Amateurs are most welcome. ;-)
I will probably be adding one or more of Harry's LAGs to my SteamSynth project very soon.
I looked over the circuit and realized that 4.7uf (4M7???) is a VERY large mylar cap. I doubt it is easily available, if at all. This MUST be a non-polarized cap. The Tant cap is VERY polarized so do NOT use it.
Now I have no direct experience with this circuit, but I see that it is in a closed loop feedback circuit, I would suggest that the 4M7 (4.7uf) cap would most easily be replaced with two 10uf caps in series, but wired "back-to-back" - meaning the two positives are wired together and then the negative leads inserted where the plans call for the cap. Does that make sense? I hope so.
Doug
I will probably be adding one or more of Harry's LAGs to my SteamSynth project very soon.
I looked over the circuit and realized that 4.7uf (4M7???) is a VERY large mylar cap. I doubt it is easily available, if at all. This MUST be a non-polarized cap. The Tant cap is VERY polarized so do NOT use it.
Now I have no direct experience with this circuit, but I see that it is in a closed loop feedback circuit, I would suggest that the 4M7 (4.7uf) cap would most easily be replaced with two 10uf caps in series, but wired "back-to-back" - meaning the two positives are wired together and then the negative leads inserted where the plans call for the cap. Does that make sense? I hope so.
Doug
--- In cgs_synth@yahoogroups.com, "Guy" <guy@...> wrote:
>
>
> Here's the amateur of the group (the one with the now-fixed LFO)...
> Tantaliums are indeed polarized. Long lead is +. I don't think you can replace a mylar with a tant.
> Don't tell Ken tho, he dislikes tantaliums. ;-)
>
> _g
>
>
> --- In cgs_synth@yahoogroups.com, "dumpstatic" <oozitron@> wrote:
> >
> > I can't find my docs for the Lag PCBs I have, but I have Harry's circuit diagram for help. I powered it up last night and it did some really strange stuff. Looking at the backside, I realized there should be some decoupling caps on the back... oops...
> >
> > Question #1 - would the absence of those 4 decoupling caps cause the 10uF electrolytic caps to get quite hot?
> >
> > Question #2 - I have a 4.7uF Tant cap where a mylar is suggested. Are Tant caps polarized? (one lead is longer than the other, but there are no +/- labels) Should a Tant cap work OK here?
> >
> > thanks a bunch for any help,
> > Drew
> >
>