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Reviewer: Frederic Beudot
Digital Source: Musical Fidelity A5 CD, Accuphase DP55, Atoll CD200 [in for review]
Headphone Amp: Musical Fidelity Xcanv3, Creek OBH11se, Rudistor NX-33 [in for review], HeadRoom Balanced Desktop [in for review]
Cables: Zu Gede (RCA and XLR), Consonance Billie interconnects
Headphone: Beyerdynamic DT911, AKG K701, Sennheiser HD650 [on loan]
Power Cords: Cobalt Ultimate
Powerline conditioning: Monster Power HTS5100mkII
Sundry accessories: Isolpads under electronics and speakers, Standesign stand
Room size: 15' x 30' opening to 3 other rooms. Short wall setup
Review component retail: Headroom Balanced Desktop ($1696 as reviewed)

Headroom's Balanced Desktop is the third (and, at least for now last) installment in my exploration of balanced earphone operation; Part I looked at the technology and Part II reviewed the musically highly involving and organic Rudistor NX-33.

Let me clarify one thing upfront. This review will not be a shoot-out between these two amps. They both have strengths and weaknesses. They have to at this price point. Plus, they don't even target the same audiophiles so a head-to-head comparison of all sonic attributes would be of little value though when there are fundamental differences, I'll point them out to support a more informed choice. If I have a favorite at the end, it does not mean it should be yours. That's what the thousands of words after this introduction are all on about.

HeadRoom has been at the forefront of headphone amplification for years, first initiating the world to the idea that there is a lot more to headphone listening than the anorexic output of integrated amplifiers or receivers would suggest by introducing the audiophile community to dedicated earphone amplifiers, a category of gear whose utility none of us would question today but which was far from a home run when Tyll Hertsens first started on his quest.

Once this battle had been won (something the number of dedicated amplifiers on the market and the range of technologies employed would attest to), Tyll did not stand still. He pioneered another revolutionary concept, balanced amplifiers and headphones, taking musical reproduction another giant step forward in cost-conscious fashion.

For the past five years, Headroom's lineup of balanced amplifiers and modified cans has been progressing and growing. At the very top sits the Max Balanced ($3999 to $5597 depending on options), which is capable of driving 2 pairs of balanced headphones in pure class A balanced operation without a sweat. Second from the top is the Home Balanced ($2296 to $3596) which allows access to most of the Max's modules and qualities in a more affordable package. Finally there is the object of today's review, the brand-new Desktop Balanced ($899 to $1696 depending on options), an exercise in miniaturization and cost containment aimed at offering most of the benefits of balanced operation in a more manageable fashion.

Headroom also offers three earphones converted for balanced operation (beyerdynamic DT880, AKG K701, Sennheiser HD650) for a surcharge of $300 over their single-ended counterparts and will modify any of these models for you should you already own them. At the time of this review, Headroom offers this headphone modification free to any customer purchasing a balanced amplifier and a pair of headphones from them. That's a $300 discount for a package acquisition.

The single-ended Desktop amplifier has been thoroughly reviewed in many publications, including by Ryan Clarin in these pages. Hence I won't spend much time going over all its features and basic sonic characteristics. Instead, I will focus mainly on the key differences between single-ended and balanced operation. Neither will I spend a lot of time on the benefits of and technology behind balanced drive. Those were covered in detail in Part I and II of this triptych.

The first balanced difference you will see versus a single-ended Desktop is obviously on the front face. The customary ¼" and mini outputs have been replaced by two balanced female connectors (one left, one right), but those clever connectors also host a ¼" plug in their centers, allowing the Balanced amp to drive either one pair of balanced phones or two pairs of conventionally single-ended ones. Since I will not return to single-ended operation, let me just say here that it was surprisingly powerful and dynamic. While there was no mistaking the differences with balanced operation, the performance gap did not seem as large as with the Rudistor, a nice benefit for those planning to stay with both technologies.

Also gone from the face is the brightness switch which allowed listeners to dial in an HF boost to offset the impact of the cross-feed circuit. It seems lack of internal space was the cause for this feature's elimination but in all fairness, not once did I miss top-end sparkle. The cross-feed circuit remains and I'll refer you to Ryan's review for the specifics. Besides adding a little weight in the bass, I really did not detect any major changes in soundstaging when engaged. That should not come as a surprise. The AKG K701 is a soundstaging champion by headphone standards and balanced operation all by itself improves this attribute significantly. The contribution from the cross-feed circuit under those conditions was very minimal. When used single-endedly with the HD650 (the other end of the headphone spectrum with a fairly narrow and centered presentation), the cross-feed benefits were more obvious but again not radical though pleasant. After playing with the switch a few times over the first few days, I left it on for the rest of the reviewing period and completely forgot it was even there.

The second switch on the front face sets gain between low, medium and high to adapt to specific earphones. The Desktop I reviewed was equipped with the $199 stepped attenuator upgrade which made use of the gain switch even more critical than it would have been with the standard Alps Pot. With the switch on high, I could barely move past 8 o'clock on the volume control and the steps where just too coarse to find a comfortable level. On medium gain however, I had to turn the volume control all the way to 1:00 or 2:00PM to get the dynamic contrast I knew the amplifier to be capable of. After a bit of tinkering and experimentation, I found settings that suited me. Eventually I found another solution by using high gain, attenuator set to around 10 o'clock, signal routed through the internal DAC and Foobar2000 set to digitally adjust volume levels, actually restoring a continuous if virtual volume control (Foobar's volume adjustments are made in 0.15dB increments).

On the back of the amplifier things have changed as well for the balanced model. It is now equipped with a set of balanced inputs added to the RCAs. The choice between either is made by switch. It allows connection of two separate analog sources and toggles between them although it would have made my life much easier had the source selection switch been located on the amplifier's front (the fully upgraded Desktop sports three such switches in the back, a two-way to toggle between digital and analog input, another to choose between balanced and single-ended analog and a three-pole switch to select from between USB, coaxial and optical digital inputs).

Overall construction and feel are very sturdy, with inputs bolted to the chassis and spaced far enough apart to allow for even oversized connectors, a great achievement considering the crowded real estate and something competitors should emulate. The only thing missing on this back panel is a tape loop but honestly, I don't know where Headroom would have fit it. There just is no available space.

Another visible change is the introduction of the new Astrodyne power supply that offers more current on demand for the Balanced Desktop Amp without having to shell out for the $399 HeadRoom Desktop Power Supply. The Astrodyne is also available separately for $99 to supply the rest of the HeadRoom Desktop and Micro amps, purportedly offering performance gains over the previous linear AC wall-wart included with HeadRoom Micro and Desktop models.

The most important changes between single-ended and balanced Desktop amplifiers took place inside of course to accommodate fully balanced operation. The first and most welcome of those is the phase splitter inserted past the single-ended inputs to convert to fully balanced operation regardless of signal. The second change was obviously to adapt the amplification stages to fully balanced mode. The Balanced Desktop can also be upgraded to balanced Home power module, adding the benefit of pure class A operation to the 4 discrete amplification modules necessary for balanced stereo operation.

If you add it all up, the $1,297 review unit had all the possible musical upgrades (Home module and stepped attenuator) plus the $399 optional Home DAC to come in at $1,696. I can't say how any of those upgrades compare to the stock options and whether they constitute a worthy investment but I can clearly say that the qualities and weaknesses found in the upgraded Balanced Desktop did not seem out of line with the asking price. The amplifier clearly outclasses cheaper amplifiers in my house while not exhibiting all of the qualities one would expect from some of the more ambitious designs available, albeit at a much dearer price as well.

The most obvious characteristic of the Balanced Desktop is its ability to drive earphones in fast-and-furious style. Even though made and designed in the US, it clearly belongs in the PRaT family our British friends so clearly favor. The Desktop's emphasis is on the leading edge of notes, on timing and details small and large, not so much on note decays and all the subtle variations of tone that can inhabit a note. The Desktop does not take much time to linger on, it is always already moving on. Another of its strengths is bass reproduction - deep and tight, lean without being dry, alive with low level details.

These sonic strengths were absolutely fantastic on Renaud Garcia Fons' Arcoluz [Enja, ENJ-9478-2], a firework of complex rhythms with upright 5-string bass, guitar and percussion intertwined. The Desktop reproduced the deepest bass notes and all the low level detail coming from the archer stroking the strings, the metallic and diabolically tricky rhythms of the gypsy guitar and the tight and purposely dry impact of the percussion. Playback of this disk through the Desktop and AKG K701 had me on the edge of my seat from start to finish. Even the Rudistor NX-33 could not quite keep up with the frenzied speed and deepest bass of the Desktop.

The Desktop Balanced really shone on all recordings thriving on speed and bass muscle. All of my U2 disks got a lot of play through the Desktop. So did REM's Best of. All of these discs took on a new life mainly down below that I did not know they were hiding. Even my wife borrowed the amp a few times to listen to the Gorillaz' G Side (but she did like the HD650 better than the AKG since you can't have enough bass for the Gorillaz, can you now).

The flip side of this was that the HeadRoom could sound somewhat hurried with discs requiring more finesse and subtlety. If you have read Part I and II, you already know that classical vocal music is one of the yard sticks by which I measure any gear. Here the Desktop had a few shortcomings.

Before I became fully aware of and understood its somewhat brighter nature and emphasized upper midrange, I paired the HeadRoom with Atoll's CD200 and Zu Gede interconnects. The Atoll is not bright or dry by any means but has a more open and airy midrange than my Musical Fidelity A5 or Accuphase DP55. Coupled to the clarity of the Zu Gede cable, it explained my first impression of excess top energy where the same combination sounded perfectly balanced through the Rudistor NX33 or my McIntosh amplifier. All this is to say that component matching will be critical to get the most of what the HeadRoom Balanced Desktop has to offer. Start with a tonally dense and rich source and cables that offer a little bit of texture and harmonics of their own (think copper cables like Consonance's Billies or even the silver interconnects by Slinkylinks, which have an incredibly rich midrange beyond what one would normally expect from pure silver if one doesn't mind being robbed of ultimate level of bass extension).

Overall the Desktop is fairly accurate and detailed in the lower midrange of bass and baritone but things start sounding not quite as real as one ascends higher into the upper midrange. The first thing I noticed was brightness with violins which somewhat emphasized their metallic nature, leaving some of their wooden harmonics behind. When a Strad sounds all strings, you know something is amiss. But it was never as obvious as with Paul Agnew and William Christie's recording of Campra's Salve Regina [Virgin Classics 7243 5 45720 2 9]. I have been lucky enough to hear Paul Agnew in a couple of recitals over the past few years. Through the Desktop, he was lacking some of the intensity I remember from those concerts. The Rudistor NX-33 just sounded more natural in how it portrayed all the complex harmonics of Paul Agnew's voice and of Anne-Marie Lasla's viole de gambe. The Desktop did not sound bad or off, just not quite as rich and complex as I would have liked, being rather lean, fast and precise, a presentation I am sure will seduce others.

With large orchestral works like Berlioz's Symphonie Fantastique directed by Riccardo Muti [Seraphim Classics 7243 5 73554-2-1], a flamboyant if not extremely lyrical interpretation by the Philadelphia Orchestra, the Balanced Desktop's dynamics were a fantastic asset especially in the fifth movement where a monstrous Sabbath takes place after the hero's death and the Gothic "Dies Irae" theme gets perverted into a caricature of demons and witches (which got Berlioz in a fair amount of trouble with the Catholic church). Through the Desktop, violin pizzicatos were tight and clear, the bells loud and powerful and all three bell calls with their distinctive sounds intact, making it possible to hear deep into the orchestra even if the music did not unfurl fully into its usual 3-dimensional panorama, a headphone rather than Desktop issue. If anything, the ability to listen deeply into the string section partially overcame the usual limitations of headphone listening.

On older recordings however like Richter's 1960 reading of Beethoven's First Piano Concerto with Charles Munch [RCA82876-59421-2], tape hiss was too bright to be ignored and eventually intruded in the listening experience. Through the competing Rudistor NX-33, recordings from the golden era of stereo took a whole new life for me which managed to put forward all their strengths and minimized tape noise by pushing it into the background. The Balanced Desktop just made it more difficult to ignore tape noise, one of the trade-offs that comes with analytical power.

The Desktop's external power supply allows for power cord swapping but I did not give it a try although to my great surprise, the amplifier proved extremely sensitive and responded very well to power conditioning. The Monster power unit I use did a great job of smoothing the top end not by removing detail but by adding fluidity and sweetness wherever it had been a bit short originally. If you invest in the Desktop Balanced, plug it into a power conditioner. I live in the countryside mostly surrounded by dairy farms. The difference was not insignificant so I can only imagine the benefit city dwellers will obtain from a similar piece of AC line equipment.

But it was another, even cheaper piece of equipment that really drove home what the Desktop Balanced is capable of. You owe it to yourself to order the Desktop with its Home DAC module. With Headroom's 30-day return policy, the worst thing to happen is having to send it back and swapping it for a unit without the DAC if you don't like it. Unless your usual source costs far more than both CD players I had on hand (Musical Fidelity A5 CD at $2500, the Atoll CD200 at $2000), I predict little risk of finding this investment wanting.

I have tried the Desktop DAC using my Accuphase DP55 as spinner via the Toslink connection as well as the Musical Fidelity A5 CD player. Both sounded equally detailed from the deepest bass to the upper treble and had slightly more texture than through the analog inputs (tremendously more actually when compared to the 10-year old DAC inside the DP55). Overall the sound was a little more refined and relaxed, like stepping up one level in a manufacturer's line, not a revolution but the elusive sense of added elegance and presence we all end up paying a lot of money for (often far more than this $399 upgrade).

I know a $399 DAC lacks credibility but one reason for its giant performance may be that both the Desktop DAC and the Home upgrade (which I reviewed) are truly balanced designs. It is hard to imagine a simpler and more elegant way of getting a balanced signal directly from the digital feed to the amplification stages of the amp. The difference was easy to hear.

Feeding the optical input of the DAC, I could not detect any harshness or excess brightness provided the amplifier was plugged into the power conditioner, otherwise the upper midrange remained a little stiff. What remained was the inherently lean character of the Desktop, aesthetically related to the Musical Fidelity Xcan but with more dynamics, bass, body, punch, detail and overall refinement.

The DAC also includes a USB input which allowed further experiments even though harvesting all the potential of this connection was not as straightforward as I was hoping for partially because of owning a PC rather than Mac. That will teach me. If you have read here and there that Windows Media Player and all the basic music players developed for Windows XP and prior versions are worth little, I have to confirm that to be absolutely true. Connecting the Desktop and my laptop was a breeze. The laptop recognized the DAC and less than a minute later indicated that new hardware had been installed. That was about the only thing easy about the whole process.

Being an impatient individual, I threw a CD into the drive and listened. The sound lacked dynamics and detail. Dull is the best way to describe it. Think $200 DVD player, not really bad but nothing to write home about. On the other hand, watching Gerard Corbiau's Farinelli and being able to actually hear the computer-generated castrato voice with all its technical flaws was educational if not musically satisfying. The castrato voice in this film was digitally mastered from recordings of the same arias by Derek Lee Ragin as counter tenor and Ewa Mallas-Godlewska as soprano. These transitions, harder to notice in a movie theatre, were more than obvious through earphones.

Then I remembered that most of the theoretical benefits should come from reading data from the hard drive. Sometimes theory works. I used Exact Audio Copy to write WAV files of a number of my favorite CDs to magnetic drive and the improvements were significant - more
detail, more depth but still fairly unexciting. The next step was to install Foobar2000 and again, detail retrieval went up a notch, dynamics increased, the top end gained in overall refinement and the treble lost most of its grain. I could feel I was on the right tracks but was running out of ideas on how to take it to the next level. I surfed the net and harvested bits and pieces of information to prepare for my next move. I have to admit that HeadRoom's complete absence of information on their website, on how to optimize the listening experience through the USB connection, was a little disappointing and certainly not on par with the quality of support otherwise available from their site.

One of Foobar's features is a PPHS resampler which I used to resample the 44.1kHz CD data to 96kHz before feeding it to the DAC. This little trick made the largest difference of all. I heard much deeper and more detailed bass, actually more detail throughout as though a veil had been removed which allowed the midrange and treble to sound their sweetest, better than my A5 CD player and its tubed output stage run directly into the Desktop and on par with the Toslink digital input of the DAC. Only the Rudistor NX-33 was capable of a sweeter and overall more elegant reproduction of the highest register but there the NX-33 is in a class of its own. That the Desktop DAC/Foobar combination, set up properly, could even get close is amazing.

On Paganini's Violin Concerto No1 with Maxim Vengerov [Teldec 9031-73266-2], the HeadRoom amplifier and DAC managed to fully keep up with the tremendous speed of execution the Russian violinist is capable of and render more detail than I had ever heard from this disc while sounding less metallic than fed directly from the A5 CD player. Nevertheless, Vengerov's violin never sounded quite as sweet as it could have and did not display all the richness of tone I heard through the Rudistor NX-33 yet the latter could not deliver the sheer feeling of energy and rush this concerto should make you feel. Pick your poison then. This price level is still a land of compromises.

When listening to Michael Haydn's Requiem [Hyperion CDA67510], I became fully aware of the technical qualities of the recording. I could hear deep into the musical mix and catch details I had not previously heard yet I experienced a more difficult time getting emotionally connected. The choir sounded a little more monochromatic than with the Rudistor, not made up of multiple tessitura but defaulting into a uniform voice of its own. The emotional expressiveness of the soloists did not come across quite as clearly either. It was a technically fine reproduction but did not trick me into feeling there.

After a few days of experimentation, I chose to permanently engage Foobar's equalizer. I did not hear any loss of detail from it and was able to use the 18-level equalizer to tailor a curve that better met my tastes. I designed it by ear and it exhibited a 2 to 3dB trough from 622Hz to 3.5kHz! The original curve I had designed also had a treble roll-off above 7kHz but after I plugged the amplifier into my power conditioner, this correction did not prove necessary. The treble could be left alone for life and sparkle without aggression, just not quite the level of sweetness and elegance the NX-33 delivered.

While surfing left and right on the net, I found many articles indicating that ASIO drivers are the way to get ultimate quality from USB DACs, marrying high speed, low latency and direct communication between DAC and computer and bypassing all of Windows' nefarious programs. From ASIO-compatible sound cards to true ASIO software/hardware solutions, there are a few options to get the ultimate sound quality from a computer. Not being that dedicated, I tried the ASIO4all route. ASIO4all is freeware which emulates ASIO through some Windows components. It is not a true ASIO driver but usually considered a good substitute.

Unfortunately I found the program temperamental and had to uninstall/reinstall it multiple times to achieve a fully functional setup. It's not that the program had any issue recognizing the DAC to allow me to set it up. Nor had the DAC any issue with Foobar either even though that setup procedure was not entirely straightforward. The issue had more to do with my inexperience. As I was trying various solutions to see what would sound best, I apparently picked configurations that ASIO4all did not like (like engaging the 96kHz resampler and a number of cross-feed softwares I wanted to compare to HeadRoom's hardware solution and never got a chance to make work). Once I picked one of those incompatible settings, there was no way to come back. ASIO4all refused any and all sound through the DAC and even rebooting the computer did nothing. I had to uninstall and overwrite the software and go through the whole setup procedure again (which I did over five times).

In the end, I listened to Foobar and ASIO4all with no upsampling and no equalization. This seemed to create the fewest glitches. If there was any advantage to this over the non-ASIO setup with upsampling and equalization, I could not hear it. Actually, I preferred the non-ASIO sound in most cases because the benefits of 96kHz upsampling and equalization far outweighed all supposed benefits from ASIO4all.

The last blow against ASIO4all which triggered its permanent removal from my computer was its inability to play any non 44.1kHz signal. This bugged me after I had downloaded hi-resolution 96kHz FLAC transfers of master tapes from High Definition Tape Transfers. When I crashed the ASIO driver once more, I remembered a few choice French curses, un-installed the program and considered myself cured. Those master files have so much detail, life and ambiance that I really did not feel it worthwhile to downsample to 44.1kHz and lose most of the benefits of high resolution.

If you run a computer-based system, you probably should take the time to download this company's four hi-resolution tape transfer samples and give them a listen. I particularly loved the presence of the organ in Saint-Saens' 3rd Symphony. I never before had heard the air rushing out of the pipes in this fashion.

All along this review, I felt conflicted about the Desktop Balanced. I couldn't help but admire its sense of timing and rhythm, its deep, powerful and detailed bass, the incredible flexibility and range of options, which the Home DAC brings to the table. Conversely, I never managed to completely engage and dive into the music as I can with my reference gear. I I have tried to pinpoint the root cause for that and I am not sure I succeeded. The Desktop, unlike the NX-33, is a great reviewer's tool, passing even the slightest nuances between cables for example. The Desktop would be the better of the two amps at recording monitoring. Its slightly forward upper midrange would draw immediate attention to any issue. Ultimately however, I missed the organic and fluid Rudistor, its ultimate level of refinement, its ability to make me forget my reviewer's hat and focus on the music instead.

On the other hand, if you expect your headphone system to be a magnifying glass that lets you hear into a recording in ways that are far more detailed than any speaker system will ever provide; and if you are willing to leave tonal accuracy, harmonics and flow a little behind to do so - then the Balanced Desktop should be right on top of your shopping list. If your headphones of choice are HD650s, then the Balanced Desktop is your winning ticket to take those cans to a completely different level of performance. It will give them the life and energy they otherwise can be short of.

The Balanced Desktop and Rudistor Nx-33 give two fundamentally different readings of the same music. My personal preference goes to the organic sounding Nx-33 but it is nothing more than that, a preference. I don't believe one is necessarily better than the other but I do know that they will not please the same audiophiles. Ultimately, it is better that way. It would be very boring indeed if we all liked the same things.
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