VCOs as modulation sources

[Christopher List]

>      in high school in 1976, is the *best* FM thing I've ever played 
>      with!!! The potential modulation depths are about twice as deep on 
>     that machine than on any other commercial system I've got.
     
>     much conversation about it and I think that it's mostly unexplored 
>     territory because mod depths on commercial machines just don't reach 
>     far enough. I'm dying to dive into it again.

Funny you should mention this. 
One thing I noticed last night, just looking at the 0-scope, was that when 
modulating the audio with the timbre modulator I got a huge depth of 
modulation, but when I use the FM inputs on the EN tri-square VCO, the maximum 
depth is pretty small. 

I wonder why they chose 560K input resistor for the FM (?) to the voltage 
reference op-amp. I mean, it's connected to a depth pot... 

I think I will be trying lower resistor values this weekend to see if I get 
stronger FM. 
That won't screw up the MAT-03 pair will it?

- Chris