Doepfer

VC slope generator module!

great news for the A100!


Bakis Sirros - Parallel Worlds / Interconnected / Memory Geist

[Doepfer_a100] group owner

www. parallel - worlds - music. com

www. myspace. com/ parallelworldsmusic

www. myspace. com/ interconnectedmusic

www. myspace. com/ memorygeist

www. DiN. org. uk

www. musicamaximamagnetica. com

www. vu-us. com

--- On Wed, 6/30/10, yahoo@doepfer.de <yahoo@doepfer.de> wrote:

From: yahoo@doepfer.de <yahoo@doepfer.de>
Subject: AW: AW: [Doepfer_a100] DIY Doepfer Synth | first panel
To: Doepfer_a100@yahoogroups.com
Date: Wednesday, June 30, 2010, 5:32 PM







 



  


    
      
      
      Again: my comments are written inline.



Dieter



> That was the plan, yes.

> The VCA Am inputs  will be easy. For the Lin FM I'd probably have to try a

bit harder.



The serial resistor for the linear FM input is 100k (R11 leading from the

VCO lin FM input to the summing node for the linear FM). If you add e.g.

another 100k resistor the sensitivity is half as much as before.



> > > not very happy with the way the Slew Limiter works.

> > I'm surprised to hear that. The slew limiter works like all slew

limiters,

> > nothing but a capacitor buffered by an operational amplifier that is

charged

> > via a variable resistor (potentiometer with logarithmic scale in the

range

> > 1M...5M recommended). It's exactly the same curcuit as for the upper

unit of

> > the A-170.

>

> I used a 1M Audio. Might try a higher value...



You may even increase the value of the slew capacitor which is only 220nF

(C21 on the top right edge of the pcb). You may solder e.g. a electrolytic

capacitor (1u...10u) in parallel to C21 to increase the max. slew time. The

right pin of C21 is GND (i.e. the minus pole for an electrolytic capacitor)



> All the classics then... :-)

> I'd prefer more wave-shaping/multiplying over an additional

> oh-no-not-again! LP filter.

> And extended VCLFO, preferably with PW/M, would be very cool, yes.

> Some easy little stuff like Boolean logic, comparators & Schmitt

> Triggers would be welcome too.

> Or replace 70% of all of the above with one VC Slope generator :-)



Yes, we are working on a VC slope generator too (even as an A-100 module).

Maybe we could add it to the expansion board.





    
     

    
    


 



  






      

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