[sdiy] Replacing CA3080 with CA3046 ??

[Antti Huovilainen]

On Sun, 10 Apr 2005, karl dalen wrote:

>> Is it possible to take that into account and trim the input for minimum
>> worst case bleedthrough?
> Yes and no, it becomes a avarage trim then either you have
> to for hand go trough all 40 of your 13700 and match each and
> every one of them and as Ian says match even each dual pair!!

Actually now that I think through it again, I think I will be getting that 
for free based on the the trimming method. As the VCAs are controlled by 
MCU anyway, easiest way to trim would be to mute the previous circuitry 
and feed squarewave to VCA CV. Then just find the trim position where 
output signal is lowest.

>> How bad is the CV bleedthrough for untrimmed 13700 circuit?
> As said its varying, the BIT99 used the standard way of triming,
> one pot each VCA. BTW the designer of the BIT99 was the same

Can you give some numbers? 2x? 10x?

> Are you building a vocoder Antti?

Worse: Polysynth :) (at design stage still)

Antti

"No boom today. Boom tomorrow. There's always a boom tomorrow"
   -- Lt. Cmdr. Ivanova