Thanks for your help, Ken--I appreciate it. The capacitor was the problem. I
foolishly substituted a 4n7 for the 5n6, thinking that it would be close
enough. My bad! I put a 1n in parallel and the Grinder works much better
now. It produces a much wider and more interesting range of timbres.
Overall it's a very cool module, BTW. I set it up in a 3U panel in my
mostly-MOTM system, with all three modules (multiplier, simple folder, and
grinder) available on separate jacks.
--Adam
foolishly substituted a 4n7 for the 5n6, thinking that it would be close
enough. My bad! I put a 1n in parallel and the Grinder works much better
now. It produces a much wider and more interesting range of timbres.
Overall it's a very cool module, BTW. I set it up in a 3U panel in my
mostly-MOTM system, with all three modules (multiplier, simple folder, and
grinder) available on separate jacks.
--Adam
> -----Original Message-----
> From: sasami@... [mailto:sasami@...]
> Sent: Saturday, October 01, 2005 5:11 PM
> To: cgs_synth@yahoogroups.com
> Subject: RE: [cgs_synth] Finally! The Wave Multiplier is built.
>
> See the small "ringing" at the bottom of the lower "square" wave? You
> should
> be seeing that at about 5-10 times the amplitude on both the top and
> bottom
> excursions from a squarewave input. You are seeing ringing, but it appears
> to be happening across the whole signal. Do you have the correct capacitor
> in the feedback loop?
>
> Ken
>
> >I still don't fully understand what I should expect from this module. I
> >listened to the sample file in the yahoo group archive, and since I don't
> >know what the original signal was, I can't glean much insight.
> >
> >Since you said that an oscilloscope can help choosing an op-amp that does
> >the right thing, here's a screen shot of a square wave run through my
> >Grinder section, with both controls set to their middle position:
> >http://studionebula.com/images/CGS-WM-graph.jpg
> >
> >Here's an audio file of its output, same square-wave input:
> >http://studionebula.com/sounds/modular/CGS_WM_test.mp3
> >In this file I start with both controls rotated fully CCW. I turn one all
> >the way up and then all the way back down, then the other all the way up
> and
> >all the way back down, then one up to its middle position and leave it
> >there, then turn the other up to its middle position. If you can't tell
> >which knob is which, then you're understanding my point. :-)
> >
> >Thanks in advance to any other Wave Multiplier owners who can take a
> >look/listen to these files and tell me whether or not mine seems to be
> >operating properly.
> >
> >--Adam
> >
> >> -----Original Message-----
> >> From: sasami@... [mailto:sasami@...]
> >> Sent: Sunday, September 25, 2005 3:58 PM
> >> To: cgs_synth@yahoogroups.com
> >> Subject: RE: [cgs_synth] Finally! The Wave Multiplier is built.
> >>
> >> Basically the grinder is exploiting exactly what you DON'T want in a
> >> typical
> >> servo system (such as the feedback of an op-amp. It causes the op-amp
> to
> >> overcompensate, then overcompensate in the reverse direction etc,
> >> effectively causing a high pitch ringing on the output wave. If you
> have
> >> an
> >> oscilliscope, it can help choosing a chip.
> >>
> >> Ken
> >>
> >>
> >> >I am also happy with my recently completed Wave Multiplier, although I
> am
> >> >somewhat non-plussed by the Grinder section. It seems that its two
> >> controls
> >> >have basically the same effect on the timbre, although with slightly
> >> >different ranges of operation and some interdependence. It also sounds
> >> more
> >> >like a resonant filter than something I'd describe as a "grinder". Do
> >> other
> >> >Wave Multiplier owners observe similar behavior in their grinders, or
> is
> >> >there something wrong with mine?
> >> >
> >> >--Adam
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >> >
> >> >Yahoo! Groups Links
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> _______________________________________________________________________
> >> Ken Stone sasami@... or sasami@...
> >> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> >> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
> >>
> >>
> >>
> >>
> >> The CGS Modular Synth home page: http://www.cgs.synth.net/
> >>
> >> Yahoo! Groups Links
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> >
> >
> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> _______________________________________________________________________
> Ken Stone sasami@... or sasami@...
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>
>
>
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
