AW: Minimoog Vcf

[Haible Juergen]

	>> Well,I found that R20 resistor from Q6 emitter to -10 is 100k not
220k
	>> And +10V should go not to col. of Q6 but to other side 
	>> of R6 47ohm resistor and + node of C9 100uF ? 
	>> Not shure about that last but if you look at moogmodular vcf, it 
	>> looks like that.
	>> 
	>This makes sense. It is a kind of emitter follower (darlington).
	>In this case the emitter resistors should be equal.
	>And it is a differential to single ended converter. Again symmetry
	>is required.
	>
	>Can any of the moog godnesses confirm ?

Well, I'm not from the Moog Olymp, but I have built my MidiMini
from the original Minimoog schemos (the VCF part, that is),
and it works.
There is good reason the R6, C9 filter for the left side of the
differential amp, because the filter output signal is related to the
positive supply, and not to GND. The right part of the differential
amp has no output, so connecting it directly to the dirty +10V
is ok. Therefore I think the schemos are right.

Just my opinion - never looked into a real Minimoog.

JH.