I've received a PM from someone else here who also doesn't care for the DAC, and I've had it running continuously for several days now with no improvement, so I'm thinking this DAC just isn't all it's cracked up to be. I've tried it with XLRs and with RCAs, my Threshold preamp, my Plinus preamp, and straight into the amp using a volume attenuator. I have not tried the USB, and the headphones only for a few minutes (nothing special there either).

Now there is a difference from the Arcam Blackbox, but it is only very slight. Actually when I compare my Audio Refinement CDP with it, the latter actually sounds better through its own RCA outs than through the DAC. I can't remember what kind of DAC my CDP has in it, but I've always felt it to be on the warm side, so it should actually sound more similar and it doesn't. I'm going to spend one more weekend tweaking things and if it doesn't improve, then it's going back.

Regarding the tubes, if I'm paying the same as LDB for the damn thing, it should have the same tubes. I'll crack it open and see what it has, but I better not find out that they screwed me on the tubes. I don't have any other tubes I can try (I'm kind of new to tubes), but I shouldn't have to do this 1 week after I own it, either. I know it was only $550, but if that's the pricepoint that the MH engineers determined could make a decent DAC, then they shouldn't be hobbling it for any reason.

I'll feel bad for AA if I decide to send it back (they've always been good to me), but I'm not going to keep something that doesn't make me want to listen to it more than what I already have.