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Sennheiser HDVD800 Headphone Amplifier - Page 76

post #1126 of 2149

I got an email form Axel Grell today and he has been giving me most of the specifications for my review. He will give me all the power ratings also.  He also told me that the hissing issue will be fixed with a firmware solution that they are working on now.   I expect that they will be making a post here sooner or later  but they are working  o correcting the hissing issue and will get it resolved.


Edited by Frank I - 6/24/13 at 1:53pm
post #1127 of 2149
Quote:
Originally Posted by wisemanja View Post

 

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

Jeff the hissing is not happening on all digital interfaces. My brothers vivaldi system has no hiss nor does my Oppo. It will be fixed by firmware according to Axel Grell email to me today.

post #1128 of 2149

well, do they give you a deadline for the fix?

about 10% of my music from HDtracks are not listenable~~~~

This is very very sad to me~~~~~

post #1129 of 2149
Quote:
Originally Posted by Frank I View Post

Jeff the hissing is not happening on all digital interfaces. My brothers vivaldi system has no hiss nor does my Oppo. It will be fixed by firmware according to Axel Grell email to me today.

 

Hi Frank. Thanks so much for the updates!

 

With them being able to perform a fix via firmware, I'll bet that they are just adding some kind of digital anti-aliasing filter which should do the job nicely! (I'd bet dollars to doughnuts that it is basically a function that the Oppo and Vivaldi, as well as others, already have built in)

 

And as long as the firmware can keep up with the bit rates involved, the sonic signature of the unit shouldn't change. In fact, if there is any non-linearities in the upper range of the analog stage, removal of the ultrasonics could also remove intermodulation distortion artifacts that might exist as well.

 

- Jeff

post #1130 of 2149
Good news and great to see Axel moving quickly on this.
post #1131 of 2149

I will keep posting any more information that they give me but it all sound like they can fix it easily. 

post #1132 of 2149
Quote:
Originally Posted by wisemanja View Post

Hi Frank. Thanks so much for the updates!

With them being able to perform a fix via firmware, I'll bet that they are just adding some kind of digital anti-aliasing filter which should do the job nicely! (I'd bet dollars to doughnuts that it is basically a function that the Oppo and Vivaldi, as well as others, already have built in)

And as long as the firmware can keep up with the bit rates involved, the sonic signature of the unit shouldn't change. In fact, if there is any non-linearities in the upper range of the analog stage, removal of the ultrasonics could also remove intermodulation distortion artifacts that might exist as well.

- Jeff

I agree I read a paper that indicated (if I understand it correctly and can paraphrase here) that if the amplifier is able to reproduce these ultrasonic frequencies, then it must expend power to do so, which could introduce audible distorion. Filtering these frequencies eliminates the problem.
post #1133 of 2149
Quote:
Originally Posted by palmfish View Post


I agree I read a paper that indicated (if I understand it correctly and can paraphrase here) that if the amplifier is able to reproduce these ultrasonic frequencies, then it must expend power to do so, which could introduce audible distorion. Filtering these frequencies eliminates the problem.

 

That is part of it. The issue is that as you approach the bandwidth limits of an audio amplifier, it can become non-linear and intermodulation distortion occurs. If ultrasonic noise frequency #1 and ultrasonic noise frequency #2 are close together (let's say 900 Hz) and in the non-linear bandwidth of the amplifier, you will get (among other artifacts) a 900hz signal that is the difference between noise #1 and noise #2. If the ultrasonic noise was white noise, Even the intermodulation difference artifacts alone could be limitless.

 

But remember, these artifacts are not necessarily the same as the aliasing artifacts that can come from running data that is higher than the Nyquist frequency through the conversion algorithms. These aliasing artifacts can be much louder than the intermodulation artifacts. So if you eliminate (i.e., filter out) the data creating the aliases during conversion, it can have the side benefit of reducing the audio components that can create intermodulation artifacts in the non-linear sections of an analog amplifier as well.

 

In general, having large amounts of ultrasonic/Radio frequency energy inside an audio amplifier will definitely cause trouble, and in some cases, damage (imagine high levels of ultrasonic sound going through your amplifier to the tweeter of a speaker system. Even though you couldn't hear it, it could still burn out the tweeter itself). That's why they build these things inside of metal boxes that USUALLY don't have holes in the top of them for inspection ports smile.gif

 

My present thoughts are that the hiss is primarily alias energy with a bit of IM thrown in. An anti-alias filter removes the ultrasonics that creates the aliases.

 

Again I only know enough to be dangerous here, but i hope these descriptions are of some use to others in the forum. redface.gif

 

- Jeff


Edited by wisemanja - 6/24/13 at 9:44pm
post #1134 of 2149
Quote:
Originally Posted by Frank I View Post

I got an email form Axel Grell today and he has been giving me most of the specifications for my review. He will give me all the power ratings also.  He also told me that the hissing issue will be fixed with a firmware solution that they are working on now.   I expect that they will be making a post here sooner or later  but they are working  o correcting the hissing issue and will get it resolved.

 

Not being the most technical guy around, rather the opposite (especially in this thread...), I ask myself how can i get a new firmware into my HDVD 800 once it is available? Anyone care to explain? Thanks!
post #1135 of 2149

Yes, we're in the midst of developing the firmware for the HDVD 800. It will include a launcher and work on both PC and Mac platforms. Once ready, we'll make an announcement and put up a link for download on our website. Thank you for your patience and understanding as our team work on this fix.

 

Rosmadi

 

Quote:
Originally Posted by uffeolby View Post

 

Not being the most technical guy around, rather the opposite (especially in this thread...), I ask myself how can i get a new firmware into my HDVD 800 once it is available? Anyone care to explain?Thanks!
post #1136 of 2149
Quote:
Originally Posted by MelvinV View Post


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.
So what exactly happened to your HD800's...?
post #1137 of 2149

If everything goes as I hope, I will receive my HD + HDVD 800 next week (friday) or the week after that.

I can't wait, but I'm also a bit nervous :) (it isn't cheap). And it is a demo model, so alot cheaper than otherwise but still alot of money.

Does anybody have experience (good or bad) with demo models (not for demo use but actually buying it)?

I have about 2 weeks to deside and get 2 years guerantee.

 

I'm gonna thoroughly test it with games, movies and music.

Is a balanced cable worth the money? What kind of difference can you expact?

Thanks

post #1138 of 2149
Quote:
Originally Posted by Rosmadi Mahmood View Post

Yes, we're in the midst of developing the firmware for the HDVD 800. It will include a launcher and work on both PC and Mac platforms. Once ready, we'll make an announcement and put up a link for download on our website. Thank you for your patience and understanding as our team work on this fix.

 

Rosmadi

 


And I trust it will support Mac...good news that it's being dealt with.

post #1139 of 2149
Quote:
Originally Posted by BlancoTheBull View Post

And it is a demo model, so alot cheaper than otherwise but still alot of money.

Does anybody have experience (good or bad) with demo models (not for demo use but actually buying it)?

 

Is a balanced cable worth the money? What kind of difference can you expact?

Thanks

Mine was a demo model as well since the store I bought it at had run out of stock. The condition will of course vary, but generally it's just fingerprints and dust. Amps like the HDVD 800 aren't subjected to the horrors of something like the Best Buy speaker section where every tweeter has been pushed in by kids. Just wipe it off and it will hopefully look like new, unless the store already did that for you.

 

As for balanced cabling it's taken forever for my cables to arrive. Ordered one for the HD 800 and another for the LCD-2 back in May and it looks like they'll be shipped any day now. I'm anxious to find out just what the difference will be as the balanced ports have been staring at me every day for months now, waiting to be used.

post #1140 of 2149

Fellas, everyone has a right to an opinion. I think the HDVA600 is a superb amplifier (and yes, I do own one even if I don't use possesive pronouns like "my" or "mine", that I leave to our American friends here), just not as good as it could have been. What we need are the reviews, be it positive or negative reviews. At 1600 Euro, it is a bit expensive and the HDVD800 is simply too much at 2000 Euro.

 

I will agree that it is difficult to make judgements based on short-term experience but there are those that can say quite a lot about something if they are professionally qualified in that regard. So one doesn't always have to, in this case, listen to something to be able to say something constructive. After all, if I am a bridge designer who has never walked across some bridge, I would still be able to say a lot more about that that bridge than someone who walked across it thousand times but knows nothing about bridge design. I am quite sure there are people like that on this forum so one doesn't need to insist on listening first and then commenting. It is ridiculous and completely unfounded.

 

As for the output impedance, I seriously doubt it is 43 Ohm. Nothing is known about this amplifier and the published specifications are vague at best. The noise that some have reported might be due to the fully balanced circuit design which, while a noble idea, often doesn't work like intended. The hassle is zero rejection to common noise which means the noise is only amplified once it enters the stage. The other, more serious problem, is component matching because, and let's not forget, fully balanced means twice as many components. Those components have to be symmetrically matched and this includes both passive and active components. Anything short of that would nullify the advantage of such a layout and in every other case, differential circuit is the better solution. There is a good reason why best tube amplifiers are never balanced and no serious DIYer / tube enthusiast would ever consider such a topology. One might be smart here and say that we're not talking about tubes here and that's correct, we are not. But tubes, because of their inherent disadvantages and originally intended application, serve as a good example why component matching is critical in a fully balanced design.

 

What I would be interested in seeing are measurements - real life measurements of the D/A converter stage on line outputs. I'd like to see measurements of the amplifier section as well - IMD numbers, linearity and crosstalk at 20kHz (I suspect it is 80 dB at best).

 

I have respect for Sennheiser and my experience is that they make things that work and continue to work for years. Even if they could have done a better job with the amplifier, I think it is a worthy addition to their portfolio and I am convinced that future versions (or even revisions) will be better.

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