I ordered a quadraverb, because I honestly find that it is hard to make the axe fx sound shitty/like early 90's digital processors. The ways you could hook it up are midi connection, stereo fx loop, or even send the SPDIF signal from the quadraverb into the axe fx spdif. I think everyone on this form is right that the fx sounds way better and you "should" just use those mod/verb/delay fx on the axe. But shit some of the sounds on the quadraverb are so quirky and have that great 90's shoegaze vibe. So I am going to use the quadraverb for layers. The axe is so high quality, but it is hard to get that really uinique 90's digital lo fi. Literally anything else is doable, and it is do able to get that 90's tone out of it with the mods/verbs/delay/ pedal in the fx loop, but the timbre/character is not as exact as those early digital processors. Yeah making a whole record with a quadraverb would be hard, but using it for layers with the axe could equal some awesome songs. Cause alot of 90's records used digital racks for verb, delay, mod. ( plus running all that through eq, mixing boards, compressors, limiters, early digital editing gives a more polished sound) I would argue with the axe and quadraverb you could attain that high level of studio quality/processing with older digital processors.