Moog Filter!

[Harry Bissell]

I'd like to see the micromoog/multimoog schematic... can someone point the way ???
Thanks. :^) Harry

Sean Costello wrote:

> Tony Allgood wrote:
> >
> > Rene >This also explains why the self oscillation stops below some
> > frequency.
> >
> > This is so true, but it doesn't explain why the new MiniMoog made in
> > Wales oscillates across the spectrum. The manufacturers say this is a
> > bonus feature, ie. better than the original.
>
> The new Wales Minimoog probably uses a different coupling scheme. Most Moog
> filters (such as the Prodigy, Rogue, and Tom G.'s scheme) have a different
> coupling scheme for the differential output amplifier, that produces a more
> constant Q throughout the audio range. However, I would not call having constant
> Q in the Minimoog filter a "bonus." As far as I understand things, the drop-off
> in Q in the bass register of the Minimoog filter contributes to the great bass
> sound of that synth. The same characteristic can be found in the TB-303 filter.
>
> As far as constant Q in a Moog filter, I would think that this would only be
> important when the filter is being used as an additional oscillator (such as in
> the Multimoog, where it is used as an FM source). For this to really be useful,
> the filter must be temperature compensated. The Micromoog/Multimoog had a nice
> way of doing this, where the filter expo convertor was on the same heated 3046
> chip as the expo convertor for the modulating oscillator.
>
> Sean Costello