Latest on MS20 Filter

[Keith Winstanley]

Well all is working well now although I spent a frantic couple of hours 
wondering why one of the filters suddenly stopped responding. It appears that I 
got some flux residue inside the freq cutoff pot while washing the flux off the 
board! DOH!

I have replaced the 47K resistors attached to the emitter of the 3906 with a 22k -

on Toms advice and have had to increase the 47K resistors associated with all CV -

inputs (including the cutoff freq pot) with 470K resistors to give me a workable -

frequency range on the filters. Maybe this is to do with the fact I am running 
off +/-12V?

There is only one problem..

The CV inputs have an inverted response with regards to my Analogue Systems 
modules. ie I have to invert the envelopes and if I put in a slope LFO I get a 
sawtooth response!

Oh well, I can live with that, unless someone knows a quick cure?

After all that I have a couple of great sounding LP/HP filters to play with.
Just need to do the front panel graphics now, I will put details of the filter 
project on my website as soon as I get the chance, along with some pics.
Many thanks too all who kindly offered advise, a great mailing list with a lot 
of great people on it!


...NEXT!

Keith Winstanley
http://dspace.dial.pipex.com/town/street/sl67/