BassStation Filter: What is it?

[mark verbos]

you are all in luck....

http://www.asahi-net.or.jp/~WZ4K-TNK/syoyuu/bsk.html

Rob wrote:

> Well, I remember way back when, I looked into the unit and I didnt see the
> telltale signs of a ladder filter ie neat rows of transistors/capacitors.
> Unfortunately, I don't have one on hand to check out right now.. I am sure
> once the rack unit I bought comes in, it will prlly only take me an hour
> with my scope to figure the thing out.
>
> Also, a state variable filter would definitely be easier to produce the 2
> pole/4 pole configuration that they used.
>
> As far as the VCO, I question whether it has a VCO at all. I get the feeling
> that it has a DCO driven from lookup tables in the uP.. I dont remember it
> ever going out of tune, so this would point to to a uP DCO.
>
> Nothing wrong with this, but you definitely don't get the warmth of analog
> with the DCO.. Still sounds good, but just a bit too perfect.
>
> Thanks
>
> Rob
>
> ----- Original Message -----
> From: <metamatic at webtv.net>
> To: <synth-diy at node12b53.a2000.nl>
> Sent: Saturday, November 25, 2000 8:51 PM
> Subject: Re: BassStation Filter: What is it?
>
> > cyborg_0 at iquest.net wrote:
> >
> > >Anyone know what kind of filter is
> > >crammed in there? From what I
> > >remember, it was some sort of state
> > >variable filter, but I am not all that sure.
> >  >Perhaps someone has some schematics?
> >
> >  I have the keyboard version. The VCF has two modes, both lowpass. The 2
> > pole mode is meant to suggest a TB-303 filter, somewhat unconvincingly,
> > IMO. The 4 pole mode, however, does a wonderful job of emulating a Moog
> > VCF. I think it sounds quite a bit like my ancient Source, and along
> > with the bonus of factory MIDI, I don't have to worry about damaging a
> > rare membrane switch panel.
> >
> >  I'd love to see schematics as well, if only to see how the different
> > cutoff slopes are achieved.
> >
> > Richard Hess
> >
> > metamatic at webtv.net
> >
> >

--
mark verbos

"if you want something done right, build it yourself."

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