[sdiy] Polymoog Resonator - no-pots equivalent

sleepy_dog at gmx.de sleepy_dog at gmx.de
Wed Aug 23 20:07:23 CEST 2017


David G Dixon wrote:

 > Every time I put in a Small Bear order, I order about 25 of them

that's funny, I do that with the 13700 anywhere I order something and 
they have a good price (like 85 ct / piece @ 10), but it's just 10 every 
time ;-)


> 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
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>




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