[sdiy] Later MS-20 filter with 2164

[Walker Shurlds]

Aren't there two different MS-20 filters?  One with the Korg-35 chip
and one with the LM13600 OTA?  Are yall talking about different ones?

Walker

On Thu, 1 Jul 2010 14:28:02 +0300 (EEST)
Antti Huovilainen <ajhuovil at cc.hut.fi> wrote:

> On Wed, 30 Jun 2010, David G. Dixon wrote:
> 
> > I'm not really following you here, as there are no emitter
> > followers in the schematic I'm working off of (unless you are
> > talking about the situation inside the OTAs themselves).
> 
> http://www.synthdiy.com/files/2003/KLM-307.gif
> 
> The emitter followers I'm referring to are the buffer stages of the 
> LM13600 (pins 10/9 and 7/8 in that schematic), which are simple two
> stage emitter followers with the first stage having a current sink
> load (with the current scaled by Ictrl in LM13600 and fixed in
> LM13700).
> 
> >> The two transistor (Q3 & Q4 in my copy of klm-307.gif) discrete
> >> VCA is likely to affect the sound, so you'd need to tap the output
> >> of the LPF directly for a valid comparison.
> > I haven't used any discrete transistors; only 2164s.  And, as
> > mentioned above, I will not be reproducing the output circuitry of
> > KLM-307.
> 
> That's what I assumed. I meant that the reference MS-20 should have
> the output tapped directly from filter output instead of regular
> audio out (as MS-20 seems to lack filter output jack).
> 
> Antti
> 
> "No boom today. Boom tomorrow. There's always a boom tomorrow"
>    -- Lt. Cmdr. Ivanova
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