I dont use the hold feature, but from what I recall, you set the far right knob in full clockwise position, and adjust the delay time knob to set the sample length (up to 0.8 s). You play your 0.8s sample and then immediately press the pedal down. It captures that last 0.8 s, and plays it back as a loop. It can be pretty cool, but the sample length is too short to be of much use.
I love mine (bought it new about 11-12 years ago). It has been to dozens of gigs, and bashed around a lot - but has never failed me. It devours batteries though. Use an adapter - although this has been its only source of problems during a gig. Lately I've taken to putting a new battery in before gigs. I think you need to remember to remove your cords when you're not using it - otherwise it will drain your battery.
I mostly use mine as a slap-back, and go for a light reverby type setting (low level, low repeats, shorter delay times).
Good luck!
I just snagged a blue label Boss DD-2 Digital Delay. I bought it to contrast the sounds of my DM-2 Delay. I've played around with the DD-2 a little, but I can't seem to figure out the "hold" feature. Can anyone tell me how it works? How long of a "sample" does it hold? Any help is greatly appreciated. Thanks!