Maxim MDS-500

[WeAreAs1 at aol.com]

Hello Peter,

Those SSM2044's are most likely being used as normal filters, not as sine 
wave oscillators.  Most of the similarly-designed Simmons drum modules also 
have filter chips (some with SSM2044, some with various CEM chips).  The 
filters are there to put a filter envelope on the noise component of the 
sound, and also to act as a general tone control.  They may, however, not 
give the user access to the filter cutoff in every design.

Most of the Simmons modules create their basic drum tone waveform with a 
typical two-opamp triangle wave oscillator (such as the ones typically used 
to make simple LFO's).  The Simmons SDS5 used exactly this combination 
(SSM2044 filter with opamp triangle linear-response VCO).  I imagine that 
your Maxim unit uses the same technique, since they were probably trying to 
copy Simmons in the first place.  I suppose you could remove the 2044's and 
replace them with some other kind of filter, if you're up to the effort.

Michael Bacich