13 Dollars for an electronic switch ?? (was: 4066's. Eat em up, Yum)

[The Dark force of dance]

Y-ellow Juergen.
        Thanks for that interesting insight. And whilst I think of it I
guess I should really get on the DIY list again. When I get my noo mail
stuff set up fur sure.

I wouldn't use a 3080 if I could possible help it but I have been known to
use bucket loads of 13600s. I know there's not a real lot of difference but
I use to get them cheaper than a 3080 so it makes economic sense. What I
could get them for now is anyone's guess.

I did find though, that under the same conditions, the 13600 was quieter.
I've used them in multiplexing applications before but never set up as with
feedback. The requirements in this case was a smooth transition, a seigue if
you will, between channels. Actually the circuit is on my web page in the
time related multi FX processor circuit.

That aside it's a damn good idea. And one worth investigating. Though I
would still need at least 8 OTAs per channel. That's 40 13600 packages. If
4066s or DG201s were practical, I'd only need 20 packages. Remember that's
10 stereo channels in across 4 stereo busses out.

If I were to use OTAs I'd be real tempted to arrange it to fade in and out.
Integrate the control signal over a cap and slow it right down. That would
be so silky smooth. No thumps and very sexy. But I'm not sure that it would
work within a feedback network. I know I've had OTAs with feedback for some
reason but I can't recall what or why. 

Y'a know it occurs to me that there's probably chips out there to do all
this stuff. Probably an analogue cross point switch. Probably 10 in and 4
out. Made of fets with it's own latching and able to run on 30 volt
supplies. Probably! Actually I saw the data sheet for something close the
other day. And of course Harris make a lot of this stuff. If you're into 5
volt single supplies.

In fact the chip I'd be real interested in investigating is the SSM2163.
This little puppy is a complete, digitally controlled, 2 bus, 8 channel
mixer. 2 of 'em together makes a stereo 8 channel mixer with 2 stereo
busses. I don't know how much they are. Nor where to get 'em but they look
pretty interesting on paper. But then again it's not quite what's required
in this app.

There's a FAB called quality-semiconductor who make a series of multi
channel change and change-over FET bases switchers and muxes. Once again not
quite what I'm looking for but interesting none the less. And it's a shame
about the Harris ones being only 5 volt. Otherwise you could build a
digitally controlled pin-block like the VCS3 has. Only without the pins of
course. Would make an interesting patch bay.

But anyway OTAs would most certainly overcome any crosstalk ambiguity. 

Ooo Ooo. And another chip I just thought of. Once again on the expensive
side but these guys are better than OTAs. It's a little 8 pin VCA chip from
Motorola. Now what's it called? Let me look it up here. MC3340 that's the
one. Only the VCA stands for Voltage Controlled _Attenuator_. Rather than
Amplifier. You only get one per package but because they're an attenuator
rather than an amplifier they're real quiet. I've got 3 of 'em somewhere.
Back in the days when you could get them. I use to have 4 but I used one.
Only I can't for the life of me remember what I used it in. But anyway
they're pretty groovy

Anyway thanks for that Juergen. It's another good idea to experiment with.
even if I end up using a combination of these ideas.

I'll keep researching.

Be absolutely ICebox.
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