground.

The circuit is still on and still drawing current. If you grounded the circuit input but connected the output to an amp you'd still, for instance, hear any noise generated by the circuit. Grounding the input is more to prevent the circuit from squealing or oscillating as some high gain circuits can.

1) andi, when the circuit is bypassed, isnt the output disconnected already from the signal line? please shed some light here

2) also, is it okay to add pulldown resistors to the output of the circuit when bypassed? because i do this to all my pedals that use 3pdt to help eliminate pops if possible.

3) since most circuits already have pulldown resistors for the input, what benefit can we get if we also wire the circuit to have the input shunted to ground when bypassed? from what i see there is already a ground loop in that setup.

[Projectile]

1) andi, when the circuit is bypassed, isnt the output disconnected already from the signal line? please shed some light here

Yes, but you can still get bleedthrough if you have something very loud like an opamp oscillating in the disconnected circuit. The circuit isn't actually off until you disconnect V+ or ground from the active components. It can still amplify noise, and it can still become unstable and oscillate

2) also, is it okay to add pulldown resistors to the output of the circuit when bypassed? because i do this to all my pedals that use 3pdt to help eliminate pops if possible.

I don't see any problem with adding a pulldown resistor to the output. As long as it is a high enough value, like 1M, it shouldn't load down the output enough to make any difference in the signal.

3) since most circuits already have pulldown resistors for the input, what benefit can we get if we also wire the circuit to have the input shunted to ground when bypassed? from what i see there is already a ground loop in that setup.

That's exactly what we just spent the last page of this thread discussing. I asked the same question at the top of the page. No offense, but where have you been man? Sleep in class much? 

from above:

I believe grounding the input is done to help suppress oscillations that sometimes occur when certain high gain circuits are bypassed and then bleed into other circuits.

dave

Ahh, that makes sense. I've never had that happen, but I see now how bleed in high gain situations could cause a problem. I always thought it was just a pop prevention measure. Thanks for clearing that up guys.  All my distortion and OD pedals will get this wiring scheme from now on. 

I use roughly the same wiring as the tonepad version.  I do this because when I built my first pedal (a true bypass loop pedal), the first loop was strictly for sending the signal to a tuner pedal.  It was first wired with the input ungrounded, and I got some bleedthrough.  It was only noticeable if the gain was up on my amp, or I had a distortion pedal on.  After that, I rewired the switch so that the input was grounded, and there was no more bleedthrough.  So, I've been wiring things like that ever since.

Since I starting building things towards the end of 2001, there are only two times that I have used the grounded circuit input in a guitar pedal. One of those was in my Shaka Tube build because it would oscillate in bypass mode and that somehow found its way into the signal path when in bypass mode - it was like a whining sound, IIRC. I still don't know exactly how that was happening, but the grounded circuit input method fixed it.

The circuit is still on and still drawing current. If you grounded the circuit input but connected the output to an amp you'd still, for instance, hear any noise generated by the circuit. Grounding the input is more to prevent the circuit from squealing or oscillating as some high gain circuits can.

[Mugshot]

3) since most circuits already have pulldown resistors for the input, what benefit can we get if we also wire the circuit to have the input shunted to ground when bypassed? from what i see there is already a ground loop in that setup.

That's exactly what we just spent the last page of this thread discussing. I asked the same question at the top of the page. No offense, but where have you been man? Sleep in class much? 

hehe, probably i was reading too fast   

thanks for the replies man, now i have a pretty solid idea what the application of the techniques makes to stompbox wiring