I auditioned the ASL (v.1) vs. the X-Cans (v.2) with my HD600's, and bought the MF unit for its superior sound (the ASL, much as I liked it, just sounded too 'tubey' [or 'transformer-y' - I believe it was transformer-coupled] in an obviously colored sort of way, even with upgraded tubes, while the MF [also tubed, but direct-coupled] sounded more neutral, dynamic, and faster, though I don't know about the latest versions of each unit). However, the unique, plastic-encased output jack assembly on this v.2 of the MF is just a terrible part - I've been through two of them already and need another one, because the extremely thin, flexible contacts inside deform way too easily over time and you begin to lose one channel, eventually completely. This part, which solders directly onto the PCB, cannot successfully be opened up and repaired (I've tried - it self-destroys), and a replacement is hard to get, so next I'll be attempting to retrofit a conventional heavy-duty, unencased phone jack (something the latest v.3 appears to have switched to, judging from photos of its front panel), though I'm not yet sure I'll find the necessary clearance inside. You've been warned...
