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