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Sennheiser HDVD800 Headphone Amplifier - Page 75

post #1111 of 2430
Quote:
Originally Posted by GSARider View Post

That's the thing, it's pretty easy to sit online, blow things out of proportion and trash good products. Consistently, on this thread, owners of the HDVD800 are happy with their choice of DAC/AMP. Personally, I'm happy with mine, I'm not concerned about hissing on a few tracks at 24/192 that have issues, whatever the reason.

Overall, the HDVD800/ HD800 combo is phenomenally good, so much so, I'm thinking of buying another combo for my Office use.smily_headphones1.gif 99% of my tracks are 16/44 CD Rips , so am I bothered..wink.gif

I'm not crying about it's sound quality, but a flagship that's $1800 shouldn't have these stupid problems.

That's like buying a $5000000 Ferrari and then it turns out its top speed is 50 km/h.

 

I'll be known as the realistic pessimistic bastard on Head-Fi.

 

Anyway, the output impedance was 43 ohms right?

Couldn't I put a resistor between my V200 and the HD 800s and listen to them "the way the artists intended it to be"?

I guess that 25-50% of the tracks that I regularly listen to this is ripped DSD... Sennheiser where is the perfect DSD-DAC for wubwub?

post #1112 of 2430

So you don't have one and are definitely not buying an HDVD800 right? Time for you to post your V200 problems on the correct thread for them.wink.gif


Edited by GSARider - 6/23/13 at 7:00am
post #1113 of 2430
Quote:
Originally Posted by wisemanja View Post

 

Frank, My guess is that if the 24/96 files that you were using had an excess of ultrasonic audio data in them, you would also hear the hiss on them when using the HDVD800 (so it IS in part the files). But there would still be no hiss on the Oppo (because it is probably designed to filter the ultrasonics out of the file prior to conversion). I am sure that all downconversion algorithms must apply a low pass filter to the data since it is being moved to a lower sampling rate, and therefore a lower Nyquist frequency. In other words, it may just be that the normal production of 24/96 (and lower rate) files statistically results in fewer files containing ultrasonic data. Especially if most recordings are mastered at a high rate and then down-converted to a lower rate that is finally sold.

 

I think that the main issue is exactly as you've pointed out, if a file appears to play just fine on one DAC but doesn't on a much more expensive one, there is certainly a customer issue that must be addressed (i.e., Sennheiser's challenge at the moment). When the problem occurs, it is triggered by audio files that don't meet spec. But having files that are out of spec won't always result in hiss since some DACs (e.g., the Oppo) will massage the file and bring it into spec prior to conversion. The HDVD800 does not currently seem to do this, hence the hiss issue.

 

But I'm not sure that this necessarily makes the DAC "defective". The thing that is really intriguing to me about all this, is the question "Should a DAC be required to repair all out of spec audio files that are sent to it"? 

 

1) One customer might justifiably say "Yes, I don't want to hear noise based on my audio files being screwed up and not built correctly"

 

2) Another might also justifiably say "No, I don't want the DAC to try and hide the fact that I just purchased expensive high rate files that are fakes" (e.g., original files recorded at 24/48 and then up sampled to 24/192 and sold for twice the price).

 

When I purchase a 24/192 track, I expect that it has more information in it than a 4x up-sampled 24/48 track. That's why I bought it in the first place. I don't want hi sample rates just for the sake of using up more storage on a music server or to see how effectively someone's up-converter algorithms can fill in the holes. I want to hear what was in the original recording.

 

3) Another customer might say "No, I don't want any other non-essential processing on the audio signal being done, I want it as clean as possible" So if the high resolution 24/196 Khz audio file marketplace in general sell files that meet industry standards, and if adding the additional processing to pre-filter audio files adds cost and potential sound degradation, then this would be a no brainer--don't add the pre filtering.

 

4) But what does customer 3 above think if the bulk of the hi resolution file industry is just being sloppy with their file formatting. True High resolution tracks that have just not had the ultrasonics cleaned out like they were supposed to. And what if it is fairly cheap and easy to add the preprocessing needed in a DAC to handle such file without noticeable sound degradation? Then the answer would likely be "Yes, give me the convenience of hearing my high rez files without audible artifacts due to their poor fi;e formatting"

 

There are several variables here that I don't have a good feel for (such as the extent of incorrectly formatted files in the hi-res industry), but since I'm sure that there are a lot of customers like customer 1 above, and since Sennheiser currently only supports cutomers 2 and 3 already, I am keen to know what they come up with.

 

- Jeff


I do understand the problem here now.

I think the easiest fix is to use software. They can provide a checking and converting tool to the user and let the user decide whether or not the "format" the file into HDVD800 readable ones. (Pre applied low-pass filter or file re-formatting). Since it is a change done to the digital source, I do not think we need to do it in real time~~~~~

 

Just my guess, not sure it is easy as it sounds.

 

P.S.

Anyone try to adjust the gain switch while using the DAC? Does it do anything funny?

post #1114 of 2430
Quote:
Originally Posted by AlanHell View Post


I do understand the problem here now.

I think the easiest fix is to use software. They can provide a checking and converting tool to the user and let the user decide whether or not the "format" the file into HDVD800 readable ones. (Pre applied low-pass filter or file re-formatting). Since it is a change done to the digital source, I do not think we need to do it in real time~~~~~

 

Just my guess, not sure it is easy as it sounds.

 

P.S.

Anyone try to adjust the gain switch while using the DAC? Does it do anything funny?

 

That would be really nice if possible, but the issue might go much deeper than that. Digital signal processing can require extremely fast processing speeds. That's why much of it is done on the big IC chips (e.g., the Burr-Brown converters used in the problem). Customizing ASICs and then retooling for  manufacturing is not trivial. Any general software processing outside of the main chips is going to typically be limited in it's capabilities.

 

And as I've alluded to in my postings, I'm still not really sure exactly what the problem is other than the HDVD800 doesn't handle the excess ultrasonics in some data files. For example, in the spectrograms in post #1083 you can see that the ultrasonic noise on the St. Louis Blues soundtrack is at about -50 dB. Well the music in that track also runs about the same level. (in other words the "volume" of the  ultrasonics that shouldn't be there is about the same as most of the music that is supposed to be there). This track created significant hiss. On the other hand the "Stank" soundtrack's ultrasonic data was at -85 db which is only -35 dB below the problem causing ultrasonics on the "St. Louis Blues" track. However it is still 30 db higher than it should be (around -115 dB). Why doesn't it create the hiss? 

 

Maybe it does and it's just much quieter, You'd need instruments to tell. My point is that although I know that noise in the track that is above the Nyquist frequency can produce aliases in the audible range, I'm only posing as Inspector Gadget here. What if the Burr-Brown chips were already designed to handle this contingency? That would mean that something else isn't right.

 

Here's a great example that has existed occasionally over the years where people have been surprised that an expensive set of interconnects were needed for a fix. What if it is the analog part of the Amplifier section that is going loopy in the presence of noise in the 85 kHz region? A lot of wide band amplifiers designed as audio amplifiers might have a bandwidth going up to 1 Mhz, however their distortion characteristics were are only monitored in the audible ranges (you're only going to put audio data through it, right?). If Radio Frequency noise picked up in ground loops gets into the front end of that amplifier, you can get audible artifacts. For example, if an RF signal at 900 kHz and one at 901 kHz (both of which are not audible) are present and the amp has a high intermodulation distortion in that range (and I know that many have over the years), one of the intermodulation products you will get is a 1 kHz tone which is DEFINITELY audible!

 

So there is even a possibility that isn't too extremely remote, that the problem could be in the headphone amplifier section of the HDVD800. Does the HDVD800 have an extremely low set of distortion characteristics at the top end of the bandwidth? I would hope so but without any spec sheets on the product it is anyone's guess (which is what I'm doing here)

 

Hence here are a few reasons why I have so much fascination about the current issue. I know enough to be dangerous (as they say)ksc75smile.gif

 

By the way, this latter issue has resulted in some fascinating design techniques in analog interconnects over the years, usually in how they do the sheilds. One way is the "telescoping" shield. this is where an inner shield carries the signal and a second outer shield carries any RF pickup. The difference is that the outer shield is only connected at the source (i.e., low impedance) end of the cable making it directional. The intent is that RF noise is carried to ground far away from sensitive input circuits. Another one is like Audioquest's approach to as many as 5 shields with a resistive layer of material between them (rather than carry the signal away to ground, just turn it to heat).

 

DACs are notorious for radiating digital RF noise. One common occurrence is for the noise to travel out along the power cable and re-radiate from there. If this gets onto the interconnect sheilds and then into your power amplifier (which of course is setting right then next to your DAC), you can get intermodulation and other distortion artifacts showing up. If you put a more expensive power cord (which has a shield on it), the radiation from the power cord is reduced significantly and anything that makes it to the wall socket is now too small and too far away to affect anything. So GUESS WHAT? Putting a more expensive power cable on your DAC can actually make your Power amplifier or preamp SOUND BETTER. Go Figure!

 

- Jeff

 

P.S. The gain control on the back of the HDVD800 only affects the RCA unbalanced inputs to the amplifier section.

post #1115 of 2430

Someone should compare the 600 or 800 to the Lehmann Audio Black Cube Linear or Linear SE.  

Reply
post #1116 of 2430
Quote:
Originally Posted by GSARider View Post

So you don't have one and are definitely not buying an HDVD800 right? Time for you to post your V200 problems on the correct thread for them.wink.gif


My V200 is the only unit that I have faith in, and you can actually talk to the people at Mytek through Skype which helps.

Pretty darn good compared to Sennheiser, they respond to your emails after 4 weeks and their repair service doesn't really work either.

 

And no, I'm not getting anything made by Sennheiser again. The bad service, their BS marketing (which kinda started after I got HD 800s) and the price increase of the headphones (after I got them) make them seem like the next Apple to me. I might just get some Stax in the future when the HD 800s are getting old (or when they break again outside very bad 2 year warranty).

It's weird how a buddy of mine got 10 years warranty in the UK while I get only 2 years.

post #1117 of 2430

Time to move on then Melvin.
 

post #1118 of 2430
Quote:
Originally Posted by GSARider View Post

Time to move on then Melvin.
 


But Stax it too expensive, I'll move on later.

 

First world problems.

post #1119 of 2430
Some specification is already 'known, I read an article on this Italian magazine
There are photos of the interior of HDVD800 and some of the main components are:
  AD OP275, TI TPA6120; usb chip xmos.
I'm just a simple user, nothing to do with the magazine suono.it or sennheiser.
post #1120 of 2430

When  I finish the review I will have most of the specifications in the review.   I have been getting more information form Sennheiser and hope include all the specifications and working on finding out how they going to solve the issue. Stay tuned.

post #1121 of 2430

Because someone mentioned optical not supporting 192khz a few pages back I decided to try and see how my HDVD 800 would behave, and it goes up to 176khz here. When I play 192khz tracks it goes silent. I've tested all the other inputs as well and Coax, AES and USB supports up to 192khz.


Edited by TheManko - 6/24/13 at 10:03am
post #1122 of 2430
Quote:
Originally Posted by TheManko View Post

Because someone mentioned optical not supporting 192khz a few pages back I decided to try and see how my HDVD 800 would behave, and it goes up to 176khz here. When I play 192khz tracks it goes silent. I've tested all the other inputs as well and Coax, AES and USB supports up to 192khz.

 

When I first tried the TOSlink at 24/96 I would get this little "tick"  in the sound every few seconds. It was not regular, could vary from 2 to 30 seconds apart, but it was constant. I couldn't try anything higher because the basic optical out on the iMac was limited to 24/96. When I set it to 24/88.2, the ticking when away. It was then that I discovered the Caveat statement in the Instruction manual that came on the CD with the HDVD800 stating that the maximum speed for the optical was 24/88.2, so what I personally saw at least matched what the Instruction Manual said.

 

I noticed that on your original posting you edited your statement regarding the Coax, AES, and USB interfaces to remove the text saying that all 3 inputs showed the hissing artifacts on the C.C.Colletti tracks. Was this because you were correcting a mistake, or did you just think it wasn't pertinent to your posting? The reason I ask is that nobody yet has actually confirmed that the same issue can occur on all of the other digital interfaces. Have you actually seen the hiss issue on all of those interfaces?

 

- Jeff

post #1123 of 2430
Quote:
Originally Posted by wisemanja View Post

I noticed that on your original posting you edited your statement regarding the Coax, AES, and USB interfaces to remove the text saying that all 3 inputs showed the hissing artifacts on the C.C.Colletti tracks. Was this because you were correcting a mistake, or did you just think it wasn't pertinent to your posting? The reason I ask is that nobody yet has actually confirmed that the same issue can occur on all of the other digital interfaces. Have you actually seen the hiss issue on all of those interfaces?

 

- Jeff

It's because I thought it wasn't relevant to that point, but yes I have tested all the inputs with the C.C. Colletti tracks and they produce the same hissing. AES was tested via a V-Link 192, Coax and optical via a Xonar Essence ST.


Edited by TheManko - 6/24/13 at 11:45am
post #1124 of 2430
Hissing on all 3 inputs? Hmmm, I wasnt expecting that. USB, yes, but not coax... I was thinking that the problem was software based. It will be interesting to find out what the fix turns out to be. Im guessing a firmware update from Sennheiser now.
post #1125 of 2430
Quote:
Originally Posted by palmfish View Post

Hissing on all 3 inputs? Hmmm, I wasnt expecting that. USB, yes, but not coax... I was thinking that the problem was software based. It will be interesting to find out what the fix turns out to be. Im guessing a firmware update from Sennheiser now.

Ultimately, it's the same audio data stream that gets processed regardless of which input it comes in on. Initially I could only check out the USB input and from all initial reports it seemed to be transfer mode related. However, we then were hearing of folks using different transfer modes that were getting the hiss as well. From that, I later suspected that all inputs would produce the same results.

 

Passing an audio track with an exceptionally high amount of ultrasonic content in a bit perfect fashion to the HDVD800 creates the problem regardless of which digital input it comes in on. The problem is how the HDVD800 handles flakey data (or rather how it doesn't handle it), not so much how it gets into the product. The initial red herring that threw me was I got the problem with BitPerfect running and not when it was disabled. When BitPerfect was disabled, the audio data was running through iTunes CoreAudio which does processing on the data. Somewhere in there it is probably running the data through a digital low pass filter and thus chopping off all of the ultrasonic stuff.

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