869820 Thats tha link if anyone can read it
Nope. Linky no worky.
But it's $1800 and it's a flagship. Any issue is unacceptable for that price if you ask me.
That is exactly the issue that I've been trying to track down. The problem does seem to be in the DAC itself. Here is what seems to trigger the issue:
1) Full 24/192 tracks. If you pull away from that sample rate or down sample, the problem goes away. Also, the issue doesn't show up on all 24/192 tracks but the tracks it does show up on, will consistently repeat the problem (which is strange that the content of some tracks will trigger the issue and others won't. In fact, some tracks that I have, the hiss actually ramps up at the beginning of the track and will always do it the same way!)
2) Some kind of very fast source such as Bitperfect, Audirvana, or even WASAPI feeding a sound card in a particular mode (probably EVENT DRIVEN).
3) I'm becoming pretty sure that it only happens when the Asynchronous transfer mode over USB is being used. If you use a synchronous (i.e., adaptive mode) I don't think the problem occurs. For example, if you are using WASAPI in PUSH mode you probably won't see the issue as I think the PUSH mode is synchronous.
It is as though the DAC reaches a processing "overload" of some type and it triggers the rise in noise floor. The Asynchronous transfer mode probably does much more handshaking than the traditional synchronous (adaptive) modes adding to the overhead.
My big issues with this is that the Asynchronous mode normally eliminates all issues with jitter due to cabling, PC power supply, PC clock, and interrupt service routine overheads in the OS, basically providing some significant improvements in playback for systems capable of revealing that level of detail. Exactly what you would want on a new flagship DAC. If the Asynchronous mode is really contributing to this problem, I'm now forced to either down-sample my hi-rez files or use an older and inferior USB transfer mode (i.e., adaptive) in order to listen to them.
For what it's worth, my guess is that when the glitch happens, the PCM to SDM translation in the DAC might be getting messed up. Since the SDM stream is processed out of the PCM data, it might be sensitive to low volume data patterns in the initial PCM of the track. This could explain why some tracks trigger the issue and others don't. But these are nothing but guesses on my part. Without knowledge of the guts of this product and some logic analyzers to track what's happening in the HDVD800 and the USB connection, we are completely dependent on Sennheiser to tell us what is happening.
One way or the other, 24/192 USB for some Hi-rez files is unusable and I would like to know if this is fixable or not and whether or not it WILL be fixed. If Sennheiser takes no real interest in this, I'm dead in the water with a $2K DAC/amp combo that is limited to useful digital data rates of only up to 24/96 USB (and 24/88.2 for optical).
I have forwarded another email Jeff to Sennheiser USA. My last four have went unanswered and I wont continue writing the review until I have all the facts. If they dont answer me on the last email I will try to get Axel;l Grell to address the issues you are concerned with and the information I need to write this review and have it done right.
What are the track (song) names and albums that they came from (i.e., the ones that have the problems)?
I don't want to exaggerate the issue, apart from these two tracks, it sounds phenomenally good.
C.C Coletti - Artist
Album: Bring It Home
The two tracks that have the background hiss:
Bring it on home
Format: ALAC 24/192
USB Cable - D-Fi Vertere Pulse
Oh and the album above is definitely worth a download...! First track just sounds incredible with my HD800 + HDVD800 - I'm willing to forgive any foibles just to hear it again...I come home each evening and play this track in my study before dinner...
I will try to duplicate these later as I know have some high resolution files on a hard drive so i can try to see if I hear any hisses. I am using the Oppo dac now and hear nothing so tomorrow I will play them on the sennheier dac
I just bought the album to test, and like you I got hissing. The first track sounded just fine, and when it then switched to "When The Levee Breaks" there was the really loud hissing as if I had suddenly tuned out of signal. Turning on resampling in Foobar2000 fixed it. Haven't encountered this issue before this. Very strange.