[mink70]

I'm wondering whether anyone can weigh in on a strange issue. I'm listening to Amarra 2.4.1 from a MacBook Pro with 4G RAM outputting to a newly acquired (used) MHDT Havana tube DAC. I have to admit that I can't figure out what's happening. Fact is, it's sounding different from day to day. When I first listened to it  a week ago, from a Mac over USB, it sounded kind of edgy and still wiry in the treble. After a few days, the sound changed to the point where it began to sound very soft, with rolled off treble, reduced dynamics and detail. I figured that the new tube had burned in, but a day later the DAC was sounding forward and big again, with an edgy treble. NOTHING else had changed. This has been the story all along. Some days the Havana sounds lush and lovely, others it's edgy and harsh—even when nothing else has changed. Then I got a message in Amarra, after a few hours of playing, that I was running out of memory. No other apps were open. 2 gigs were allotted to memory play. I'm trying to figure out whether the DAC or Amarra/Mac are causing this. I know this sounds weird. Has anyone experienced anything like this?

 

[SwanSong]

I read your post and I was wondering do you think the external dac made a big difference in sound over the built-in dac on MBP? I just bought studio monitors and they sound great just using a RCA adapter on the 3.5 output. I had my heart set on a tube dac though but now I'm not sure. Give me your opinion since the Havana is also a tube dac.