I received my M8 3 days ago and have been taking it through its paces. I like what I am hearing. It has enough power to drive even the difficult to drive HE-6 to acceptable SPL, though without much headroom. Everything else I throw at it is handled with finesse, clarity, and pleasing SQ.
All the switches for impedance, gain, and tone shaping work as designed except for the treble tone shaping switch. The only way I can obtain the highest tone shaping is by finagling the switch half-way between the middle and highest position. I assume there is a problem with the treble tone shaping switch such that it does not make a good connection when fully engaged in the highest position (far right). Has anyone else encountered this problem?
I am going to have to send my M8 back for a check-up. Since I also have to return my Dacmini for repair of the RCA Line OUT (Right Channel) problem, I will be DACless in Memphis until their return. I have complete confidence, though, that Centrance will handle these problems as they have with previous issues...with fast turn-around and problems solved.
EDIT: Looks like my attempt to edit was lost during a head-fi maintenance "time out." O.K...so here goes again... I hope this doesn't result in a double edit.
I mistakenly had the gain switch set to medium when first testing with HE-6 and the volume was not loud enough. I discovered my error and set the gain switch to High. This delivers more SPL than I can stand with the volume pot set at full volume. At 12 o'clock, the SPL is ~ 85 to 90 dB. I prefer it set to 11 o'clock so there is plenty of headroom for me, after all. There is no difference running with the power supply vs the battery.
HE6? Seriously? Do they sound as they should? My listening levels sound about as yours do, not too loud. I gotta find someone in the SF Bay area with a pair that wants to hear a HIFI-M8.