transistor substitutes

soulsonic · Post by **soulsonic** » 12 Mar 2009, 05:45

Why are you posting this here?! This kind of topic should go in the "Workbench" or "How-To" section.

I've been using Russian MP13B in Rangemasters with good results - low noise, low leakage, and very consistent. And they're cheap.

In Fuzz Faces, I've done AC128, AC188, and GT308. But it's hard to find good 128/188 anymore... almost all too noisy or leaky. Though, I've built some very nice FF with very leaky 188 before. As long as you get the bias trimmed right, they seem to do their job fine.

Scruffie · Post by **Scruffie** » 30 Mar 2009, 12:22

Just thought i'd mention that i got good results with the BC558B Silicon Transistor as a good replacement for The Ge AC128's in my Fuzz Factory also i'm sure its listed elsewhere but heres a link to a page with some substitutes. http://www.aronnelson.com/gallery/main. ... T.gif.html

Scruffie

HydrozeenElectronics · Post by **HydrozeenElectronics** » 31 Mar 2009, 00:35

soulsonic wrote:Why are you posting this here?! This kind of topic should go in the "Workbench" or "How-To" section.

I've been using Russian MP13B in Rangemasters with good results - low noise, low leakage, and very consistent. And they're cheap.

In Fuzz Faces, I've done AC128, AC188, and GT308. But it's hard to find good 128/188 anymore... almost all too noisy or leaky. Though, I've built some very nice FF with very leaky 188 before. As long as you get the bias trimmed right, they seem to do their job fine.

I have been thinking about picking up some of those GT308's but some are: GT308a and GT308v which should I go for or are they both good?

Thanks

Scruffie · Post by **Scruffie** » 31 Mar 2009, 00:47

Ok this isn't quite what you were after but may be useful to you or atleast some, its an explanation of russian markings on transistors such as the GT308a but i will keep looking to find out the difference, however if my memory serves correct about seeing those transistors the a version is better ( just dont hold me to it )

Link to a PDF
http://www.ok1rr.com/e107_plugins/pdf/p ... content.28

Thanks and i hope this helps, i will keep looking for a definitive answer

Scruffie

Scruffie · Post by **Scruffie** » 31 Mar 2009, 00:58

By the by i like to show my appreciation to every reply i get, thanks for the thank you biffa, i'l do my best to keep 'em coming and am as we speak scouring the internet for useful info.

playon · Post by **playon** » 31 Mar 2009, 03:43

I lucked out and scored a few hundred US-made 2N1307 germaniums off of ebay in January for dirt cheap, and they sound great in fuzz boxes. I built up a two-tranny Tonebender clone that worked great with them. They are in the higher gain range, 60-300 hfe (with most in the 80-180 range) but the leakage is very low, I'm only finding 15% or so that aren't good - much better ratio than most of the European ge trannys I've bought. The ones I have were marked Trans-Tek but they were also made by Texas Instruments, GE. Newmarket and others. They are quiet and have a warm, even sound, not as edgy as some. I think they came out as a high-gain replacement for the 2N404. The other one to look for is the 2N1308 which is the NPN version. The even numbers are NPN, the odd are PNP, so you can also look for 2N1306, 2N1305, etc

Datasheet:

http://www.datasheetarchive.com/search.php?q=2n1307

http://www.datasheetarchive.com/search.php?q=2n1308

Electric Warrior · Post by **Electric Warrior** » 06 Apr 2009, 15:46

Biffa kindly sent me some great transistors. I threw in a few more to make a big shootout. here's what I think about them in a Rangemaster:

oc44 mullard yellow jacket: this one has it all - thick, rich, full and creamy sounding with a big but well defined low end, not woofy. really inspiring. this one's my favourite.
oc82dm: awesome, has a distinct barking sound going on, very different character compared to the other oc types
oc82: another great one. very full sounding, but not as creamy as the yellow fellow
oc47: similar in character to the oc82, but with less high end. not as hot sounding
oc74: kinda weak, I don't like it too much
oc71: glassy on top, nice sparkle. most transparent sounding of the bunch. a bit weak, I think the second one Biffa sent me is a bit hotter
2sb172: nice and full, well defined, but in a different way than the oc types. mids sound a bit scooped.
oc44 Philips black glass: rather big low end, but can be a bit woofy. I still percieve it as well balanced. not as rich sounding and well defined as the yellow jacket.

as a little bonus I recorded a little soundclip. I played two riffs with each transistor: click
all were biased as close to 7V as possible.

Scruffie · Post by **Scruffie** » 06 Apr 2009, 16:57

Nice post, good descriptions, lucky too as the parts for my rangemaster ( actually a javaboost ) comes tommorow and i just got a set of old radios to harvest parts out of and have the choice of OC81's, 74's, 44's etc and wasnt sure which to pick, also dunno if anyones heard of it but i have an Ediwan PXB103 PNP Black Top hat Cap style transistor and wondered if anyone has any info or experience with it? i read they were meant to have an hFe of around 45-100 but thats the best i got.

Many Thanks,
Scruffie.

Electric Warrior · Post by **Electric Warrior** » 06 Apr 2009, 21:11

never heard about these. can't hurt to try them.

Electric Warrior · Post by **Electric Warrior** » 07 Apr 2009, 06:48

it's so hard to decide with that many different flavours

Scruffie · Post by **Scruffie** » 16 Apr 2009, 22:35

Dunno if it's any use to anyone and it's not quite a transistor substitute but it is a data sheet of every OC Ge Transistor with PNP or NPN listing, values & ratings and notes on there uses e.g. Switching, Audio Amp So on.

And as for my mystery Ediswan Transistor i found this page on them for anyone that may find one aswell,
http://homepages.nildram.co.uk/~wylie/E ... diswan.htm

Scruff.