Fuzz Polarity... Flip?

[Mike Vilogi]

Hello,
          I am writing to ask a bit about NPN and PNP polarity. I get that I can use traditional wall warts with NPN fuzz, but is there a way to use PNP and still be able to use a standard power supply? IE, flip the polarity? I have built 2 fuzz so far, both NPN, and want to make a MOsrite Fuzzrite Clone next, but NPN germ is just too $$ and too few to choose from.

       

[smallbearelec]

Hi Mike--

is there a way to use PNP and still be able to use a standard power supply? IE, flip the polarity?  

If building PNP, yes, you would flip the power supply so that the positive side is grounded. Realize, however, that if you combine positive- and negative- ground pedals on your board, you can't power both from the same supply; you would then need separate supplies, one positive-ground and one negative ground.

I have built 2 fuzz so far, both NPN, and want to make a Mosrite Fuzzrite Clone next, but NPN germ is just too $$ and too few to choose from.

Now for the good news: Robert Jones (he goes by Codemonk here) just finished and tested a layout of the Fuzzrite for me. You can find it the Gallery:
http://www.aronnelson.com/gallery/main.php/v/Small+Bear+Electronics/

The Fuzzrite does not require expensive, low-leakage germanium. Try a 2N2430 for Q1 and a 2N649 for Q2. If you want an assortment of NPN Ge in the 50s that would provide a number of choices for Q2, that's also available, my SKU 0114F.

Regards
SD

[tommycataus]

Exactly what Smallbear elec said.

You can also get hold of voltage inverter circuits which will allow you to power both positive and negative ground pedals from the same supply such as madbean's road rage. However, make sure you have a good power supply and check your wiring as I have had a few problems. The foolproof way is to use a dedicated power supply, and the current draw is low for fuzzes so batteries are a safe bet if you are up for it.

[nocentelli]

It is also possible use pnp transistors in a fuzzface circuit, but with positive power connected to the emitters and ground connected to the collectors - In this way, you can also power it alongside other standard negative ground pedals on the same daisychain: Here is the schem for the Lovepedal "Silicon Fuzzmaster" that uses this method -

[italianguy63]

I have voltage inverter boards that do this in the "sale" section made especially for this scenario.  Or, you can PM me if interested. 

Personally, I like the voltage inverter selection, because it makes the positive ground PNP pedals compatable with the modern negative ground pedals on the same pedal board using the same power supply....

MC

[R.G.]

It is also possible use pnp transistors in a fuzzface circuit, but with positive power connected to the emitters and ground connected to the collectors - In this way, you can also power it alongside other standard negative ground pedals on the same daisychain:

It is indeed possible. However, this method sometimes unpredictably produces oscillation that cannot be cured by methods other than un-converting the power supplies. It works often enough to keep people suggesting it, but every so often it doesn't.  It's kind of a self-built trap for beginners.

[nocentelli]

I know, I thought of your advice from the past on this matter when I posted it: It amused me to link to a commercial pedal made by someone who was obviously not well aquainted with the oft-repeated wisdom or rg keen.