[sdiy] Polymoog resonator question

David G Dixon dixon at mail.ubc.ca
Sat Oct 6 07:30:19 CEST 2018


Why, do you want to invest?

As I said before (and I suspect you are only asking this to piss me off...
mission accomplished!) I don't believe that the question is a) relevant to
this list, or b) any of your damn business.

However, I am going to answer your question.  If I build one and I think it
is fantastic, then yeah, I'll probably try to sell a few.  I very strongly
doubt that Danjel at Intellijel will be the slightest bit interested in this
design (too simplistic, too esoteric, not digital enough), so the sales will
probably be limited to handmade PCBs (they take me an hour to make, and I
charge about $20 for them -- I might sell a total of ten) and maybe a few
handmade modules (I would be surprised if I ended up selling more than two
or three, and I earn well less than minimum wage for making them).

So, if it gives you the willies to think that you might be helping me make
almost enough money to cover my cost of parts on this project, then please,
please don't compromise your precious ethics by answering any of my
questions.



> > -----Original Message-----
> > From: Ian Fritz [mailto:ijfritz at comcast.net]
> > Sent: Friday, October 05, 2018 12:21 PM
> > To: David G Dixon
> > Cc: Donald Tillman; synth-diy at synth-diy.org
> > Subject: Re: [sdiy] Polymoog resonator question
> > 
> > Will this be a commercial product?
> > 
> > > On Oct 5, 2018, at 12:54 PM, David G Dixon
> > <dixon at mail.ubc.ca> wrote:
> > > 
> > > Thanks, Don.  That's what I figured.  I have removed CD4000
> > switches
> > > from many designs and replaced them with DG400 switches for
> > that very reason.
> > > 
> > > I'm going to redesign this Polymoog Resonator, using 
> 2164s for the 
> > > R's, putting the stages under voltage control, and changing
> > the output
> > > switching situation a fair bit.  I'm still not sure what
> > I'm going to
> > > do about the loop gain situation.  I'm deriving the
> > transfer function
> > > right now to get a better idea of what it actually does.
> > > 
> > > 
> > > 
> > >> -----Original Message-----
> > >> From: Donald Tillman [mailto:don at till.com]
> > >> Sent: Thursday, October 04, 2018 11:04 PM
> > >> To: David G Dixon
> > >> Cc: synth-diy at synth-diy.org
> > >> Subject: Re: [sdiy] Polymoog resonator question
> > >> 
> > >> 
> > >>> On Oct 4, 2018, at 9:57 PM, David G Dixon
> > <dixon at mail.ubc.ca> wrote:
> > >>> 
> > >>> I did have one other question, though...
> > >>> 
> > >>> What is the significance of "V_CH" which seems to play the
> > >> role of ground almost everywhere in the schematic?  Is this some 
> > >> specific voltage which is not 0V?
> > >> 
> > >> Indeed, V_CH is 4.85 V.
> > >> 
> > >> That audio section uses CMOS CD4000 series chips for audio
> > switching.  
> > >> Those max at 18V.  So the Polymoog runs the CMOS at 0 to 
> +15V, and 
> > >> biases the audio signals up a little to fit in there.
> > >> 
> > >> The alternative would be to leave the audio centered
> > around 0V, and
> > >> run the CMOS at something like +/- 5V.  Then all the logic lines 
> > >> would have to be shifted.  Which is a drag, but would have been 
> > >> better for audio quality.
> > >> 
> > >>  -- Don
> > >> --
> > >> Donald Tillman, Palo Alto, California http://www.till.com
> > > 
> > > _______________________________________________
> > > Synth-diy mailing list
> > > Synth-diy at synth-diy.org
> > > http://synth-diy.org/mailman/listinfo/synth-diy
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy



More information about the Synth-diy mailing list