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Positive Feedback ISSUE 22
november/december 2005


HeadRoom's New Micro-Stack: This Year's Xmas Goodies?
by Max Dudious


As the Winter Solstice rolls inexorably toward us, our audiophile thoughts turn to what we might extort, wheedle, blackmail, or just beg from our friends and loved ones. Admit it. We're all a bunch of gear-whores who'd do a lot of sweet-talking to listen to the latest and greatest in our homes. That's why reviewing is so much fun. But you guys, with your deep pockets (you know who you are), get to keep these toys. So it is with great glee that I'll do a quickie review of HeadRoom's recent Micro DAC and Micro Headphone Amp, and provide you (free of charge) with a strategy to justify your gear-lust, and to help your Xmas along. These li'l darlin's are true high end performers, not so expensive that no one but neurosurgeons can afford them, but dear enough at about $300/per to register on the Richter scale as a more "serious gift" than another pair of gloves.

For my auditions I have had on hand an Optimus CD 3400, an audiophile favorite of about ten years past, that is distinguished from other portable CD players by having a terrific CD transport for its price, and a digital output (that is to say, one can bypass its onboard DAC as well as its onboard audio amplifier). This means I can isolate the sound of the DAC, or the micro amp, then disconnect them and listen to the Optimus's DAC and amp, or compare it to the sounds of my Sony CD Walkman D-E356. Or I could use either the inboard line amp or outboard headphone amp, listening to the Optimus through my Grado SA-1 Headphone Amp. I listened to the various combinations of gear through the Sennheiser HD 650, the Grado RS 1, and the Shure E5c headphones. The results, given my ancient ears, were not unpredictable. For various music, I liked all of them. But as T.S. Eliot once allegedly said to a student: "Yes, Virginia, we understand that you love Shakespeare. Now you must tell us how you love him."

In a recent article in The Absolute Sound Dan Schwartz surveyed a handful or headphones, among them the three I have around the house most of the time. (See The Absolute Sound; October, 2005; "The Headphone Diaries – Coffee Table High-End.") There Schwartz makes the following observations: He doesn't like the Shure E5c's, which I love. Mostly he complains of not being able to seat them in his ears properly. Yes, we each have different sized and shaped ears. Shure offers three different sized foam isolators to overcome this, as well as a triple-flanged soft-rubber industrial type. That would mean that without a good seal, he hasn't heard the Shures reproduce deep bass, one of their strengths. The moral, my friend, is written on the wind—try before you buy. He praises the clarity of the Grado headset, saying; "Grados sound different from everything else, with a unique hear-through-the-veils kind of transparency." I still find Grado ‘phones pleasing, and they remain among my favorites, while other (usually younger) audiophiles sometimes find them brash. Over all, Schwartz liked the Sennheiser HD 650 model second only to the AKG K 501 on mid-range. But of the AKG K 501s he found, "... there is no serious bottom end forget the organ pedal in the Zarathustra intro." He thought the 650s excelled at orchestral music, not quite as forward in the upper reaches as the Sennheiser 600s, which they replaced. He never says as much, but he seems to like the Sennheiser's overall balance and the Grado's transparency best.

We are in collegial agreement there. Where we differ is with the Shures, which, when seated properly in my ear, have some of the best traits of the Sennheisers and Grados. The Shures, to me, have the transparency of the Grados without the brightness, and the balance and control of the Sennheisers with but the slightest veiling, and with better controlled deep bass.

Much of who likes which headphones best is a function of many variables (sex, age, hearing, what their big rig sounds like). I'd say the differences between most first rank headphones are small when compared with the differences between loudspeakers. The frequencies are all there, but the differences are in the presentation. One set of headphones has more detail and puts you up front in the acoustic space, while another has detail but manages to put you back further in the acoustic space. Some folks like one, while some like the other. Not one has the irritating sibilance (tizz) or false bass (boom), that most inexpensive headphones exhibit. All these headphones have good dynamics, the ability to go from soft to loud. Some do it in a more startling fashion (good surprise in Haydn's Surprise Symphony), that I value. Still other listeners prefer their surprises with a gentle nudge rather than with an in-your-face SHOUT. So all these comparisons are relative, like looking at data presented on logarithmic graph paper where the last few percentage points are expanded to exaggerate the differences. I could live with either of the top three: Shure for long trips and mixed concert programs, Sennheisers for sit-down sessions with classical music, Grados for listening at the beach to rock, jazz, and classics without the added need for a headphone amp.

Having said that, I think we all might agree that there are pieces of gear, cables even, that we characterize as having "tubey sound," and others that have "solid-state sound." What do we mean when we say "tubey sound?" I'll make an intrepid try to tease out these distinctions. There seem to be two generations of use of that terminology. The first is the sonic thumb-print old classic tube pieces projected. I'd say they were rolled off on the extreme high and low octaves (not enough storage capacitance), had overly much warmth in the mid-bass/low mid-range (oil-filled paper caps), attack and decay were not well controlled (not stiff enough voltage regulation), which translated into overmuch "bloom." While their dynamics didn't suck, they improved notably if quadruple the amount of original filter capacitance was added. At their worst, tube gear was warm and wooly down in the frequency range, tizzy in the presence range, and rolled off in the upper octave or two of the audible frequency range. Their midrange bloom was euphonically beautiful. Modern tube equipment manufactured in the past ten or fifteen years corrected a lot of these problems and aimed for more "bloom" that approximated the sound of the classic old gear.

Compared to classic tube gear, recent transistor sound seems to have less "bloom" (probably a type of ringing), better attack and decay (stiffer power supply regulation), greater extension of the frequency range to include the top and bottom octaves, less measurable distortion (better parts, voltage regulators, transistors having inherently less distortion than tubes), and better control of woofers. The trade-off with older transistorized amps included less warmth, less bloom, an overall leaner presentation, with an etched mid-range that could create listener fatigue. I think, with the exception of Single Ended Triodes, modern tubed amplifier designers have worked to exorcize the flaws that seemed the inevitable tube sound, but which was really the sound of passive parts (resistors, capacitors, chokes, wire) more than the sound of the tubes. Over the years first-rate tubed sound has more and more come to resemble first-rate transistorized sound, with only some hints of overmuch warmth and bloom. A small number of design engineers actually have worked to get their solid-state amplifiers to sound more like tubed amps (loading up the signal with even-order distortions), though the natural flow has been getting tubes to sound more like transistors. Transistors, at their best, sound crisp and clean, well balanced and mellow. At their worst they sound harsh and grainy, overly etched and irritating like music through a pair of cheap (throw away) headphones.

For my software in this listening session I used only David Chesky's Area 31 (Chesky hybrid SACD 288), with the Area 31 chamber orchestra conducted by Anthony Aibel. It is a variously orchestrated album that might have a full, if chamber, ensemble in some movements, while paring down to a smaller ensemble for other movements. Each movement features a soloist, either a violinist, flautist, or soprano, and the slow sections are particularly revealing. For example, in the 2nd movement of the violin concerto, I think I hear the jazz standard "Spring Is Here" in the opening, only slower than usual and in some minor mode. The more I listen to this work the richer the experience becomes. Area 31 has also been noted as an outstandingly well-engineered CD in all the reviews I've read. And using only one excellent album reduced the number of variables and times I'd have to switch things around. All the usual sonic stuff you might want to listen for—dynamics, timbre, spaciousness, cleanliness, balance of frequency range, lack of tizz and boom, and the rest—are here on this recording. But they are turned into virtues. That is to say, there is a lot of spaciousness, the sound is very clean, there is nearly no tizz nor boom, etc. etc. as you would know if you heard it on a good quality big rig.

Some of my observations are these: the HeadRoom Micro Amp sounds like a top-quality solid state line stage with the sound quality of an excellent up-to-date design. I find it cleaner than the big, balanced, for a while top-of-the-line HeadRoom BlockHead that I found wanting at its $3.2 K price in a previous review (see PFO Issue 20 at I think it is quite an engineering feat to come up with a Micro Headphone Amp that is quieter (battery powered supply), cleaner & crisper (with fewer soldering joints over-all, and fewer miniature capacitors), yet equally spacious with its cross-feed circuit—all at 10% of the retail price of their big, dual mono, balanced line, BlockHead. This piece lends credence to the saying, "Less is More." Compared A/B to the Grado SA-1 headphone amp, the Grado is a notch or so more tubey than the Micro-Amp, with a tad of the Doris Day filter. I feel the Grado is a bit prettier in its presentation of, say, a solo cello, but now the Micro-Amp sounds a bit more analytical, more detailed, and more like recording-studio accurate to me.

Similarly, the stand alone Micro-DAC. Compared to the on-board DAC of the Optimus CD player, the Micro-DAC sounds bigger, with a somewhat larger soundstage, and is a noticeable notch cleaner, which allows the listener to play it as loud as necessary. A while back I heard it said a stand-alone DAC has a lesser chance of getting the slave clocks in synch with the master clock, resulting in more jitter. That problem seems to have been solved by the guys who do the mods. Nowadays, the clocks have been optimized (as you can read in the various after-market catalogues of modifications now available). You may have noticed that there are fewer DACs being developed each year, and fewer articles about jitter. That sort of fits my notion that this year's mods will be incorporated into next year's chip sets. But, there are improvements to be had with this stand-alone DAC, and if you are a perfectionist, then you ought to have one. It has much the same sonic thumb-print as the Micro Amp, as might be expected from a "sister piece" with an identical power supply and similar analog circuits.

As compared with the Optimus (no longer offered) on its own, whose strength was that its transport was originally built for computers, the question is this: how can anyone expect a Walkman type CD player that's built to a price ($179), with a notch or two above average transport, also have a really good DAC and line amp? It can't! and still make its price point. But with any CD player that offers digital output, you can get not just good, but nearly the best sound I've heard from a headphone rig. The HeadRoom Micro Headphone Amp plus their Micro-DAC offer up sound on a par with the highly rated Lehmann Black Cube (doubly improved) phono section. The Black Cube sounds big and clean with lotsa zotz. For their similar virtues I recommend the HeadRoom pieces highly, together or separately. There is a lot of value for money, and lotsa zotz, or bang for the buck in these Micro-pieces.

Some incidental but important items: interconnect cables are important!! HeadRoom recommends using a half-meter Straight Wire pair of interconnects, which they supply. That wire sounds a tad on the soft side, to me, with the highs sounding a bit rolled off. Maybe that's HeadRoom's notion of a good symbiotic wire to pair between the Micro DAC and Micro Amp, which are together just an iota of a tad sharp. It's like the mixing of tubes and transistors, a stratagem has worked in many applications, and it costs less than $30. If you like the combination as I've described it, be sure to insist on stereo Sony Mini plugs on both ends when you phone or email your order. On the other hand, there is a mono-looking (but stereo) grey 0.5 m. wire at Radio Shack, sold in blister pack with Sony stereo mini-plugs, that will add some more clean, sharp details to the upper octaves for less than $15. I leave it to you to pick and choose this important part of the complete set up. I'm certain my ears are different than yours, so I won't make any recommendation. Of course, you could always get both, to illustrate to your less sophisticated friends just how important passive devices can be to the character of the sound.

The Taiwanese wall-wart transformers (15 v. at 240 mA) that come with these HeadRoom pieces are pretty good. I think they are a tad behind the two nine volt batteries in terms of quietness for serious listening, but they are from a good manufacturer (Advanced Power Solutions). I use a look alike transformer power supply (13.5 v. at 1700 mA) with my Sonic Impact amp in my indoor rig at my beach shack on the shores of the Chesapeake, dude. So while I prefer the battery supply (even with having to keep a stash of 9v. batts on hand), I don't think you'd be losing very much sonic purity using the wall-wart, and you may be gaining some zotz.

(Did I tell you I recently saw one of the latest surfer movies in my insomniac haze. One dude was being interviewed, after conquering some 100 foot waves 100 miles off San Diego, and he was asked, "How do you know the real surfer from the poseur?" And his answer was, "The real surfer never uses the word Dude." I was crushed, dudes, crushed.)

Let's review. The HeadRoom Micro-Amp and Micro-DAC are small and relatively lightweight enough to be used while traveling. They score high on my portability scale each being about as large as a four medium length cigar case. They each can be operated with a wall-wart power supply (supplied), or with two (9 volt) batteries. They are sensitive to the quality of interconnect cables and reflect the sound of the cables (tubey-warm vs. transistor-bright). You can "voice" the system by choosing a pair of interconnects that suits your taste, or headphones. Together with a good front end (CD player, amp) you could set yourself up with a really nice pair of headphones and come away with a truly first class headphone system for about One Kay, that's a thousand dollars, to those in the know. And just what is it that Those In The Know, know?

That may sound like a lot of money, but it isn't when you compare it with a floor standing big rig for your living room. I think true audiophile sound, as good sounding as these HeadRoom twins, has to cost a great deal these days. Most audiophiles don't take a phono cartridge seriously if it costs less than Two or Three Kays. The system as described (but without the DAC) can be had for as little as $750. So the Micro-Stack checks out for portability, flexibility, value for money, and great sound.

Oh yeah, I forgot something: privacy. You know how couples are always pecking away about whose taste in music is really totally happening? I guess you know the drill. "Honey, how come every time I want to listen to Aretha Franklin, you want to listen to Renée Fleming?" A high class headphone system eliminates those squabbles. Finally, I'd like to add, everything I've said about using a CD player as a source should be true of the Micro Amp connected to an iPod as well. There you have it.

The HeadRoom Micro DAC is one for the connoisseur who has a CD player with a digital output. The HeadRoom Micro Amp is one for a guy who wants more punch than his CD player alone can give him. It can be played with the Grado, Shure, or Sennheiser headphones mentioned above with no impedance mismatch, and the sound with either is revelatory, from the most elegant brushes killing me softly with their deft contact on cymbals, to tutti passages blowing me away with vigorous tympani and bass drum, celesta, strings, woodwinds, and soloist, all in full cry and incredible focus. This exemplary Area 31 SACD is held together by David Chesky's music and the Chesky engineers, but brought to your headphones by the HeadRoom engineers, who capture all the music just right with their illuminating Micro DAC and Micro Amp. So either of these two entries from HeadRoom can make a wonderful present you can try to cadge from those near and dear, or they can be a present you buy yourself, or (you sly devil, you) a present you buy your wife so she can listen to her favorite music in privacy and without your arguing about whose music you have to listen to—but which you borrow when you don't want to keep her awake. Heh, heh.

When you order directly from HeadRoom, be sure to tell ‘em, Maxie sent ya. Remember, "revelatory and illuminating."

Ciao, bambini.

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