I've built a transistor-based distortion pedal which has switchable transistors. I've been playing around with what transistors to use in it and currently have a 2n3904 and a BC109C. They both sound good but are maybe a bit too similar to one another to make having the switch worthwhile. The 2n3904 has the greater gain of the two and can border on fuzz, the BC109C is more overdrive/distortion.
I did buy a 2n1304 but it was really low gain, could get it to distort a bit at max everything and you could hear that nice round germanium Tone, but it was just too low gain to be of real use.
So what I'm looking for is a, not stupidly priced, NPN germanium transistor with a gain that would be in the range of the 2n3904. Can anyone recommend some that might be suitable.
Try an AC176. They are relatively common.
Quote from: tonyharker on January 09, 2020, 06:04:16 PM
Try an AC176. They are relatively common.
Thanks, will do!
You could make a Sziklai Pair with a 2N3906 PNP.
Quote from: bushidov on January 09, 2020, 08:15:33 PM
You could make a Sziklai Pair with a 2N3906 PNP.
I had to look up what a Sziklai pair was, interesting concept. Which transistor were you suggesting pairing with the 2N3906, a 2N3904?
The purpose of Sziklai pair is to "simulate" Darlington's high gain counting for only one VBE, which for Si is about 600mV...
(in theory at least, 'cause p-n-p's always exhibit lower that their complementary n-p-n's gain..)
So, one bias issue (same VBE voltage drop) is settled with Sziklai pair and maybe also another bias issue (bias configuration practically independent of individual transistor gain) but lower Ge's VBE drop should remain.. :icon_wink:
if you insist for high gain Ge replacement, it should be interesting enough to evaluate a Drarlington pair consisted of 2 Ge of low enough gain..(e.g. http://smallbear-electronics.mybigcommerce.com/low-gain-germanium-npn-under-40-bag-of-5/ )
(total VBE almost the same of a single Si BJT and current gain similar to high gain Si BJT..)
The 2n1306 and 2n1308 are in the same family but higher gain, if enough for you I can't say. I just found a genuine RCA 2n2613 and it has very high gain over 200. They are not easy to find though. If you want a old TI npn germ, let me know if you're in the US, I'll mail you out one.