This post is probably only for the intersection of the #Venn diagram with circles labelled "#guitar player" and "#electronics hobbyist". I'm not on fora like #diystompboxes and such, so here it will have to be.
Like many others, I've built delay / echo #pedals / circuits using the ubiquitous #PT2399 digital delay IC. They're dirt cheap and simple to use. But the lowest delay period you can use them for is too long for some things, like #flanger / #phaser effects, or even some types of #chorus effects.
But I haven't seen much discussion of alternatives. I've been playing around with one I've built using the #M65831 digital #delay chip. It's not quite as cheap as the PT2399, but you don't have to look very hard to be able to get them for a couple of bucks (Canadian). But it seems to be so much better in this application.
First, it's designed and documented so that you can use a crystal to set its clock OR drive it directly with a CMOS-type square wave. No fiddling with drain currents and on-reset latchup problems.
Secondly, it sounds (to my ear) far better than the PT2399. The #datasheets I have for the PT2399 don't state a sampling rate; the M65831 uses 500 ksamples/s for lower delay times.
Thirdly, the range of delay available is larger. The shortest documented for PT2399 is ~31ms. For the M65831, it's 12.3ms using the default clock of 2 MHz. But the one sample I've tried is happy to run at 6 #MHz, for a delay of ~4ms. That's short enough for #flanging!
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