[sdiy] Polymoog Resonator - no-pots equivalent

[David G Dixon]

Hey sleepy_dog,

You can buy the V2164 from Small Bear or Mammoth for less than $4 per.
Closer to $3 per in quantities.  Every time I put in a Small Bear order, I
order about 25 of them.  For me, they're like Frank's Red Hot: I put that
shit on everything!

Dave Dixon (Doc Sketchy)


> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On 
> Behalf Of sleepy_dog at gmx.de
> Sent: Tuesday, August 22, 2017 11:52 AM
> To: synth-diy at synth-diy.org
> Subject: Re: [sdiy] Polymoog Resonator - no-pots equivalent
> 
> 
> 
>  > No, the CoolAudio V2164 is widely available and cheap - 
> and in both DIP and SMD
> 
> *V*2164, eh?
> http://m.memegen.com/ub1ae4.jpg
> 
> I will at least put the existence of those into the back of my head.
> One  needs to get them at 3rd party distributors instead 
> directly, eh? 9 bucks at small numbers otherwise... plus 
> probably not so nice shipping costs to my country.
> But if this thing has 4 complete VCAs and only minimal (?) 
> support circuitry, it sounds like a nice IC.
> 
> Do they perform significantly better than LM13700 based VCAs 
> (and as VCFs, too) with similar parts count?
> And if so - does it matter for this particular project?
> 
> What's even cheaper than cheaply sourced parts is using stock 
> you already have.
> And I have roughly one kilogram* prime LM13700 at home. Might 
> as well use them :-D
> 
> * slightly exaggerated. May be 150g.
> 
> 
> Steve
> 
> 
> > No, the CoolAudio V2164 is widely available and cheap - and 
> in both DIP and SMD. The original Analog Devices SSM2164 
> might cost silly money by now, but it's the same thing.
> >
> > Tom
> >
> > ==================
> >         Electric Druid
> > Synth & Stompbox DIY
> > ==================
> >
> >> On 21 Aug 2017, at 20:16, sleepy_dog at gmx.de wrote:
> >>
> >>
> >> Thanks Tom, yes that cleared some things up. "go wild with this", 
> >> yeah, I have some ideas about that ;) The 2164 being one 
> of those ICs available for collector's prices? Although I 
> might even have some of those hidden in some box... But I 
> think I'm going to make this SMT.
> >>
> >> Am 21.08.2017 um 19:46 schrieb Tom Wiltshire:
> >>> Hi Steve,
> >>>
> >>> Yes, three multimode filters would be the same as the 
> PolyMoog resonator. That's what it is:
> >>>
> >>> http://www.synthfool.com/docs/Moog/polymoogresonator.jpg
> >>>
> >>> Note that the schematic shows us that the filters are 
> state-variable filters (which we'd guessed anyway because of 
> the HP, BP, and LP outputs) and that they're *not* VCFs. 
> They're just based on op-amps. You also mention the slopes. A 
> 12dB SVF has 6dB slopes for the BP output. That's normal, 
> since that's a 2-pole bandpass filter, and it's a 2-pole 
> filter. The way I think about it is that you need to filter 
> off both the low and the high frequencies, so you have to 
> share the poles out to do the job!
> >>>
> >>> The Moog schematic is about as simple as such a thing 
> could get, since it is pretty much just the three SVFs joined 
> together. Personally I don't like the way you have to change 
> the response of all the filters together instead of 
> individually, but that would be easy to change. Compare with 
> this schematic:
> >>>
> >>> http://sound.whsites.net/articles/st-var-f1.gif
> >>>
> >>>
> >>> Obviously you could go wild with this. Some years ago I 
> built SVF+VCA modules around the 2164. This would be perfect 
> for this, since you get a 2-pole VCF with VC resonance and a 
> VCA all on the one chip.
> >>>
> >>> http://electricdruid.net/images/svf+vca.jpg
> >>>
> >>> I don't seem to have the schematic online, but ask me if 
> you're interested.
> >>>
> >>> HTH,
> >>> Tom
> >>>
> >>> ==================
> >>>         Electric Druid
> >>> Synth & Stompbox DIY
> >>> ==================
> >>>
> >>>> On 21 Aug 2017, at 17:16, Steve <sleepy_dog at gmx.de> wrote:
> >>>>
> >>>> Hey experienced SDIYers,
> >>>>
> >>>> say, would slapping together 3 {VCA, multi-mode VCF 12 
> dB/oct with 
> >>>> Q control} combos be the functional equivalent of the 
> Moog Resonator? (with modified VCF control ranges, limited to 
> 1 of those 3 bands each) Although I faintly remember some of 
> those multi mode VCFs having only 6 dB/oct slope on BP. Maybe 
> not those. Are there designs with the same slope for all, or 
> is this a general feature of such VCFs?
> >>>>   My goal is to make something that can shape sounds 
> similarly to the Moog thing, as demo'ed on YT by some guy 
> enhancing vocal and brass sounds.
> >>>> https://www.youtube.com/watch?v=_XUiJi5153Y
> >>>>
> >>>> But in a much smaller box, without the battalion of pots.
> >>>>
> >>>> I thought about just taking J.Haible's schematic and 
> replacing all 
> >>>> the pots with MCP41HV digipots, but that'd be 14 (some 
> are stereo), 
> >>>> a bit expensive *and* wiper noise, that doesn't taste 
> well together 
> >>>> ;)
> >>>>
> >>>>
> >>>> - Steve
> >>>> _______________________________________________
> >>>> Synth-diy mailing list
> >>>> Synth-diy at synth-diy.org
> >>>> http://synth-diy.org/mailman/listinfo/synth-diy
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