VCO hacks, tweaks

[terry michaels]

Message text written by INTERNET:ijfritz at earthlink.net
>Well, I just stumbled on that one. I started with a garden-variety FET
op amp there, but discovered by putting a finger on it that there was
quite a bit of temperature sensitivity. The better op amp helped quite a
bit. Maybe an opamp optimized for offset drift would be even better. I
like to keep the slew rate up here, though, in case I want to do some
high-frequency FM.  
<

Hi Ian:

You don't have to worry about slew rate here, because the voltage swing is
so small, just about any op-amp you can think of is more than fast enough. 
The OP07A is very slow, but it has a great offset voltage drift spec. There
are probably even better op amps out now (OP27 maybe?).

Terry