[sdiy] what opamp for "warmth"? (I know, I know...)

[Tom Wiltshire]

For synth pads, the envelope would be much slower, so the control feedthrough wouldn't be so obvious. I'm not saying it wouldn't *exist* but a slow rise of 100msecs+ in DC level is a lot easier to get away with than a sharp hit!

Tom

> On 7 Apr 2023, at 19:24, brianw <brianw at audiobanshee.com> wrote:
> 
> Speaking of control feedthrough, there was a paper written about modeling the TR-808 where it was mentioned that the "pop" or "click" from the CV was beneficial for percussive sounds. That wouldn't be so good for synth pads!
> 
> Brian
> 
> 
> On Apr 7, 2023, at 4:51 AM, René Schmitz <synth at schmitzbits.de> wrote:
>> You'll find the same VCA in the 909 in a few places. (Bassdrum , Toms, Clap..)
>> 
>> Note how far the signal is divided down. 
>> 
>> It's noisy, and nonlinear, and has some control feedthrough. Show what you can get away with for a single monophonic signal. 
>> 
>> The MS10 had the single transistor, the early "Korg35" MS20 had the same. 
>> The later MS20 had a second transistor, which makes things more linear/symmetrical and you can run larger amplitudes -> less noise. 
>> 
>> According to the schematics the transistors shall be selected. jx3p also says "SEL". 
>> 
>> Anyone would know what for? Equal gain? 
>> 
>> 
>> Best,
>> René
>> 
>> On 07.04.2023 11:04, Adam (synthDIY) wrote:
>>> 
>>> David G Dixon via Synth-diy pisze:
>>>>>>> Whatever the VCA is in the Korg MS-20 really warms up the sound of that synthesizer.  You can find the schematic on the internet.  I have something redrawn by a fellow named Marjan Urekar that I looked at years ago.  It involves two transistors.  It is evidently also the VCA used in the Roland JX-3P.
>>> 
>>> 
>>> Interesting.... here's the JX3P version
>>> 
>>> <grab 2023-04-07 at 6.57.54 pm.png>
> 
> 
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