is the concept of a delay based sustainer? feasible?
for instance if you had a short delay set to many repeats
the repeats would then be "evened out" compressed and what have you
Im sure there is a reason that it wont work can repeats even be tamed enough to sound like there part of the same note
what happens when you mute the note you just played?
well there would be some kind of envelope generator and noise gate
Actually, a lot of delays operate with compression before, and expansion after delaying, to get rid of noise (using, e.g. NE/SE 570/571). You might experiment with bypassing the expansion phase.
Compression after delay means that you already introduced the time effect on your signal (in your delay), which means you are compressing a signal that is already decaying before you have had a chance to compress it. Remember also that in this case you will be compressing a signal which has been "mutilated" by the delay (lack of higher frequencies).
Maarten de Huu
I've cobbled together things like this with my DL4 and a momentary footswitch stuck in the expression pedal jack, to make both the mix and repeats on the delay fade in when the button is pressed, sounds really good (big!) on the end of notes, as the telltale attack doesn't get into the delay, so it loops into kind of a uniform, orchestral tone.
I also tried my boss NS-2 noise gate stuck into the regeneration loop of a modded DD3, but keying off the input signal so the gate closed and killed the runaway echoes when the guitar stopped playing. Kind of a reverse ducking delay. I think it was kind of cool for short delays, gave a repeat percussion type sound like on old organs.
The DL4 thing I'm guessing sounded more like what you were looking for, and could be done with any delay where you could simultaniously ramp up the mix, repeats, and possibly the audio volume going into the delay.
Not remotely DIY but on the subject of synthesizing sustain, the HOG has a cool freeze setting that is kind of a wavetable synthesizer that samples what seems like a very short section of audio and loops it in a way that doesn't have noticeable artifacts from the process, and is pretty convincing.