Burson HA160DS DAC/Amplifier

This is my review of Burson HA-160DS, which I have been lent for a few weeks by an Italian dealer.
This DAC/amplifier combo has been tested in relation to the following gear:

Headphones:
Audeze LCD2
AKG K501
Yuin PK1
Apuresound Etymotic ER4P/S
Etymotic HF5 (with and without PtoS adapter)

Amps:
CKKIII

DACs:
Audio-GD NFB-9.2

I wanted to compare its amplification stage (the main dish of Burson HA160 line) to my DIY Cavalli CKKIII amplifier. I compared the HA160DS dac portion to other sources, like Audio-gd NFB-9.2, and a few portable sources. I have strong experience with several DAC’s, although at the time of this review (Easter 2012), I had the Audio-gd DAC as main mean of comparison.
 
Tonality and general character

The general impression of the Burson amplifeir is that it’s smooth sounding, very powerful, slightly bassy, and that it gives its best with higher impedance headphones, especially compared to similar performing designs. It has plenty of power and doesn’t suffer when powering the highest impedance loads I have used (AKG K501) at full volume. While I didn’t reach an eardrum-breaking volume level, I couldn’t hear any distortion when the volume pot was turned to max.
I think that big part of the amps smooth caracter is given by the discrete opamp design: basically, instead of integrated opamps (as usually found in audio, but hardly made with that aim in midn), Burson designed their “opamps” using discrete components.
The amplifier runs pretty hot, much hotter than the CKKIII (which stays cool, basically): I think it’s both due to the power delivery (higher, with the Burson), but especially because of the discrete opamps, which seem to run hotter than regular integrated opamps.
 
Impedance tests / Headphone listening:

In short, I believe the Burson offers its best when used with middle to high impedance cans, while an amp like CKKIII does its best with low to middle impedance cans, bettering the Burson only with low impedance, easy to drive headphones.
The CKKIII is also a slightly edgier amplifier, although free from real treble peaks. In turn, the two keywords which could decribe the Burson amplifier section would be: smooth, (mid) bassy.

First, a critical test: I tried the Burson with very low impedance IEMs, Ety HF-5: these are 16 Ohm Etymotics, and with them, the Burson strives in rendering microdynamics and microdetails. With the same IEMs, the CKKIII is more capable at handling both the bass and the microdetails.
I had used the CKKIII in the past with JH-13 also, with decent satisfaction; while I wouldn’t stick to a custom IEM for home listening, I still feel that, with lowered gain, the CKKIII would be a good choice even for very sensitive IEMs.
I wouldn’t advice to use the Burson with sensitive / low impedance IEMs in the first place, unless those IEMs could benefit from an impedance adapter (some do, like Etys; others don’t, like Westones).

Things changed already when pairing the HF-5 with a PtoS 75 Ohm adapter: such adapter makes the HF-5 basically an ER4S. In such situation, the Burson and the CKKIII drive the Etys similarly; these “modded HF5” become a bit brighter due to use of the adapter, although not as much as Apuresound ER4S (ER4P converted through the same adapter). The CKKIII gives a tighter presentation of the sound, the Burson has a bit more bass slam, but also less definition in the low frequencies.

Using Apuresound ER4P (it’s ‘just’ 27 Ohm, but weirdly it’s much less sensitive than stock ER4P, with identical nominal impedance), there is again more bass slam with the Burson; otherwise, both amplifiers drive them very well, and the HA-160DS doesn’t show any of the problems it has when driving the HF5 without an impedence adapter.
Apuresound ER4S gain too much treble, and their shrill timbre is apparent with both amplifiers (perhaps also due to some contribution from the NFB9.2, which occasionally presents some upper treble energy excess).

At the other extreme of the impedance chain, there were AKG K501: the Burson seems born to drive AKG’s. It made these cans sing, with their wonderful midrange, tight bass, and with a sense of “freedom” caused by the lack of sense of effort. The K501 aren’t known to have a huge soundstage on their own, but they did sound very open. Given the character of the K501, they still had some sibilance in the 8 kHz region, which was very hearable when singers pronounced the “s”; still, what I really loved of the pairing, was the sense of power, of effortlessness, and the capability of the combo to make vocalists “sing” in a human, believable way.
By comparison, I have always found the CKKIII to strive with similar AKG or high impedance Sennheisers (in the latter case, losing treble control with HD250 linear 1 and 2).

Testing the Burson against the LCD2 showed a different behaviour: the Burson makes the LCD2 warmer, darker; the CKKIII, in my opinion, makes the LCD2rev1 more U shaped, bringing out the highs much more; with the CKKIII, the LCD2rev1 gets more detailed, and reveals an upper treble peak, after 10 kHz, which translates to a much livelier soundstage, bigger perception of microdetails, but also somehow glaring, more clinical sound reproduction. The buyer of my CKKIII, who also owns a Burson HA160, loves the CKKIII with his LCD-2.
Personally, my grief with LCD-2 is that their balance doesn’t convey the midrange I want, hence I couldn’t assert a preference.

Yuin OK1 sounded smoother with the Burson; being able to go a bit up with the volume, given this sense of smoothness, the perceived dynamics in listening are also a bit better.

I did notice, with Etymotic HF-3 (without adapter), that they could pick up the mains noise through the Burson, sensibly more than with the CKKIII. This mains noise was volume-pot independent. In turn, the CKKIII was adding white noise (which the Burson doesn’t), which was also volume pot dependant.
 
The Burson DAC

I think the burson amplifier doesn’t act like a bottleneck against the sources I have used in this test. I have been listening to the aforementioned headphones using both the Burson internal dac, and Audio-gd NFB-9.2. While evaluating the internal dac against the Audio-gd NFB-9.2 (which, for the sake of saying, is almost one order of magnitude more expensive than the ‘premium’ paid for the Burson’s dac), I reached the following conclusions: if I bought the HA-160DS for its amplification capabilities and transparency, I wouldn’t want to stick to the internal dac, since I’d be limiting what the amp is capable of letting through; the internal dac sounds a bit on the sterile side. It’s not sibilant, not “irregular”, but it’s not very organic either, and doesn’t provide very high detail retrieval nor big imaging.
On the good, it has a certain sense of delicacy to the notes: its main limitation is the lack of vividness, and the general sense of digital feeling. While it’s better than a portable source (more delicate, but lacks some body to be found in certain DAPs, also), I don’t think it’s on the same level as the amplifier.
The DAC can be used easily with a computer, the peripheral is completely plug and play. USB recognition is immediate, without the necessity to install any external drivers.
While I could well understand that, given a budget, the dac could be considered a “nice addition” over the amplifier alone, offering a compact, stand-alone able to pick the signal from USB (or spdif), if I considered to upgrade to a better source in a nearby future, I’d feel that the premium paid for the dac portion would lay unused.
Depending on the middle-long term intentions of a buyer, this is something that needs to be considered.
 
Conclusions:

Burson offers a DAC/amp combo which sees its strength mainly in its amplifier portion. It offers plenty of power but it has a bit too much floor noise and is a little too smoothered.
The tonality is warmish. The lower frequency of the spectrum is just a bit cloudy, could enjoy more resolution, but this amplifier can be a bless in situations like when driving AKG K501 or other headphone which are difficult to “squeeze” and made lively or to ‘slam’ (which anyway, would seldom happen with K501).
Given its power capabilities, I consider Burson’s amplifier a pretty good purchase for people using dynamic cans, especially mid to high impedance cans, damped orthos, and such. I wouldn’t swear by it for Grado’s, unfortunately. Given my appreciation for RS-1i, if I had to buy them, I might actually try a tube amp with them, or a solid state amplifier which has better impedance matching for low impedance headphones. As far as Sennheisers go, while I haven’t tried any HD600/650/800 with the Burson, in those cases I’d likely rather go for a balanced amplifier (HD6xx), or something just much better (for the HD800, being it a DHT amplifier or a solid state amp that sounds better).
While there are diy offerings, like CKKIII or M^3, reaching similar quality level for a sensibly cheaper price tag, the Burson manages to be fairly thanks to its build quality and power reserve, much better than most (if not all) chinese products and diy products. It’s built like a tank, and there aren’t any sharp angles anywhere. The volume pot is very unsensitive to white noise when raising the volume, even though its rejection to wall noise should have been treated much better.
In general, I would hope for an improved “dac/amp” combo offering a better DAC. As it stands, if I planned to go for a better sounding source, and wanted a Burson’s amplifier, the amp-only version would be a better investment in the long run. Other people’s mileage may vary.