CA3080E

[Transmogrifox]

thanks again.  I've been tweaking around, and have not yet successfully diminished the low-level feed-through.  At least I got rid of the distortion.

I think I will be making a PWM VCA attempt here to see if I can make a volume swell based on that.  I'll post a schematic if it works.

[puretube]

free information block:

[Transmogrifox]

That seems like a promising approach.  I just posted in a new thread:  the PWM circuit was exactly what I was looking for.  It works beautifully with an LM339 if I keep the oscillator Frequency down at 22 kHz.  Wonderful resistance range, and perfectly dead extinction at minimum.  I think this will make a good base for the string swell effect.

[puretube]

free information block:

[zachary vex]

I hate to mention this, but a working OTA can be made from ten transistors and no other parts. Only one matched pair is strictly needed, but a four pairs makes it all dandy.

There are no passive parts in an OTA except conductor metalization.

Shoot, maybe I should whip up an all-transistor OTA replacement board for the CA3080. I suspect that with surface mounts, it might be not much larger than the 3080.

But Mark's right - look for LM3080.

show us.  we may need that knowledge evenutally.  8^)

[puretube]

free information block:

[MartyMart]

Well the shortage hasn't hit yet, "RS components" UK has them for less than £1 each and Olaf at "BanzaiEffects" has CA3080E's for 0.54 euro's each !!

Just my 2c worth.
BTW: That 1974 article is great information, thanks puretube

Marty.