Nice review, thanks

In my humble opinion, TheManko has nailed it here and I agree completely. One thing that does need to be pointed out though (again another issue with the digital section) is that this product is advertised as supporting 24/192 sample rates on all of the digital inputs. This is not the case. On at least one of the S/PDIF interfaces -- the TOSlink -- you cannot run over 24/88.6 without sound degradation and clicking. In fact, as far as I've been able to discern, this speed limitation is documented only in the user manual that you get with the product, but not in any advertising literature on the product, even on Sennheiser's website.
 
Also, versions of this product with firmware at the 1.03version level may exhibit what appears to be severe aliasing noise if the audio file  being played has a lot of ultrasonic noise in it (yet another issue with the digital section). A firmware patch to bring the version to 1.04 which fixes this is available from Sennheiser.

Very nice!!

Thanks everyone. Good points by Wisemanja, it's a bit odd how there's obvious typos of the product description on the homepage that hasn't been corrected since the HDVD 800 was released. The correct info is there in the manual .pdf download, and I've tested the Toslink input and confirmed that the info in the manual is correct. The website info is incorrect.

Good to hear this, and good to hear the HDVA600 is a nice match without the Dac 

Very informative review. Thank you.

Great honest review, coming from the Asus essence one with muses myself now sold. My impression echo yours, very happy with the amp section. The DAC does leave a little to be desired no doubt but for an all in one solution it's a beautiful package. I move on to a PerfectWave DAC now and absolutely live the combo. Thanks for the excellent write up.

WOW thanks for your info guys. I almost pulled the trigger on this at amazon for $1500 but i was not in the mood for an inferior DAC. I will wait for a sale on the HDDVD600 and get a separate professional DAC. Thanks Again.

I disagree with the inferior DAC review. Unless the Benchmark DAC2HGC is a total piece of crap. It is compared to the HDCD800 in my many hours of listening tests. Benchmark is parked for this application for now. It is a $2000 piece. The HDCD is not a midlevel DAC! I do admit that I did all this listening with carefully recorded high quality classical recordings. Maybe that is not the material to use for this type of comparison.

Hello. You mentioned that the sennheiser amp made your audeze lcd 2 sound good. As i am looking to get this combination please could you elaborate on this.

It’s been a while since I wrote the review, and since then I’ve spent plenty of time using the HDVD 800 with the LCD-2 and LCD-X. If you’re primarily using low impedance headphones like the Audeze models, then I would advice against getting the HDVD 800. I mentioned in the review that the impedance mismatch between the LCD-2 and HDVD 800 shouldn’t adversely affect the frequency response of the headphones. But from experience I’ve noticed the effect is clearly audible.
 
What happens when you use Audeze headphones with the HDVD 800 is that the sound becomes “peaky”. There’s more midbass, and the midrange sounds a bit uneven. The typical Audeze sound is flat and controlled in a restrained manner. With the HDVD 800 that character changes into a more out of control “in your face” type of sound, and the deep bass gets lost because of the mid bass peak. It doesn’t sound bad, but it doesn’t sound like how Audeze intended their headphones to sound. It’s an unfortunate side effect of how Sennheiser designed the amplifier. They optimized it for high impedance headphones like the HD 800, and if you want your LCD-2 to sound their absolute best this amp won’t do it. They’ll sound good! Just not how they were intended to sound.

Thank you for the advice. Unfortunately I have already order the sennheiser HDVA 600. My Dac is the audiolab MDAC. Do you think this amp Dac combo may sound better with the lcd 2? I could also perhaps change the cable to a balanced silver cable for more higher frequency extension and balance?

I haven’t heard that dac, so it’s certainly possible it might sound really good with the LCD-2 and HDVA 600. Only way to know is to hear it. I don’t have the LCD-2 anymore, but when I did I compared it using the Violectric V200, SPL Auditor and HDVD 800. I preferred how it sounded with the HDVD 800 over the two other amps, as they have their weaknesses which did more to harm the sound than the negatives of the HDVD 800 did. I expect you’ll find it sounds great. 
 
Getting a balanced cable certainly makes sense since it’s a balanced amp. All the LCD series headphones use the same connector, so if you in the future change to a different model it’s still usable. As for make and model of the cable, I have limited experience personally. When I bought a balanced cable for my LCD-2 I went with the Q Audio Cable, because I wanted something light. I felt the weight of the standard cable was bugging me as I could feel it weighing down the headphones. That was what I prioritized at that time. I can’t really say which cable would be the best in your case.

Hi theManko I just wanted to update you on the amp. I received it yesterday and let it burn in for around 10 hours. I have to say it sounds epic. The audilab MDAC compliments the HDVA 600 perfectly. The sound is very controlled and with amazing dynamics, bass and even treble sparkle from the Audeze lcd 2. It surprisingly blends together seamlessly. this will be my setup done. Except for cable upgrades of course.

One strange thing that boggles my mind is that the sennheiser hdva600 is not very heavy and after seeing pictures of the circuit board you realise there is no traditional chunky toroidal transformer. I wonder how it manages to produce such precision without a chunky power supply. Perhaps you can educate me.

Glad to hear it! Regrettably I don't know enough about amplifiers to tell you the how and what behind the HDVA 600 design compared to other amps.

I auditioned this amp/dac combo recently and your title sums it up correctly.  IMO, Sennheiser should have place a much better DAC inside this statement piece.  The amp section is really well done sadly the DAC really make this amp sound bright, thin, and lack dimensional.  Using an outboard DAC (NAD M51), this amp is within the striking distance of statement amp such as the Headamp GS-X MKII.
 
I would just get the HDVA 600 instead of the HDVD 800 and spend money on a better DAC.

A silly question needs confirmation: if I connect another DAC to HDVD800 and select that source as input, the built-in DAC on HDVD800 would be completely cut out and won't affect the amp' performance in anyway, right?

Yes, when you switch to the external inputs the HDVD 800 makes audible clicks as the relay switch changes from the dac to the external rca or xlr inputs. At that point the dac isn't involved at all. A while back I had the HDVD 800 dac connected to a computer that was transmitting all sorts of electrical noise out its USB ports. When I turned the dial from the dac inputs to the external inputs the noise disappeared, confirming that the rca and xlr inputs are truly independent, with no noise bleeding across to them.

Given what you say, would the Hugo be a better one-box solution then?  Is it likely Sennheiser will upgrade the HDVD800 with a better DAC any time soon?  Thanks.