Negative ground for PNP Rangemaster

[jaysg]

I've seen that there are issues with negative ground PNP fuzz faces and R.G.'s advice to build positive ground PNP FF's.  Is the Rangemaster also a problem, or is less so, with only one transistor?  (I'm still in the parts gathering phase.)

thanks ahead

[TheBigMan]

Same problem.  Using PNP trannies with negative ground or vice versa can cause all manner of weird issues.  Sometimes they work perfectly, sometimes they don't.  I'd try getting a hold of some NPN Ge transistors.  I've been using CV7112s recently with good results.  Aron sells them, Small Bear have them too.

[jaysg]

Hmm...I'm concerned with wiring the DC socket.  Fuller uses a positive center adapter for his PNP FF and others.  I guess I'd like to see a drawing. 

[hairyandy]

Jay,

Here's a link to a stripboard (vero) layout that I did for a PNP negative ground Rangemaster in the layout gallery:

http://aronnelson.com/gallery/album26/Rangemaster

I haven't had any issues at all.  Make sure you have a good transistor and make sure your ground is good and everything should be fine.  I just built two of these for guys touring with the Black Crowes and with John Mayer and they play them every night with no problems.  This is one of my favorite sounding circuits.

Good luck,

Andy

[zjokka]

you can made a really good a better rangemaster NPN negative ground by piggybacking SI transistor for lower gain. Consider it, really. Search for 'piggyback'

http://www.diystompboxes.com/smfforum/index.php?topic=37861.0

http://www.diystompboxes.com/smfforum/index.php?topic=49543.0

http://www.diystompboxes.com/smfforum/index.php?topic=21801.0

Ive got heaps of gold leg 2n404as that I don't use, just because PNP and hence better is positive ground and hence incompatible with the rest of the chain.

let us know how goes
zj

[col]

I have used a negative goround pnp one for ages and have had no trouble. It was one of the first pedals I built and has been in constant use ever since. After putting a 3PDT switch in I have an indicator, I have never been able to get the millenium bypass to work with a negative ground pnp circuit.
I have had trouble with oscillation with neg. ground pnp circuits but never when using a power adapter, just batteries even when fully charged. Maybe I've been lucky so far!

[jaysg]

Thanks all.  I will go with a negative ground config.

I emailed J.D. at GGG about his designs since I was confused about DC adapters.  His stuff all works off of center negative/barrel postitive whether or not it's PNP and/or positive ground.  This is different than Fuller and probably others who mate center postitive/barrel negative to PNP designs.  Very confusing...well...I was confused.  ymmv