Ok so i got some trimmers and for some reason im getting a lower level rush of white noise on the vca's output every time the cv level goes low, no matter what i do i can't trim it out.I pulled the 5k trimmer (cv reject) and that got rid of it but i lose a lot of gain on the output of the vca.
Anybody have any suggestions ?
Thanks, Tony
Anybody have any suggestions ?
Thanks, Tony
--- In cgs_synth@yahoogroups.com, "adematteo" <adematteo@...> wrote:
>
> Thanks Ken, I just wired up the vca and it sounds good to me.
>
> I didn't match the bc548's so maybe i got lucky.
>
> I did match the dual npn's using the HFE test function.
>
> I don't have any trimmers yet so i'm hearing the thump of dc coming through but other than that the source signal sounded good.
>
> Thanks for all your help !
> -Tony
>
> --- In cgs_synth@yahoogroups.com, sasami@ wrote:
> >
> > >That's good to know Ken !
> > >Do you recommend using the HFE to match the transistors in your vco instead
> > of the lm394 ?
> > >I'm not concerned about 1v/o tracking being super accurate.
> >
> > If you aren't worried about accuracy, sure, that would do the trick.
> > Separate transistors will never be as good as a dual, due to the thermal lag
> > caused by the separation of the transistor dies in their own little epoxy
> > packages.
> >
> > >Also, how do you "join" the 2 transistors together ?
> >
> > A wire tie around them, with them flat to flat will do the trick. Some
> > people go as far as epoxying them together.
> >
> >
> > Ken
> > _______________________________________________________________________
> > Ken Stone sasami@ otherunicorn@
> > Modular Synth PCBs for sale <http://www.cgs.synth.net/>
> > Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
> >
>