[sdiy] Digital Delay - smoothly varying the delay time

[Florian Anwander]

Hello Tom

> Do commercial delays work like this? Do you notice a delay when you twiddle the delay time?
I'd say out in the commercial wild all variations you mentioned exist.

All old Roland Delays (SDD-1500, SDD-2000, ...) simply muted the delay 
while changing the delaytime.

Early Korgs use up/down buttons and delay the variation. The SDD3000 can 
count up/down in 1ms or 10ms steps. I estimate that the change rate is 
at 5 steps per second. It takes quite long to come from 10ms to the max 
delaytime of 1024ms. There is no hearable artifact.

My Solton DDL-1500 worked similar, but the change rate ist faster. I 
think they decrease the frequency range of the delayed signal(!) with an 
filter in the output while changing the delaytime, so no artifact noise 
comes through.

I own two Vestakozo DIG-20's which have hearable zipper like artifacts 
when the delaytime is varied quickly - I love them that for (but those 
Vestzakozos are pure electronic punk anyway).

Florian