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Projects => Tech Help - Projects Page => Topic started by: Sam87 on August 08, 2010, 05:06:12 PM

Title: NPN zombii
Post by: Sam87 on August 08, 2010, 05:06:12 PM
Hi guys

I have obtained a load of ac127 Npn trainnies and have two Mached germanium npn trannies left I've from a previous build

Would I be right in saying that to use these trannies in a zombii circuit I would just need to wiring all positives to the negative and visaversa?

My previous build have all been pnp but would like to try and use up the npn I have lying around

Thanks in advance
Title: Re: NPN zombii
Post by: madbean on August 12, 2010, 03:38:20 AM
The circuit is already negative ground, so you should not have to do anything. I would pop in a couple of regular bi-polars first to see what happens. Try some 2n3904's first.
Title: Re: NPN zombii
Post by: Sam87 on August 13, 2010, 09:03:19 AM
I know this is a noob question but how does a meg ground pedal work with pnp trannies
Title: Re: NPN zombii
Post by: lbrooks on October 14, 2010, 03:16:00 PM
The Schematic calls for Germanium PNP Trans.  but if I'm not mistaken the 2n3904's are Silicon NPN.  Should I use the 2n3906, that looks to be PNP?
Title: Re: NPN zombii
Post by: madbean on October 14, 2010, 03:25:00 PM
Quote from: Sam87 on August 13, 2010, 09:03:19 AM
I know this is a noob question but how does a meg ground pedal work with pnp trannies

PNP trannies can work with either negative or positive ground configurations. Negative ground schems can lead to oscillation and motorboating from the trannies, so these kinds of fuzzes are generally built positive ground.
Title: Re: NPN zombii
Post by: madbean on October 14, 2010, 03:26:27 PM
Quote from: madbean on October 14, 2010, 03:25:00 PM
Quote from: Sam87 on August 13, 2010, 09:03:19 AM
I know this is a noob question but how does a meg ground pedal work with pnp trannies

PNP trannies can work with either negative or positive ground configurations. Negative ground schems can lead to oscillation and motorboating from the trannies, so these kinds of fuzzes are generally built positive ground.

Yep, exactly right. The 2n3906 is PNP---I was mistaken in saying 2n3904. I have my transistors socketed on this so I will try a couple of those and see what happens.