I got a bunch of PT2399 echo processor IC's off ebay for pretty cheap.  According to the datasheet they were introduced in the late 90's and applications include "Karaoke Machines".  Supposedly they're a decent approximation of tape delay.

I haven't messed around with them yet, planning on using them for reverb/echo fx on some chip MIDI modules I'm designing.

Anybody have any input on these things?

Montreal, Canada

They don't sound like tape delays to me, but that doesn't mean the effect isn't cool as balls though. I guess you could contact this guy for his schematics:


I bought a bunch several years ago too, but at the time I did not have a dual power supply. I should pull them back out.


this is very easy and straight foward : … board-bom/

you could make it on perf board or just buy the PCB from synthrotek

either way its a decent resource


Hell yeah these chips are awesome, I bought a bunch of them to put inside circuit bent/diy stuff.  Also I think they're the same chip used in the Monotron delay and 99% of the cheap delay/reverb pedals on ebay.

I built the example circuits from the datasheet on breadboard and just played around with resistance values until it sounded good. You can make really long glitchy delays. Its also fairly easy to add a feedback 'repeat' loop to the circuits with a bit of experimentation. I remember it being a pain to get the example circuits working at first and had to rebuild it a few times with diff values hmm

Last edited by rot (Mar 28, 2015 12:24 pm)