Archive of the former Yahoo!Groups mailing list: MOTM

This is like asking 50 people about beer.

The #1 thing that people have determined is that the top and
bottom pairs in the ladder need their Vbe voltages matched
as close as possible. I am betting that Moog saved the "good stuff"
for the modular. The Minimoog had over 15,000 built, versus probably
500-750 Moog 904s. So, just as a matter of "cranking them out", the
matching (all done by hand with a 1970 voltmeter!) was sloppier
on the Minis.

Also, the #2 factor is the input impedance of the differential amplifier
that 'taps' the signals off the ladder. (BTW: if this sounds like babbling,
then head over to www.ibm.com/patents and download Moog's filter).

In the MOTM-400, #1 is solved by 2 pre-matched (actually, laser-trimmed to
∗be matched∗) transistors, and #2 in easily solved in today's world with FET
input op amps.

However, it's all subjective and I hope everyone will be happy with it.

Paul Schreiber