[sdiy] BBD help

[Matthew Valdes]

http://www.generalguitargadgets.com has a project using the PT2399
I've built it and couldn't be happier.

Matt

>From: Joseph Craig <blitz at nmt.edu>
>To: Harry Bissell Jr <harrybissell at prodigy.net>
>CC: Shokwave <shokwave at nb.aibn.com>, <synth-diy at dropmix.xs4all.nl>
>Subject: Re: [sdiy] BBD help
>Date: Fri, 23 Jan 2004 15:37:19 -0700 (MST)
>
>
>the PT2399 has built in ADC & DACs.
>
>-Joe
>On Fri, 23 Jan 2004, Joseph Craig wrote:
>
> >
> > I think you were talking about...
> >
> > Princeton PT2395 Enhance Digital Echo IC
> >
> > I also wanted an analog delay, but after checking prices on BBD chips 
>and
> > going through all the design work, I have decided to go with a quality
> > digital solution.  Has anyone designed with the PT2395?  looks decent.  
>I
> > just need to build a delay module for my modular synth.
> >
> > -Joe
> >
> >
> > On Fri, 23 Jan 2004, Harry Bissell Jr wrote:
> >
> > > <harryrantmodeon>
> > >
> > > The BBD is indeed a candidate for a short, low quality
> > > audio delay...
> > >
> > > ... and you WILL filter it heavily as well (like it or
> > > not)  ;^P
> > >
> > > My rants have the following points
> > >
> > > 1) The BBD has very low quality ~unless~ you add a lot
> > > of extra circuitry to it, usually high quality
> > > multi-pole filters at the input and output, and
> > > usually
> > > some companding (NE-570 and ilk... know what an ilk is
> > > dont'cha... its a small MOOSE).
> > >
> > > 2) See the JH "Storm Tide Flanger" for an example of
> > > how much hardware it takes to do it 'right'
> > >
> > > 3) BBDs are unforgiving chips, a wrong wire, or
> > > slipped probe is DEATH.
> > >
> > > 4) most NEWBIES who are the least well equipped, both
> > > on the workbench and in experience... say "I want to
> > > make an audio delay as a first project" without
> > > knowing what they are getting into.
> > >
> > > 5) DIGITAL delays are cheap today as well... Princeton
> > > Technologies makes the PT- (something help me here)
> > > which will do the delay better than most BBD circuits
> > > at the same cost.
> > >
> > > 6) BBDs were the 'only' sub for tape echo in their
> > > day... but that day is long past.  Digital delays are
> > > going for cheap new, and cheaper used.
> > >
> > > so if you want to explore the BBD for educational
> > > purposes, go for it. If you want an audio delay of any
> > > quality... there are better faster cheaper ways to go.
> > >
> > > </bbdrant>
> > >
> > > Bffzfftppssszzzzz..........
> > >
> > > H^) harry  (who actually HAS a few BBDs in stock...
> > > might use them someday :^)
> > >
> > >
> > >
> > > --- Shokwave <shokwave at nb.aibn.com> wrote:
> > > >
> > > > ----- Original Message -----
> > > > From: "Magnus Danielson" <cfmd at bredband.net>
> > > >
> > > > > From: Scott Gravenhorst <music.maker at gte.net>
> > > >
> > > > > > Just don't mind Happy Harry when he goes into a
> > > > BBD rant...
> > > > >
> > > > > Actually, on rare occasions he will motivate it
> > > > very well, and then also
> > > > give
> > > > > you insigh into what needs to be done to make it
> > > > fairly decent.
> > > >
> > > > AHA! Well, time to ask then:
> > > >
> > > > I want to delay an audio signal by a small
> > > > (preferably variable, but there
> > > > is a possible use for hardwired) amount, and mix it
> > > > back in.  It doesn't
> > > > have to be high-quality, I'm probably going to
> > > > filter it all to hell before
> > > > I mix it back anyway, and a BBD seems like the
> > > > obvious place to start. By
> > > > "small", I mean 1-50 ms or so, maybe even just 1-20.
> > > > Sooooo...is there any
> > > > good canidate IC for this? I figured maybe there was
> > > > a BBD made that was so
> > > > short a delay that it was useless for most
> > > > "delay/chorus" projects, and thus
> > > > cheap and still easily available. Or is there an
> > > > easier way to go about
> > > > this?
> > > >
> > > > -Darren
> > > >

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