Chandler - Germanium Drive

devastator · Post by **devastator** » 10 May 2012, 18:29

a "preamp" boost using a germanium transistor .It seems to be a variant of the chandler germanium preamp for guitars . It's seems to be original (talking about "feedback" path in the circuit ) at least we can hope for not another Rangemaster clone.

the "preamp" version :

http://www.soundonsound.com/sos/nov06/a ... andler.htm

Jarno · Post by **Jarno** » 11 May 2012, 17:54

That block might be a discrete opamp containing Ge transistors, maybe not that different from their studio equipment.

okgb · Post by **okgb** » 12 May 2012, 14:24

18v's or +/- psu with two batteries , maybe they adapted the module gain/block from their mic pres / eq's
feedback may be overall level control , Germanium drive , nice word combo or do they mean road with flowers ?

Hey , gut shot , seems to show one pot in the middle ? not two ?

Chrome Dinette · Post by **Chrome Dinette** » 14 May 2012, 10:32

The guts show different units, from when they were still prototypting.

I have the non-ge pedal(Little Devil) and the black block is one solid piece that plugs into the pcb with 5 pins.

I read somewhere else, but I don't know how true it is, that this is similar to the gain amp of an RCA BA-31a:

http://www.waltzingbear.com/Schematics/RCA/BA-31A.htm

RnFR · Post by **RnFR** » 14 May 2012, 11:23

so feedback pot would be R4/R7, and gain pot on the input? btw- the 3391 is a silicon transistor, driving the Ge 404. not sure about the others. if you can remember where you read that, please make sure to post. it might be fun to try this out with +/-9v. and those battery holders are slick!

Chrome Dinette · Post by **Chrome Dinette** » 14 May 2012, 11:34

It was a post on tgp, and there wasn't really any more info. I can try and find the post a little later.

Chrome Dinette · Post by **Chrome Dinette** » 14 May 2012, 11:38

Oh, the black module in the non-ge version is labelled "altran c444 gain" or something like that.

RnFR · Post by **RnFR** » 14 May 2012, 11:40

no worries. I did some digging.

http://www.groupdiy.com/index.php?topic=28210.0

in particular this excellent breakdown by PRR.

http://www.groupdiy.com/index.php?PHPSE ... #msg341628

edit: ahhhh!!!! Fukin Hell. that schem is labeled 31A, but is really 31C! apparently the A model is a 6tr all Ge version. I should really finish digging before posting!

Chrome Dinette · Post by **Chrome Dinette** » 15 May 2012, 00:47

There is a BA-31A on ebay with a clear pic of the PCB.

devastator · Post by **devastator** » 19 Aug 2012, 21:15

news !!

who has a spoon to take off all that black goop with the box ?

taken at TGP