Author Topic: Adding a +V-powered buffer to a -V pedal (PNP fuzz)  (Read 212 times)

aion

Adding a +V-powered buffer to a -V pedal (PNP fuzz)
« on: August 25, 2019, 06:11:53 PM »
I'm adding Jack Orman's transformer-based pickup simulator to the front of a Tonebender to allow it to be used later in the chain if desired. I'm also throwing a JFET on the front to fully isolate the impedance from anything earlier in the chain, as in the EQD Eruptor.

Schematic:



As you can see, I'm using an inverter to get -VA, so I already have both the positive and negative supplies handy. Will this cause any issues as drawn, or is it kosher since the two stages are capacitor-coupled and the AC signal is indifferent?

I've used the pickup sim with negative-ground pedals like the Woolly Mammoth and it works great, but just wanted to check before migrating it to positive-ground.

I realize I can probably set up the JFET to run on negative-ground like the rest of the circuit, but am also working on a different idea where I run both an NPN silicon and PNP germanium fuzz in parallel, so I would have to work through it eventually I guess.
Aion Electronics - DIY PCB projects for classic and obscure circuits

PRR

Re: Adding a +V-powered buffer to a -V pedal (PNP fuzz)
« Reply #1 on: August 25, 2019, 10:49:33 PM »
R10 should be much less than 1Meg.

DC voltage on Source should not get to next stage.

More RPDs may pop less.


aion

Re: Adding a +V-powered buffer to a -V pedal (PNP fuzz)
« Reply #2 on: August 25, 2019, 11:00:55 PM »
Yes, sorry, that was a mistake I forgot to correct - I had just duplicated the resistor part and missed the value. Itís intended to be 4.7k!
Aion Electronics - DIY PCB projects for classic and obscure circuits