[sdiy] Digital echo chip

[Scott Bernardi]

Yes, I'm definitely going to get one.  What's funny is that they datasheet
that was on Jameco's page was the full one, and they only had a summary
datasheet on the Princeton site!.
The DRAMs it calls for are standard 41256 or 4164.  It has a range of 100ms,
150ms or 200ms delay in fixed mode using the 64K DRAM, which can be varied by
about a 2.5:1 range by varying the clock rate (with a pot).   WIth 256K DRAM
it will go to 800ms.


Scott Gravenhorst wrote:

> It's another of Murpy's Laws that says the site you
> looked at casually yesterday will be down today simply
> because now you NEED it.
>
> The data sheet talks about "1 bit digitized" as "ADM"
> modulated, and they don't define "ADM" per se.  The DRAM
> needed is single bit wide.  I wonder if this is some
> kind of PCM ??  They don't describe the digitization much
> other than that, so it's hard to know what digital resolution
> is attained.  They call it "low distortion", but show
> different distortion specs, one is 3% THD, the other
> 0.4% THD.
>
> But who knows, for $3.95 it could be fun at least and
> might well be better than Happy Harry's nemesis, the BBD.
>
> If you get one and play with it, I for one would like to
> hear about your discoveries with it.
>
> Scott Bernardi <sbernardi at attbi.com> wrote:
> >I came across the PT2935 (Princeton Technology) digital echo IC at
> >Jameco (www.jameco.com) for $3.95.  The delay can be continuously
> >variable with a resistor. You can supposedly get up to 800msec of delay
> >with an external 256k DRAM chip in extended delay mode. There was a very
> >minimal datasheet on the Jameco page. I got to the manufacturer's
> >website yesterday but today it seems to be down (www.princeton.com.tw).
> >Anybody have any experience with this chip?  It looks pretty
> >interesting, and it's cheap enough.
> >
> >--
> >Scott Bernardi
> >sbernardi at attbi.com
> >
> >
> >
>
> =========================================================
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>
> -- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
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--
Scott Bernardi
sbernardi at attbi.com