Yahoo Groups archive

Cgs synth

Index last updated: 2026-04-28 23:16 UTC

Message

Re: PT2395 Delay

2004-04-04 by sasami@hotkey.net.au

>I'm using a vco from a 4046 PLL as the clock so I could get voltage
>control but, it seems to change the pitch of anything that has already
>went into the delay if I change the clock speed before it's echoed back
>out. Is this to be expected? If so, then I don't see why voltage control
>would be all that useful?

It is the correct behavior. This sort of thing is used to do flanging and
chorus effects, though admittedly the delay time is a bit too long for that
here. That is why there is provision to cut a couple of the address lines -
to shorten the delay.

In this case VC of the delay would probably be most useful for remote
setting of the delay, for example by a computer, so that the delay could be
saved along with other settings in some setups.

When running shorter delays, it is also useful for changing the "resonant
frequency" of the echo loop, when a lot of feedback is used.

>also, the output seems to be a lowpass filtered version of the input
>with a fairly low cutoff frequency. I'm loosing all the higher
>frequencies. The input and output sound exact if I filter the input and
>put my oakley multiladder cutoff at about 1/4 of it's range. Sorry, I
>don't know what frequency that would be. Is this what it does, or did I
>do something wrong?

You may have a wrong capacitor value - I had a similar problem at the start.
Another thing - when run in the meduim and long modes, a second filter kicks
in to remove the lower clock frequency. Keep it running in the short mode
for the best bandwidth.

Ken
_______________________________________________________________________
Ken Stone sasami@... or ken@...
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.