[sdiy] Small signal transistors

[David Ingebretsen]

Back to the Steiner Synthasystem project. 

I have a question about substituting small signal transistors in the
exponential converter section.

Nyle used 2N5172s and a 2N5138 PNP in his version. Can I substitute a
SSM2210, or LS318, or even a THAT340 without changing the biasing resistors?


The THAT part has the advantage of having two matched NPNs and two matched
PNPs on the same substrate. Nyle noted, in his design he wanted the two NPNs
and the PNP to be in thermal contact with the thermistor, I thought the THAT
part would be a great way to get them as close to the same temp as possible.

The pinout on the THAT340 DIP part is also such that you could just use an
SSM2210 or LS318 and a discrete PNP and still have them right together. I
could even hand match some NPNs and do it that way.

Mostly, I'm curious about the biasing resistors and other components and
whether I need to change anything.

David