In a relatively short time Hegel gained the status of the audiophile brand. It would seem that designing a big amplifier with shiny tubes and bright power meters is the best way to enter the market in such a spectacular way, but it's not the only one. It is hard to deny that many people still buy audio gear with their eyes, and the thickness of the wallet doesn't always go hand in hand with good taste. Norwegian devices have always been extremely modest. Matt fronts with at most two knobs and display do not promise anything revolutionary. But remember that sometimes the inside of device is the most important part.
Hegel has some interesting technical solutions, highly refined electronics and philosophy which assumes that technological advances should affort for creating better and cheaper products. This was true with the HD11 DAC, which according to many is clearly better than its predecessor, but much cheaper. You can say the same about the H80 amplifier, which costs only a few hundred dollars more than the H70, but it has a built-in DAC with lots of digital inputs and it shares the preamp elements with the top H300 integrated amp. Is HD25 as good investment as these devices?
Design and functionality
I remember when this model appeared on the market. Based on the external appearance some people have stated very fast that the HD25 is exactly the same as the HD11 model only with better parts inside and a small gadget - the front wall, which is also the input selector. Clever and functional solution, but the cost calmed the appetite for this new model - twice the price of the HD11. If the flagship DAC had been packed in the enclosure copied directly from the H80 amplifier, probably no one would have objected. Norwegian engineers knew that there is no need to put circuit boards in the larger housing just to get attention of a few people. So the HD25 got the same modest enclosure and the same set of sockets as its cheaper brother. $2500 is not a small price for a device of this size. Norwegians argue however, that the HD25 can be placed next to the best converters available on the market.
HD25 is one of those devices that you can hardly see on the rack. For me it is a big advantage for purely practical reasons. The relatively small DAC could be placed on the edge of the desk, roughly halfway between the computer and the audio rack. Power came from the conditioner, I also used a normal RCA interconnect and audiophile USB cable, and the front wall of Hegel was still at my fingertips, so I could easily jump between sources. It was useful in the last phase of listening, when I used the CD transport with coaxial output. You should keep in your mind a few things during installation of the HD25 in audio system. The manufacturer gives us a choice of two digital filter modes. This allows for the minor adjustments to the final character of the sound. Secondly, the HD25 accept signals of 24 bit/192 kHz via USB. So we do not need any additional converters to enjoy the hi-res files. However, if you are using Windows you have to install the drivers available on the manufacturer's website. Owners of Apple machines do not need them. Hegel foresaw also facilitation for users who are not interested in the hi-res files. If you belong to this group, you can use a small switch on the rear panel to enable the 96 kHz mode. Then there is no need to install drivers and HD25 works like a typical plug and play device. The DAC is equipped with adjustable analogue outputs, so we get the ability to control the volume. It is a pity that we can not do this by touching the front wall, but probably most people will use a small flat remote anyway. Then the HD25 works as a preamp, and we can think of a good power amplifier instead of an integrated one. The analog signal can be derived from RCA or XLR sockets.
Cons? I did not like that the device is mounted on three small legs. Perhaps it limits the transfer of vibrations to the enclosure, but in such a small device I would prefer four-point support.
I must admit that my expectations for this flagship model were high. I was expecting that membranes in my speakers will explode, and the musicians will materialize in a room during the first listening. However, Hegel began its show with a sense of calmness typical for high-end products, and didn't want to knock the listener on the shoulder within five minutes. My first impressions were confirmed after a week of listening, which is a clear proof that Norwegian source is versatile and predictable, which to me is good. HD25 is not a device that puts some specific aspects of sound superior to others. It's a quintessence of audiophile neutrality and music synthesis. Perhaps for this reason, initially nothing knocked me off my feet. You do not have to get used to sound so natural and balanced. After a few songs we stop thinking about the proportions between the different parts of the band, dynamics, clarity and bass. Recognizing that this sound simply does not have any drawbacks should take no more than ten minutes for people calling themselves audiophiles.
From this moment on you can start discovering music with the HD25. You know that everything will be done with a dose of normality, but Hegel just shows its flair. How? That resolution, dynamics, and the ability to paint music in a very nice, elegant way. For me, the ability to show large number of details, but in such way that we feel relaxed during listening, is one of the biggest advantages of this DAC. HD25 does not change the music and it does not apply any strange tricks. This device only tries to achieve the highest quality of the sound with the high fidelity to the original recording, whatever this recording was.
The reflection of this philosophy can be found in every single element of sound performance. If you start looking at the bass, you will see that in fact it is quite normal, but it can go lower and react a bit faster than you got used to. The same thing happens with the sound stage. It has the correct shape and at first glance looks pretty ordinary, but upon further analysis, we conclude that it is very precise and stable. Midrange is neither warm nor cold. HD25 skillfully combines resolution with natural sound temperature. The list goes on, and on, and on.
Build quality and technical parameters
Hegel HD25 is a digital to analog converter with two coaxial digital inputs, one optical and one USB Type B, and analog outputs in two standards - balanced and unbalanced. We have three-pin power plug with mains switch and fuse. On the front panel there is only a blue display. If you want to change the source, you need to double tap the front panel. The interior was clearly divided into a two sections - power supply located on the front and the main section - two circuit boards at the rear of the housing. USB input is isolated from the rest - ground and power were routed separately to this circuit board. In their flagship DAC Hegel applied many AKM parts - AK4115 is the digital receiver of coaxial sockets, further we see the AK4127 frequency converter, and AK4399EQ is responsible for fundamental C/A conversion. The use of innovative silicon-germanium transistors is quite interesting. In the power supply we see two capacitors 10,000 µF each, and a toroidal transformer bolted to the base of the enclosure through a foam ring. Critical parts of the chassis are lined foam to prevent vibrations. HD25 is quite hot during work, but there is no need to put it in a completely open space. Several notches in the housing and a row of holes in the top section of the rear panel provides propper ventilation. A clever and practical solution.
Audium Comp 5, Sevenrods ROD4, Naim CD5 XS, Naim NAC 152 XS, Naim NAP 155 XS, Albedo Geo, Cyrus CD t, Tellurium Q Graphite Digital RCA, Audioquest Cinnamon, Enerr AC Point One, Enerr Symbol Hybrid, Enerr Holograph, Audioquest NRG-2, Ostoja T1.
Listening to the HD25 reminded me of driving a car, which had just been fixed - a few things in the engine, replaced filters, shock absorbers and brake pads, and finally better tires. We drive off and feel completely comfortable - the seat, steering wheel and mirrors are set just right, and we know how to operate every knob. At first we don't feel anything special, but with each mile we notice that acceleration is much better, nothing knocks on potholes, the steering is perfect, strong brakes and new tires give us the confidence to really enjoy the ride. It is just better. Norwegian DAC showed me the music I know, but made the listening much more pleasant. I did not want to stop, so the review lasted a little longer than usual.
DAC type: 32-bit
Output voltage: 2,5 V
Digital inputs: 2 x coaxial, optical, USB
Analog outputs: RCA, XLR
Frequency response: 0 Hz - 50 kHz
S/N ratio: 145 dB
Dimensions (H/W/D): 6/21/26 cm
Weight: 3,5 kg
Manufacturer: Hegel Music Systems