MOTM

I think it sounds like a real alternative.  I don't know about the
mysterious workings of DIMMs, but for the one real electrical engineering
project I worked on in college, we used DRAM for (very slow) video capture.
More like a freeze frame, really.  At any rate, we used a fixed crystal to
clock the memory (and cpu).  Now, I don't know the mechanics / output of a
crystal, but I think it just outputs a pulse... which is similar to a square
wave at a small duty cycle.  So you get a simple square-wave-only
oscillator, use that to clock a A/D, D/A, a large counter, and memory, and
you're set...?  Most digital delays, I imagine, would mix the signals
digitally (so you get a really clean infinite repeat), but I think this
model would mix analog signals for simplicity's sake... no real cpu, after
all.

As a neat bonus, you could have the typical de-aliasing LP filter switch
between before and after feedback (always after the D/A, of course).  Before
feedback mode would produce the well-known damped-feedback sound.  After
feedback mode would produced ever-more-aliased feedback, for a possibly
weird sound-munging effect.  (Or maybe you would just turn off anti-alising
all together?)

The problem here, I think, would be getting those really-short delay times
that digital delays can easily handle.  Digital delays can easily control
which memory location they start and stop reading from.  This hybrid delay
would always run its course through the entire memory; shorter delay times
would read the memory faster.  Or would that just produce a pitch bend
effect...?

--PBr, early-morning blabber, half-asleep and confused in general

> -----Original Message-----
> From:	Tkacs, Ken [SMTP:ken.tkacs@...]
> Sent:	Thursday, April 20, 2000 6:00 AM
> To:	'MOTM Forum All'
> Subject:	[motm] Delay Module
> 
> 
> How feasible is this idea of creating an 'analog delay' using digital RAM?
> Is that an oxymoron, or is this a legitimate concept?
> 
> The good points of course are that you don't need bucket-brigade device
> chips that will go out of production, and extensibility. It sure would be
> cool if such a module could be based on, say, PC EDO RAM DIMMs or
> something,
> with lots of extra sockets so that DIMMs could be added later.
> 
> Think about it-a few years from now when your Pentium III is a boat
> anchor,
> you can throw the PC out and move the RAM into the delay module to get
> some
> real use out of it!
>