Sennheiser HDVD800 Headphone Amplifier
Jun 28, 2013 at 10:19 AM Post #1,156 of 3,016
it was really nice of Mr. Grell to provide some detailed specs. The 43 Ohm impedance is a curiosity and in the end, I am relieved because it suggests minimum compromise in the circuit design (less feedback) even if that means incompatibility with lower impedance headphones.
 
When I said that -600 amp is a better value than the -800 model, I was referring to the prices here and for the 400 Euro difference, better DACs can be had though the combination may not be as compact.
 
Jun 28, 2013 at 11:49 AM Post #1,157 of 3,016
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get-attachment.aspx
 
 
 
Axel Grell sent me these power rating for my review. Very impressive numbers for a headphone amplifier for power. These will be published on the sennheiser website but I got permission to use the numbers here. 
 
Jun 28, 2013 at 12:46 PM Post #1,159 of 3,016
weird I can see the images on my screen here. 
 
 
ohm                      Power in Watts
 
 
16                        2.64
18                        2.72
32                        2.76
51                        2.50               
64                        2.33
150                      1.56
300                      0.96
600                      0.54
 
Jun 28, 2013 at 1:30 PM Post #1,162 of 3,016
Quote:
This is  from Axel Grell regarding some of the questions I had asked and his response from the Project manager himself regarding some design questions and  the output impedance which he told me was 43 ohms.
 
 
 
[size=small]nced amplifier. The information that has been released so far is very vague. Is the USB a aschronyous design or it is not.[/size] 
[size=x-small]** It is an asychronyous design using a xmos processor.[/size] 
[size=small] Other questions  I need for my review include the empower rating for the amplifier. How much power does it put into 32ohms,50ohms, and higher inputs like 300 ohms and 600 ohms.How many amplifiers are used in the hdvd800?  [/size] 
[size=x-small]** The output power into 600ohms is 480mW. The values for 32ohms, 64ohms, 150ohms and 300ohms will be available tomorrow. There are 4 amplifiers in the HDVD 800.[/size]

[size=small]What is the input impedance of the amplifier.[/size] 
[size=x-small]** It is 10k for the RCA input and 20k for the XLR input. The output impedance is 43ohms.[/size] 

[size=small] Internet articles from the Munich show suggested it was 43 ohms. Can you verify what all the specifications are?  People are concerned about the DAC issue. I have tried high resolution files from three or four vendors all different and mostly 24-176.4 DSD files and others up to 24-192 hz and they all are hissing and not playable. What is being done to fix this problem?.  Potential customers want to know why this problem is occurring on the hDVD800 DAC and not on other DAC's. My Oppo BDP 105 sailed through all the same files.. [/size]
[size=x-small]** We have tested HDVD 800 carefully before we relesed to the market. With the files we have used and the measurement equipment we never found this behaviour. But now customers send us 24-192kHz files wich produce a lot of noise with the HDVD 800. We have analyzed the files and found they contain a lot of hiss in the inaudible range close to the half of the sampling frequency. We are working on a new firmware that will solve this problem.[/size]


Great info, a couple of questions, sorry if that was addressed already earlier, it's a big thread to swim through.
- Does it support DSD (guess not but you mentioned some DSD files you played)
- And is amp section discrete or opamp design.
 
Jun 28, 2013 at 2:07 PM Post #1,163 of 3,016
Quote:
Great info, a couple of questions, sorry if that was addressed already earlier, it's a big thread to swim through.
- Does it support DSD (guess not but you mentioned some DSD files you played)
- And is amp section discrete or opamp design.


If they throw opamp into HDVD800, I will refund my money right away man~~~~~~~~
I am more curious about the solid state power supply~~~~ 
 
P.S.
Does anyone know someone on this planet  is crazy enough to open it up and post some pictures?\
 
Jun 28, 2013 at 2:34 PM Post #1,165 of 3,016
Well,  I get it when they use opamp for portable devices. They need the space and power efficiency.
But a balanced desktop amplifier with what they claimed to have "four amps", putting opamp inside is like scamming~~~~~
If the amp section is not fully discrete, that just means their R&D department in the past few years are doing nothing but writing essays and sendin them to the marketing department for BS. I am sure for a big company like Sennheiser, this will not happen.
 
 
P.S.
I never used the amp on my dac before, and will never use them in the near future~~~~
 
Jun 28, 2013 at 2:39 PM Post #1,166 of 3,016
Well,  I get it when they use opamp for portable devices. They need the space and power efficiency.
But a balanced desktop amplifier with what they claimed to have "four amps", putting opamp inside is like scamming~~~~~
If the amp section is not fully discrete, that just means their R&D department in the past few years are doing nothing but writing essays and sendin them to the marketing department for BS. I am sure for a big company like Sennheiser, this will not happen.


P.S.
I never used the amp on my dac before, and will never use them in the near future~~~~


You use the amp in your DAC everytime you send an analog signal from your DAC1 to your headphone amplifier.
 
Jun 28, 2013 at 4:13 PM Post #1,168 of 3,016
Quote:
Well,  I get it when they use opamp for portable devices. They need the space and power efficiency.
But a balanced desktop amplifier with what they claimed to have "four amps", putting opamp inside is like scamming~~~~~
If the amp section is not fully discrete, that just means their R&D department in the past few years are doing nothing but writing essays and sendin them to the marketing department for BS. I am sure for a big company like Sennheiser, this will not happen.
 
 
P.S.
I never used the amp on my dac before, and will never use them in the near future~~~~

Well...I'm a huge fan of a discrete design but a really good op-amp designed can sound pretty remarkable as well.  The April Eximus DP-1 also use op-amps on the DAC section and it sounds drastically more musical than the W4S DAC2.  The W4S's output stage is all discrete.
 
Jun 28, 2013 at 5:20 PM Post #1,169 of 3,016
Quote:
Great info, a couple of questions, sorry if that was addressed already earlier, it's a big thread to swim through.
- Does it support DSD (guess not but you mentioned some DSD files you played)
- And is amp section discrete or opamp design.

Roght now the dsd files are down sampled to 176.4 and no USB dac to my knowledge can play a dsd file through the USB without converting it to PCM. The DAC on the HDvd800 is hissing and noisy with all my DSD files. The firmware fix should address that.
 
Jun 28, 2013 at 5:22 PM Post #1,170 of 3,016
Quote:
Well,  I get it when they use opamp for portable devices. They need the space and power efficiency.
But a balanced desktop amplifier with what they claimed to have "four amps", putting opamp inside is like scamming~~~~~
If the amp section is not fully discrete, that just means their R&D department in the past few years are doing nothing but writing essays and sendin them to the marketing department for BS. I am sure for a big company like Sennheiser, this will not happen.
 
 
P.S.
I never used the amp on my dac before, and will never use them in the near future~~~~

The hdvd800 is an op-amp design.   
 

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