Digital delay

This is a rather nice sounding digital delay based on the HT8972 chip. I bought it as a DIY-kit from Velleman for about 20 euros.

I've done some smaller changes to the circuit, most noticeable omitting the microphone and microphone preamplifier as well as the output amplifier. I also changed the delay time range by using a 100k potentiometer instead of 22k (RV2) as well as 1k resistor instead of the 10k (R2). Since I have a +5V option installed in my modular I made some changes at the power supply input.

Unfortunately there are no building instructions for this module, but at least you'll find the schematic, some photos, and some comments.

Schematic, this is the original schematic by Velleman more or less straight out of the datasheet for the HT8972, with my changes on. Parts marked with red are the omitted parts, markings in blue are my modifications. At the power supply input I've inserted links at D1, SW1, and R10. C1 (100nF) is changed to C24 (100uF), and ZD1 is changed to C1.
  1. The finished module, without a faceplate.

  2. The finished module.

  3. Here's a demo of the delay.

That's it! Have fun and create some echoing space!


Updated - 2013-10-13 13:17
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