"Jim Thompson" wrote in
message ...
On Sun, 14 Jun 2009 19:39:09 +0100, "ian field"
wrote:


"Jim Thompson" wrote in
message ...
On Sun, 14 Jun 2009 17:18:58 +0100, "ian field"
wrote:


"Jim Thompson" wrote in
message ...
On Sun, 14 Jun 2009 16:08:47 +0100, "ian field"
wrote:

Does anyone know where I can find more info on the two transistor
feedback
pair (I think some people call it a "shunt series pair")?

Having spent much of Saturday googling I only found coincidental
mentions
of
the circuit in other articles - I had hoped to also find some info on
the
history of the development of the circuit.

Can anyone help?

TIA.


I've known of it since I was a kid. For an advanced version see
MC1552/1553 on my website.


Thanks - I should have indicated that I was interested in audio
applications.


The MC1552/1553 is classic for such an application. Change the purely
resistive feedback to RIAA or whatever you're in need of.

What I'm looking for is more along the lines of designing such a circuit
around discrete transistors and perhaps a little history on how/when the
circuit was developed.


When I was in high school (1955-1958) that configuration was already
in use in preamps. I even built one using Germanium transistors.

There's nothing magic about the circuit. Try analyzing it. If you
get bogged down, let me know.


If you mean with a circuit simulation programme, I don't have one.

The basic configuration and formulas would be handy if you have them.

I'm curious about the history because I think the circuit was developed to
get decent gain out of early low spec germanium transistors (by using 2 in a
single stage) without noise and distortion penalties. The circuit also
performs well with silicon and remained popular long after germanium fell
out of use.