[sdiy] CEM VCOs (was Analysis of frequency variation in analoguesynths)

[harrybissell at copper.net]

"One man's meat is another man's poison..."

Which VCO is best depends on what you want to do with it.
If your patches make use of techniques like FM synthesis
(or similar) you will need the most stable VCOs imaginable...
so much so that almost ~every~ prectical system used DCO or direct
computer synthesis.

If you like 'lush' (read: beating) pads... a less accurate VCO
will be fine.

I think the CEM3340 is an excellent VCO overall. I had no problem
enjoying my Prophet V or ProOne. In fact I added 40 trims to the
Rev 3.2 P5 to allow the 'poly-mod' section to have consistant voicing.

Some might say this would reduce the analog goodness...

meat or poison ???  Eat up :^P

H^) harry
>
>---- Original Message ----
>From: tom at electricdruid.net
>To: nicksdsu at mac.com
>Subject: RE: [sdiy] CEM VCOs (was Analysis of frequency variation in
>analoguesynths)
>Date: Thu, 3 May 2007 20:59:33 +0100
>
>>>>
>>>> Does anyone have a strong feeling as to whether the CEM VCO has  
>>>> this analog warmth?
>>>
>>> I've owned a Roland SH-101 (single CEM3340) and Akai AX60 (6 voice
> 
>>> CEM3394 VCO/VCF/VCA chip) and concluded the CEM oscillators were  
>>> not as warm as other VCOs found in the SH-3a or Andromeda, or as  
>>> analog (but not necessarily warm) as an Odyssey VCO.
>>>
>>> On the other hand I played a MemoryMoog+ and thought it had a  
>>> fantastic sound, though I never brought it home for late night for
> 
>>> comparison to other gear.
>>>
>>> I am interested in other people's opinions of CEM VCOs.
>>
>>I have both a single CEM SH101 and a dual CEM Sequential Pro-One.  
>>Most of the SH101s character comes from the filter, which is really 
>
>>something else. The Pro-One manages to get a very big dense sound
>out  
>>of a pair of 3340s, although the filter thins it out. Definitely a  
>>lead synth, whereas the SH101 excels for fat squishy bass. For sonic
> 
>>comparison, I've got the completely different architecture of the  
>>Korg Polysix. The Polysix VCO is a fairly flat sound in my opinion  
>>(although I think the SSM2044 filter and analogue chorus more than  
>>make up for it).
>>
>>I haven't compared the circuit diagrams for the two CEM synth's  
>>oscillator sections, but I doubt either of them differ much from the
> 
>>datasheet.
>>
>>Overall, I like the CEM VCOs. I do think they have 'analogue  
>>character', whilst also being reasonable stable, especially after  
>>having warmed up. In that respect, I think they are a good  
>>compromise. I wouldn't want them to vary or drift any _more_ than  
>>they do already, let's put it like that...
>>
>>
>>
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