Bel Canto Dac + SinglePower MPX vs. Headroom Desktop Max w/ Max Dac & DPS

[Iron_Dreamer]

Quote:

Originally Posted by MikeLa Iron_Dreamer, I take it you haven't sampled the Headroom MaxDac, it sounds like you used the MaxAmp and the DAC in your soundcard?

Yeah, but it was the previous version of the Max amp, the one with the gigantic solid metal faceplate. A joy to look at but the sound was not overwhelming by comparison to what I had at the time. Ended up selling it after a short while.

 

[Beauregard]

Quote:

Originally Posted by thomaspf I did not know any of the headphone DACs has a jitter reduction clock. I thought the Max DAC simply uses an AD1896 asynchronous resampler similar to the Benchmark DAC1 or Bel Canto DAC2. ...

My less-than-expert understanding is that all implementations using the AD1896 reclock the signal with an internal crystal clock before the datastream is passed from the SRC to the DAC chip.

I thought that was the purpose of using an SRC. Input signal arrives at receiver which uses a wide bandwidth PLL to recover a jittery word clock. It's then passed to the SRC which has a low-jitter narrow bandwidth PLL and resampled stream goes to DAC - with both SRC and DAC referenced to the same crystal clock. Thus, the DAC sees a virtually jitter-free datastream, independent of the clock in the incoming signal.

Please correct me if I'm wrong about this!

Best,
Beau

 

[Voltron]

Quote:

Originally Posted by MikeLa Voltron, I can't wait for you impressions.

MikeLA-
Well, I wish I had more time at the office before I had to leave the new acquisitions behind. I also bought a new pair of K601s yesterday but left them to keep the Desktop rig company over the weekend. I got in about 15 minutes of listening time on the 601s and about a half an hour through my crap computer speakers. Although I can say the sound quality seems excellent and that the amp is very powerful, there was an issue I guess with the DAC because the sound was glitchy. There were errors that sounded like skips/gaps in the sound that I couldn't figure out in the short time I was playing it. I was using a cheap USB cable out of the dock that my laptop sits in. I have played those rips many times and I also tried a CD direct and I got the same result. On monday I am going to try out the S/PDIF output on the dock and a better USB cable if I can find one. It was odd and a bit disappointing, but I had so little time to figure it out that I am not sweating it too much at this point. Anybody reading this who has an idea on cause, let me know. More and hopefully better impressions to follow Mike. I am listening to my MPX3 while typing this out just to keep that sound fresh in my mind!

Sloth-thanks for your comments earlier. I think on high gain this amp could easily power some reasonably efficient speakers--it drove some cheap computer speaks easily and loudly. I am going to give it a try, although I will have to figure out an RCA-to-spade/bare cable solution.

 

[thomaspf]

Quote:

My less-than-expert understanding is that all implementations using the AD1896 reclock the signal with an internal crystal clock before the datastream is passed from the SRC to the DAC chip.

All of this is correct. What is missing is the fact that the data is being asynchronously resampled as well. As a result a different set of bits is sent to the DAC chip. This happens even if there is zero jitter and just clock shift between the sender and the internal clock. Jitter and clock shift are remapped to noise (low level) in the PCM stream by the AD1896. This is better than no dejittering at all.

Synchronous reclocking solutions, do exactly what you describe above. They reclock the stream based on an internal crystal but they do not change the bits. Examples would be Apogee, Weiss, or Lavry.

Cheers

Thomas

 

[Beauregard]

Quote:

Originally Posted by thomaspf All of this is correct. What is missing is the fact that the data is being asynchronously resampled as well. ...

Thanks for the confirmation - and clarification. I misinterpreted your previous post as implying that SRC DACs didn't reclock the datastream.

Best,
Beau

 

[MikeLa]

Voltron
How does the office rig compare?