Does a BA6110 really need an output buffer when a VCA?

Ricko

I bought some BA6110 VCAs to use them for utility VCAs.

There are some circuits floating around, like the Curetronics one which is based on Roland designs. So i am looking to see what the least component version of a vca module might be.

But I have been wondering, does the 6110 really need to have any output buffering (trannie, op-amp, whatever) when used as a simple VCA?

When used in VCFs, the similar BA662 has FET buffers between the stages. But when used an 80017A package for things like the Juno 106, all the voices are just fed into an active mixer. So what value would an extra output buffer be?

Here is the data sheet with VCA circuit
http://urekarm.tripod.com/synth/BA6110.pdf

And some extra info on 80017A
http://obsoletetechnology.wordpress.com/projects/80017a-vcfvca-teardown/

bod · Joined: Apr 28, 2009 Posts: 148 Location: Glasgow

i've been using the ba6110 in my analogue dub sirens, and rightly or wrongly i haven't been buffering the output with an opamp or anything. the final stage of the ic is a buffer anyway.

i have a pot on the output for volume output control and a capacitor after that, but i havent found any issues with it so far. theres not much to it really, i think i have 4 or 5 resistors and a couple of caps in my vca. i'll post a schematic if you want/need one.

cheers,

bod.