Pedal build help needed: NPN or PNP?

[Blue Calx]

I'm building a Fender Blender from this schematic:

http://fuzzcentral.ssguitar.com/blender.php

I want to add true bypass and an LED with a 3PDT switch like I have done with other builds, but in the past, I have used project files that walk a noob like me through every step of the build. This project assumes a little bit of electronics knowledge, and I am still learning.

I have found the following diagrams for wiring true bypass with LED:


and



I'm assuming, since the transistors used in this circuit are NPN transistors, that I will use the NPN version of this diagram. Also, since this circuit seems to use a negative ground (please excuse any misuse of terminology, like I said, I'm still learning), I'm leaning more toward the NPN version.

Am I correct, or will I screw everything up if I proceed as planned?

Thanks for any help you can offer!

[Blue Calx]

Re: Pedal build help needed: NPN or PNP?

Oh, also...

I have built other pedals with a different 3PDT true bypass setup where the circuit input was switched to ground when the bypass is switched. Is there any advantage of this setup over those pictured above where the circuit input is simply not connected to anything in bypass mode?

[glassman]

Re: Pedal build help needed: NPN or PNP?

I'm assuming, since the transistors used in this circuit are NPN transistors, that I will use the NPN version of this diagram. Also, since this circuit seems to use a negative ground (please excuse any misuse of terminology, like I said, I'm still learning), I'm leaning more toward the NPN version.

Am I correct, or will I screw everything up if I proceed as planned?

Thanks for any help you can offer!

The NPN version will definitely work better with a power supply...you may plan on a battery for now but it never hurts to think ahead.

Oh, also...

I have built other pedals with a different 3PDT true bypass setup where the circuit input was switched to ground when the bypass is switched. Is there any advantage of this setup over those pictured above where the circuit input is simply not connected to anything in bypass mode?

A ground reference in spite of switch position will help to reduce or eliminate the "pop" that can occur when switching from bypass to boost. Even some 10 meg resistors placed across the contacts help a lot. The idea is to eliminate the possibility of any DC potential at any contact.

[Blue Calx]

Re: Pedal build help needed: NPN or PNP?

Thanks! I wired it up NPN and it works... but it sounds like hell. I've read that this pedal is supposed to be nigh untameable. I'll have to play around with it to make sure I can get some usable sounds.