[sdiy] BBD help

[R. Drake]

on 1/23/04 5:23 PM, Joseph Craig at blitz at nmt.edu wrote:

Ken Stone is working on finishing up an evaluation board:
http://www.cgs.synth.net/, listed as CGS44 on his "PCBs for Sale" page.

lbd 



> 
> 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
>>> 
>> 
>