qs to Mark and other gurus...

[swt]

First of all i have to thank you guys for responding all my qs so nicely, i've been learning a lot at your expenses ( there's a lot of time in doing so).
I want to have a good ring mod. I have the datasheet for the mc 1496. It's just made with a few transistor arrangement. Do you think it's possible to get a clone of this ic made with transistors?. What is the target to do so?. Matched trannies?. Any other spec?. Am i so crazy?. Thanks a lot for your replies/opinions.

[R.G.]

The 1496 costs under $1. Why not just use one of those?

However, in answer to your question, yes, you can make a fake 1496 from two transistor arrays. Any of the five-NPN arrays can be interconnected to do a similar function. All four of the cross coupled upper differential cells should be in one array, the lower five in the other.

[swt]

Thanx R.G.!! Where do you get those ics from?

[R.G.]

I realize that if you're really in Patagonia this is going to be hard.

The MC1496 is also available as the LM1496, same part, different manufacturer. I put in "MC1496 price*" in google and got 80 hits, mostly from parts sellers. "LM1496 price*" got quite a few more. They're not as common as opamps, but not at all rare.

The real problem with making your own out of transistors is that the diffamps really do matter if they're not matched. That's why I suggested the transistor arrays. You can hand match transistors, but there are a lot to do here, and finding a quad matched is a bear.

[swt]

I'll try the transistor arrange only as a last chance. Will try to get them any way i can. Is it true that there's no carrier feedthrough with this ics??. Thanks a lot RG!!

[puretube]

there`ll always be a little feedthrough;
with a welldesigned 1496 circuit you can null it out (use multi-turn trimpots) to about -60dB (i.i.r.c.)

[Mark Hammer]

http://members.tripod.com/urekarm/synth/vcs3_rm.pdf

http://members.tripod.com/urekarm/synth/serge_rm.pdf

http://members.tripod.com/urekarm/synth/download.html

[swt]

Thanks to you guys!!. i've ordered the ic and hope to get it in here.
Mark?. ...can you tell me how to put that sample and hold circuit in a filter, and lfo?. Thanks!. That looks easy and really cool.