you can do it with any delay block, feedback 100% with tails active, momentary footswitch on bypass state, hit the button, it grabs whatever is going through it, release button and it holds it forever...
only problem is with the delay units there's no way to clear the buffer without turning down the feedback again manually. I really wish there was the setting to clear the delay buffers on bypass, while also somehow holding tails, that would make every delay the equivalent to that $300 freeze pedal...
you could momentarially open a runaway oscillating modulating tape machine, feed it some little tidbit of noise, then get off of the footswitch while it runs away, then hit the switch again and it goes dead silent empty and starts again from scratch. If you want to stop the runway just tap the switch quick without playing
...2 hours later: ok so you can assign more than one function to a switch, try this, delay bypass on momentary FS1, delay feedback on momentary FS1, feedback inverted to min=100 max=0, so FS1 bypass state turns off the delay (with tails active) and turns up feedback to 100, holding whatever was in it to infinity. With tape modulation and distortion it gets real nice as it washes out. Hit the button to activate delay and grab something else, it puts the feedback at 0 whenever you turn the delay back on, it doesn't wipe the buffer all at once but it overwrites that section of the buffer for as long as you hold the button down, you can tap it real fast and grab noises and make a patchwork of insanity by tapping the button real fast and playing all over the place with noises and scratches and bends. (warning: preset makes noise by itself) I HAVEN'T HAD THIS MUCH FUN IN A LONG TIME
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