[sdiy] ASM-1 type VCO freq. range

[Henri Kovalainen]

On Fri, 25 Jan 2002, Gene Stopp wrote:
> The VCO used in the ASM-1 (designed by Terry Michaels, originally published
> in Electronotes back in the 70's, built with modern parts today) is by far
> the widest range DIY VCO I've seen, which is why I picked it in the first
> place :)

Oh, yes. Though I have never seen the original design, I was aware of the
history. =)

> It will go from one cycle every few seconds to over 50 Khz in one
> CV sweep. The waveforms are preserved quite nicely all the way if you use
> fast op-amps. The TL-082 works fine at the very least to above 20 Khz.

Yes, that should be enough. I just want my VCOs to be capable of being
used as voltage controlled (and syncable, variable pulse width and so on)
LFOs. Also double audio (or so) rates would be nice to have, too, if you
have to say, play a lead using a sub octave divider or something.

Once I design a pcb for the VCOs with the proper wave shapers etc. I'll
just build plenty of those to take care of all my oscillation needs. =)

I have mostly used the TL07x series so far which should be fast enough
here. If you drive something at 40KHz, it'll probably be a divider and in
any case the wave shape won't really matter.

Sounds promising. Thanks everybody.

| henri kovalainen   | peltokatu 19 b51   | hekovala at kovalainen.fi
| phone: 0400-683750   90120 oulu finland   hekovala at paju.oulu.fi

| Practise economy at any cost.