vcf5t update (EWB data)

tomg efm3 at mediaone.net
Mon Mar 6 09:32:15 CET 2000


I've been out all day, so I missed most of this..I'll go have a look.

> Hi everybody...
>
> I modeled the VCF5T this afternoon.  It looks promising but the Bode plots
show a
> limited range of cutoff frequency... maybe 2.5Khz corner for values shown.
I think
> the
> control "phase splitter" is the problem... I think that ultimately the
cutoff is
> limited by the 100K resistors...

It has other problems too...;-) See my last post.

> If you use the dual expo converter proposed by messrs. Juergen and Osama
lately I
> bet this would perform a lot better... but it would take more trannies.
This
> would become a current fed diode bridge as proposed by Mr. Osama.

That was the whole point. It's 3 friggin transistors...hehehe

> I'll dink around a little more later...
>
> BTW Tom... bode plot shows that the .1uF coupling caps are way too
small... try
> 1uF it will kick up the low end real well...

I tried lot's of stuff. I liked 1.0 uF (non-ele) the best. 22uF (ele) were
nice too. 0.1s
were just a compromise. The filter still sounds basically the
same...whatever...

> H^)   harry

Tom




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