ASM-1 vco range

[Tony Clark]

> Anyone know how to decrease the range of the VCO's on an 
> ASM-1? Mine has an extremely wide range. Haven't measured 
> the frequency range but the knob only turns about 1/3  
> before the frequency is above hearing range. I want to lower 
> the range on the pot so it only operates in the audio range.
> same is true on both VCO's. I used MAT-02 matched pairs and 
> all precision 1% resistors.

   Yep, it was a design "feature"!  If you want to just scale the pot, 
put a resistor on one leg equal to the pot's resistance.  That'll cut it 
down by half.  Can't tell you which way to wire it.
   Otherwise, one way to lower the range is to increase the integrator 
capacitor.  Doubling the size will do nicely.  Another way is to increase 
the current resistor on the MAT02 (I believe it's either 1 Meg or 1.5)  
Of course both of these won't help your "range" problem, but it will 
lower the upper frequency limit and probably give you some nicer low end 
range for LFO duty.

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------