> Again, coming from a total electronics dumb-bell, with such small
> delay times couldn't you do this with discrete parts?
Not really. You need to have several steps:
1) Conversion and storage means on the incoming audio. A BBD chip is a black of many small
capacitors (like 512 of them). There are 512 analog switches inbetween them. The audio (AC
voltage) is "dumped" on a capacitor.
In digital delays, the audio runs through an ADC (analog-to-digital converter) and the sample is
stored in RAM.
2) Output conversion means from storage to audio. In a BBD, this is "free" because you are
retrieving the original charge (OK with added noise and 'droop'). In a digital delay, that is
done with a DAC (digital-to-analog converter).
3) Clocking means. This "shifts" the sample along in the storage means to get a delay. If you
have 512 BBD stages, and you want 5.12ms of delay, that's...errrr...(looking for slide
rule/MathCAD/abacus) a clock period of 10us or 100Khz. Most BBDs won't operate this fast, which
is why you see "minimum delay" in the 10ms range. In the digital world, we can go
full-tilt-boogie and "cheat" by picking off from ANY RAM location. A BBD has fixed "taps" and so
we are forced to chug through the whole thing.
Paul S.