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

Roman Sowa modular at go2.pl
Fri Apr 7 15:39:36 CEST 2023


The transistor is controlled purely with base current, so I'd say they 
were selected for beta to provide similar amplitudes after VCAs between 
voicces.
In my experiments I played with base resistor to achieve needed gain at 
fully open VCA

Roman

W dniu 2023-04-07 o 13:51, René Schmitz pisze:
> 
> 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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> 
> 
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