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Sennheiser HDVD800 Headphone Amplifier - Page 81

post #1201 of 2367

After much searching, the one and only picture of the inside of the HDVD800 that I could find...

 


Edited by palmfish - 7/9/13 at 10:46pm
post #1202 of 2367
Quote:

Originally Posted by wisemanja View Post

[snip...]

 

By the way, I still have not determined whether or not the HDVD800 is fully balanced all the way through the DAC section as well. I.e., in addition to the 4 internal amps (2 for each balanced channel) there would be 4 DACs as well. I.e., 2 DACS for the left channel and 2 for the right. One DAC would handle the normal signal and one would handle the inverted signal for a given channel. These would each feed independently to the inverted and non-inverted amps for the output to the headphones.

 

The Burr Browm PCM1792 (which is has been reported to be in this product) is a stereo DAC, so only 2 parts would be needed.

post #1203 of 2367
Quote:
Originally Posted by wisemanja View Post

 

...the slew rate doubles. Given that a single amp can change it's signal output at a given rate, connecting the second inverted amp results in the inverted signal moving away from the non inverted signal at twice the speed as a single amp's output by itself. The results are a much quicker amp which can improve openess.

 

 

The electrical demands of driving a pair of headphones to an amplifier is about the same as you lifting an 8 oz cup of coffee up off the table. Having two amps sounds great in theory, but in the real world, you will be able to drink your coffee without breaking a sweat.

post #1204 of 2367

Here's a good discussion on balanced headphone amplifiers...

 

http://www.amb.org/forum/benchmark-engineer-on-balanced-v-unbalanced-headphone-amps-t326.html

post #1205 of 2367
Quote:
Originally Posted by murrays View Post

 

The Burr Browm PCM1792 (which is has been reported to be in this product) is a stereo DAC, so only 2 parts would be needed.

 

Oh yea. The Burr Brown PCM1792 has dual differential outputs so it is balanced output by default.

post #1206 of 2367
Quote:
Originally Posted by palmfish View Post

Here's a good discussion on balanced headphone amplifiers...

 

http://www.amb.org/forum/benchmark-engineer-on-balanced-v-unbalanced-headphone-amps-t326.html

Make sure to follow most of the thread though. The initial commentary seems a little partial and doesn't cover some other pertinent details. For example, going to a balanced configuration will double the output impedance of the amp, but what if that impedance is only 1 ohm (or less) to start with? Using 300 or 600 ohm headphones are still going to result in the damping factor being huge.

 

And of course the proof's in the pudding. The HDVD800 sounds much better when used in balanced mode--at least that seems to be the case with my T1.

post #1207 of 2367

Yes, I agree. All 4 pages of the discussion are worth reading, and good points are made on the pros and cons. Personally, I think Solude's quote (page 3) summed it up best:

 

"BM is overstating the downsides in relation to the B22 and AMB is overstating the benefits in relation to the B22. Ie the B22 output impedance is so low doubling it is still 0 ohm and since parts matching is to be expected, no increase in noise. But on the other side AMB's listed benefits aren't problems the B22 suffers from. Ie B22 is already silly powerful, doesn't have noise worth cancelling and its slew rate is multiples of whats needed for audio at its rated output."

 

As for the balanced output sounding better, what can I say? People claim subjective audible improvements for power cables, audiophile fuses, pointy brass feet, and green magic markers too. But that's a discussion for another thread... wink.gif


Edited by palmfish - 7/10/13 at 7:59am
post #1208 of 2367

Anyways, I'm not knowledgeable enough to assess the photo I posted above, but maybe someone here knows enough about amplifier PCB's to look at the opamps and caps and tell us if it is fully balanced?

post #1209 of 2367
Quote:
Originally Posted by palmfish View Post

Anyways, I'm not knowledgeable enough to assess the photo I posted above, but maybe someone here knows enough about amplifier PCB's to look at the opamps and caps and tell us if it is fully balanced?

seems it is fully balanced, at least we can clearly see there are 2 pairs of symmetric path leading to the single end and balanced output.

post #1210 of 2367

I had a Violectric V200 & V800 before and there's a number of tweaks related to them (ground lift, DC coupled volume control, gain settings etc) that make differences so small that they fall within the realm that it could be the users imagination creating the difference. I was worried that going balanced with the HDVD 800 would produce similarly small gains, but as it turns out the difference was big enough that there's no doubt it sounds better.

post #1211 of 2367
Quote:
Originally Posted by TheManko View Post

I had a Violectric V200 & V800 before and there's a number of tweaks related to them (ground lift, DC coupled volume control, gain settings etc) that make differences so small that they fall within the realm that it could be the users imagination creating the difference. I was worried that going balanced with the HDVD 800 would produce similarly small gains, but as it turns out the difference was big enough that there's no doubt it sounds better.

At least on HDVD800, the Balance output is better than the single ended. The difference is much bigger than switching wires or changing between two very high end SSD dacs~~~~ You can hear it for sure.

 

Either they made the single ended output very bad, or balance in general gives more control form the amp to the headphone because the "Push and Pull" on both porlialtry

post #1212 of 2367

Yesterday I received Senn HDVD 800 and HD 800 (not balanced 'yet' :)). Not at all what I heard in the store (now its digital, in the store it was CD player).

Less of everything (soundstage, headstage, detail, openness/airyness, clearness).

It sounds almost identical to my HD598 with Fiio E17, wich shouln't be the case :). I think only a 10% improvement, so somewhere there's a big bottleneck.

 

I'm listening with a external HDD usb cable (direct from usb out of mobo, music from different hdd's (no difference)), what are peoples experiences with better usb cables? I know that experiece/thoughts are very varied.

What are benefits that you can clearly hear with better usb cable? Wich cable do people recommend? Or wich cables are used? I know about audioquest and some others, but never heard any.

 

Are there other improvements I can make? I already tried some stuff with foobar (like PPHS (tried 196000, now 96000) and kernel component (now 24 bit)), I thought it was a slight improvement.

But I really think there is a big bottleneck somewhere (because I already heard this set and it sounded unbelievable (soundstage etc) compared to what I'm hearing now).

 

A store is offering me a cable 'Heavens Gate USB cable, Ultra Supreme, 1 metre. Pure Silver' from 999 for 325, anyone any experience with this cable?

 

Thanks alot for all thoughts/help/sharing experiences etc.

 

Btw I hear alot of noise with some songs, almost always when it's a song where I have to turn the volume up quite a bit (from 1/4 to 1/2 of total volume). And I don't have 24/196, so it's 24/96 or lower "quality". Perhaps usb or some upsampling setting to 24/196 perhaps? I'm sorry for my English and the fact that I don't know anything about audio. But I try :)

post #1213 of 2367
Quote:
Originally Posted by AlanHell View Post

Either they made the single ended output very bad, or balance in general gives more control form the amp to the headphone because the "Push and Pull" on both porlialtry

Probably the first thing.

post #1214 of 2367
Was the one in the store balanced? Keep in mind it's brand new and needs 150-200hrs to wear-in.
post #1215 of 2367

In store wasn't balanced. What I have is exactly what I listened to in store (demo model). Only difference is that there I listened through CD, and now only digital (DAC).

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