MOTM

For the CS-15: the same basic filter circuit is used here as in the 
CS-80, but there is only one filter per "channel" that is switch 
selected to be HP, BP or LP instead of the 80's hardwired HP->LP pairing.  
Like the CS-80, the CS-15 has two voice channels, just one pair instead of 
eight.  There are some other differences in the EG routing, too.

  For the CS-30 the filters are very similar to the way they're 
implemented in the CS-15.  The main difference in the CS-30 (vs. the 
CS-15) are that the filter EG is back (3 EGs total) and a sequencer is 
also installed.  The key filter difference is that the filters can be 
patched in series.

  An MOTM-480 is two 12dB/octave filters with HP/BP/LP simultaneously 
available internally, and with a spare 1U module panel and several 1/4" 
jacks the remaining ones could be brought out.

  480 is like this:

               +---> BP out
               | 
         (HPF) | (LPF)   (HPF)    LPF
   inputs--+---+---+   /---+---+---+---> LP out
           |  BPF      |     (BPF)
           |           |
           +-----------/

          (filter #1)     (filter #2)


  The "BP out" isn't on a CS-80 voice, it was added because there was
panel space and it is a useful signal.  However, it is simple enough to
bring the four remaining (HPF#1)(LPF#1)(HPF#2)(BPF#2) signals out to
jacks, and it is also (relatively) easy to use a switched jack to break
the filter#1->filter#2 path for both audio in and CV in, creating two 
completely independent filters.

Crow
/**/

On Thu, 16 Dec 2004, rreprobate wrote:

> I recently engineered a record for a band that used LOTS of cs-30 and
> cs-15. The filters were very different from the cs-80, which I play
> frequently.
> 
> I don't know the topology, but they are more resonant and moog-like.
> They are "lesser" in size, but I found them quite capable.
> 
> The motm-480 is a very accurate reinvention of the cs-80 filter, but is
> also capable of a much wider spectrum of sounds due to its modular
> format.
> 
> Max