[sdiy] VCLFO core circuit..

[David G Dixon]

> Instead of the ARP VCO, I might go with something like this:
> http://www.birthofasynth.com/Thomas_Henry/Pages/VCO-1.html
> 
> This VCO is based on the 3080 chip (still fairly easy to 
> find, or replace it with a 13700), has a linear FM input, and 
> uses two PNP transistors in the expo converter. This will be 
> a simple circuit to build, and will be more than adequate for 
> VCLFO use.

I concur.  Great little circuit, I've built a few of them.  They make great
VCOs as well.  I used unmatched 2N3906s for mine, and the tracking was
pretty decent.  Why not put a range switch to a second capacitor (say, 100x
larger) on the integrator (switch between integrator's inverting input and
cap, other end of cap hardwired to integrator's output) and make it a
VCO/LFO, especially if you're going to go to the trouble of putting in a
tempco resistor.  The only problem with using tricores as LFOs is that they
are difficult to hardsync, so perhaps less useful for percussive/bass
effects.