MisterX built M^3 for sale. Has bass boost and loop output. Op amps 637L/637R/627G. Comes with a standard elpac ps. Unsure of the gain but I used it with senns, grados, ultrasones without a problem. The amp is about 6 months old, I am the original owner. Asking SOLD shipped and paypaled. Shipping to the conUS only. Thanks for looking.