As promised, here are my impressions of the Sennheiser HDVA600. There are few things you have to keep in mind though. As an audiophile, my approach to audio is derived from my music background and realism is what I value the most. Everyone knows that even studio masters are not the real thing but only an opinion on how it should sound. It is an opinion of the recording engineer for the most part. That is why my reference recordings are studio recordings I did years ago. I played in the orchestra, I was in the recording room when the mix was done and now in front of the speakers, or rather, headphones!
This approach might not be everyone's vision of audio nirvana but it is for me. So, without further adue, let's get to it!
Frequency response & balance
Straight out, the response seemed pretty extended to me. The acoustic bass was rendered very nicely with plenty room to breath and with no restrictions in the bottom end. Full draw church organ seemed pretty powerful to me with no colouration and depth seemed pretty realistic to me. Mid frequencies were equally good even though this is something I expected. National folk string instruments sounded as realistic as I have heard them. Equally good were the vocal choirs. High end sounded pretty good too. It was smooth and well integrated into the lower parts of the spectrum. However, I did notice a certain amount of grain in symphony strings. It was given away with slight edginess around the notes but I didn't feel like it was a serious problem. All in all, the response is above average with excellent low end and mid range while the high end lacks a little bit of refinement and polishing. Response integration and uniformity was very good to excellent. Certainly above average but not the best I've heard. I give it an 8 out of 10.
Dynamics, attack & decay
Dynamics is an extraordinarily importanct criteria and the amplifier performed well in this regard. Symphony orchestra sounded very articulate and dynamically correct. Macro dynamics was excellent and the amplifier seemed to have no problems providing full scope of dynamics, from intermittent accents of the front row instruments to huge orchestral parts with cymbals. Very nice indeed. Japanese traditional drums sounded powerful and yet never out of control. They are not overly musical in my opinion but they do present quite a strain on amplification. However, micro dynamics was not as convincing. Everything was there but it wasn't as obvious as I would have liked it to be. The natural timbre of a national string instrument (known as „pearls“) was reproduced in a manner that seemed to limit the instrument's resonance. In a way, it sounded a bit more sterile or dry as some would put it. It seemed as though the amplifier was very controlled in it's presentation and I would agree with that but still, the instruments didn't sound as realistic as I've heard them. As far as symphony instruments go, they were reproduced pretty well and due to their inherent design and playing technique, this flaw was not as obvious. Full scope dynamics attack was very good like the macro dynamics. Small deviations in volume were rendered well and generally, this amplifier had the ability to surprise me. Decay seemed to have been controlled so each note ended when it supposed to, not sooner and not after. Piano ambient music revealed a very textured decay so this, in my view, compensates for the lack of micro dynamics and I give this amplifier an 8 out of 10.
Micro dynamics and detail resolution breathe as one even though there are some discerning differences. Overall, the amplifier was pretty detailed with lots of low level detail that made the session worthwhile. We are way beyond simple string plucks here and in the realm where air conditiong that was operating during the live session gets in the way. So yes, I'd say this amplifier is very detailed in it's presentation. Still, the aforementioned grain in the high end made things a bit difficult and in certain cases the amplifier seemed to have produced details that weren't really there. I couldn't discriminate these features as instrument properties, moving of the musician's chair or turning the page of the music book on the stand. In a way, it was a bit translucent but not in a way where I would say it had a bit of sparkle because it wasn't detail that was on the recording. Still, this isn't a serious problem by any means. Once again, I give it an 8 out of 10.
Spatial imaging & sound stage
As expected, sound stage was very good. The width seemed realistic and so did the height. The depth, however, was not always as transparent as I would have liked it to be. Of course, there's only a hanful of recordings with realistically recorded sound stage so this should not be a problem for the most part. Still, reference recordings reveal a somewhat dense structure where there is less space between the front and back row of musicians. Good detail resolution as well as dynamics allowed for good instrument placement accuracy so there were no problems there. If the sound stage was deeper, it would have allowed for more air between individual instruments and it would undoubtedly improve the micro dynamics. But as it is, it is really not bad at all. Imaging left something to be desired however. There was no diffused field however and the image was well laid out and coherent with most recordings. However, electronic instruments with lots of channel panning did seem to be lower in volume once they were in the center of the image. Obviously, the image was not spherical enough to allow for better imaging. There is a certain sound effect that simulates fireworks where you have this rocket that goes up in the sky, explodes into several pieces and then you can follow the trajectory of each individual piece. Very attractive indeed and it was rendered rather well so I would say it still has good imaging and that is why I give it a 7 out of 10.
Build quality & ease of use
It is a straightforward amplifier and as such, it is simple to use. The power on/off switch is a sensory type with a blue LED ring around it. The volume control potentiometer is very nice and smooth as is the rotary input selector switch on the front. Headphone output connectors on the front panel are of good quality and so are the ones on the back panel. However, at this price point I find the cheap RCA connetors unacceptable. This is a headphone amplifier and as such it is bound to be disconnected, moved and reconnected more than a couple of times. Even though these conntectors would withstand a bit of that, much nicer ones would have been appreciated and not nearly as expensive as the glass covered top. One interesting detail is the volume control shaft. Apparently, the potentiometer on the front panel is hooked up to a long shaft that goes half way into the chassis and this is where the actual attenuator is located. Clearly, some effort has gone into making the signal path shorter. It's a nice touch and in the days of high fidelity mayham in the late seventies and early eighties Sony used to use this principle for almost all switches on their higher end components. Finish is first class as expected. If not for those cheap connectors on the back, I would have given it a pure 10 but as it is, it only gets an 8.
Value for money
At 1600 Euro in Croatia and most parts of Europe, this is not at all a cheap amplifier. It does offer a pretty high level of performance for the money but competition is more than stiff. It is one of the most expensive solid state amplifiers available in this part of the world. The conclusion is then, the Sennheiser delivers but not to a point where someone should buy it without taking a good listen at the competition. From a perspective of audio technology, this is a nice piece that will appeal to many I am sure and one day might prove to be quite a valuable piece since we don't know how many they are planning on producing.
Headphones used: Sennheiser HD800 and HD650, Beyerdynamit T1, highly modified AKG K240DF (used only to verify the response balance)
Transport: modified Denon DCD-1520 (Sony KSS-151)
D/A converter: reference triode DAC ver. 1.1. (based on a single 6H30 fed directly off CS4398's pins, no output filter, Mundorf silver/gold/oil throughout, Holco 1% resistors)
If anyone is interested in hearing how the HDVA600 pairs with HD650, let me know. The amplifier was tested using the HD800 for the most part with some excursions with the T1.
Edited by R Giskard - 1/6/13 at 6:46am