HeadRoom Desktop D/A headphone amplifier
Tyll Hertsens started HeadRoom in 1992, marketing headphone amplifiers that included a proprietary Crossfeed circuit to a really tough market: audiophiles, a population that almost completely rejected headphone listening as not being "serious." HeadRoom's products helped change that. Even more, they made it obvious that dynamic headphones were undergoing a renaissance—if you could drive 'em properly.
HeadRoom wasn't the first company to market audiophile headphone amps—or even crossfeed correction—but Hertsens banged on the drum harder than just about anyone else. Yet HeadRoom never received much credit for that, possibly because Hertsens was so clearly one of us—an audiophile and a bit of a kook, if I'm not being redundant. Other companies managed to seem exotic and high-end; Hertsens was simply one of the guys.
I think of this as the Girl Next Door Syndrome. You know, you still think of little Gail as the kid you used to play cowboys and Native Americans with—until you see her in a gown at the prom and realize you've been living next to a hottie.
I say that mostly because that's exactly what I did. Twice. Although I've enthusiastically reviewed HeadRoom components in the past and regularly listen to headphones as part of my listening regime, I didn't immediately install the new Desktop when I received it, which contrasted drastically with my behavior when I was loaned a Grace m902 ($1695) headphone amp for a week. Then, having had a blast with the Grace, I embraced the Desktop, but wondered if I shouldn't review the basic Desktop configuration rather than the pimped-out (fully loaded) version Hertsens had sent me.
This despite the fact that the fully pimped-out HeadRoom was in the same price ballpark as the Grace, a John Marks favorite (see his "Fifth Element" column in the June 2005 issue) and Stereophile 2005 Product of the Year candidate. That's when it hit me that the fully loaded Desktop was seriously hot.
Good morning little school girl
You may be wondering what I mean with talk of a "pimped-out," or fully loaded, Desktop. HeadRoom offers the Desktop headphone amplifier à la carte. You can buy a basic model without a DAC—but including HeadRoom's stock electronics module, a Alps volume potentiometer, and wall-wart outboard power supply—for $599. Stereophile has one of those, and I'll be following up this report with listening notes on the "plain" Desktop in a month or so. HeadRoom offers multiple options, however, and you can read about these at HeadRoom's website. The unit I reviewed had all the trimmings.
The first option to consider is the electronics module itself, which comes in three flavors: Desktop (standard), Home ($199), and Max ($499). The Home module doubles up on the buffers and ups the circuit bias to class-A; the Max module employs the veddy, veddy sophisticated Burr-Brown OPA627 op-amps. Our sample included the Max module.
Both the Home and Max modules slurp down current like crazy, so if you opt for them, you'll be adding a Desktop Power Supply ($399), a 15V dual-mono outboard regulated supply that fits in the same chassis as the Desktop amp and weighs quite a bit more. Because our sample was built around the Max module, we needed one of these as well.
There are three DAC options as well, also called the Desktop ($249), Home ($299), and Max ($399). The Max DAC, with which our sample was equipped, is built around an Analog Devices AD1896 192kHz Stereo Asynchronous Sample Rate Converter, a "screaming gizmo," as Hertsens says, "that upconverts digital signals into an ultra-high-speed, high-resolution digital signal without relying on the incoming clock, and then downconverts it into the slower 192kHz word stream while interpolating (to get rid of the 'digital' haze) and reclocking (to get rid of jitter) before sending the data off to the DACs."
The Desktop I reviewed also incorporated the Alps RK50 stepped attenuator option ($199). The Desktop is contained within an extruded aluminum tube—essentially a rectangle with rounded corners and an elastic "bumper" holding the faceplate and rear panel to the body. Here's the cool part: That bumper also serves as feet and stacking rail, raising the chassis off of whatever it sits on and slotting together disparate HeadRoom components, even when they're of different sizes. (For example, though not recommended by HeadRoom, you can stack a HeadRoom Micro amplifier on top of the four-times-larger Desktop Power Supply using the bumper's slot and tab connectors.)
If you've been playing along at home, you've calculated that by adding all the options and the outboard power supply, our $599 Desktop, fully pimped out, ended up costing $2095.
Yet you might still be unsure what the Desktop is, exactly. Hertsens completely gets that. "I asked myself what I needed and I came up with a device that I don't think anybody is ready to build yet. I like listening to my portable player, because I like being able to carry my music around with me, so what I really wanted was a Bluetooth kind of gizmo that would allow me to carry my portable around in my pocket and instantly connect to my car stereo and when I came home to seamlessly connect to my big rig or my office rig or whatever.
"We don't have that yet, but that would need to be a bunch of different things: interface, preamplifier, DAC....So I realized that what I really needed was something that could be the center of my personal audio system. I listen to a lot of music at my desk, and my desk was getting pretty cluttered with—among other things—switches, so I thought, why not build all of that stuff in?"
The packed faceplate and rear panel attest to that thought. Let's start with the connections on the back. There are two sets of RCA inputs, one pair of RCA outputs, TosLink, mini USB, and S/PDIF coaxial digital inputs. There's a power-supply connection. There are three mini-switches: one to select between the two analog inputs, one for the three digital inputs, and the third switches between the analog and digital inputs.
The front panel has a power switch, ¼" and 1/8" headphone jacks, rear output On/Off, Brightness contour, Crossfeed On/Off, Gain (Low/Medium/High), and the volume pot.
So what is the Desktop? As configured for review, it was a headphone amp, preamplifier, and DAC. And, oh yeah, because it's from HeadRoom, it was also an ambience-recovery system for headphone listening.
Can I come home wit' you?
My first big question was where to set up the Desktop: in the big rig, at my chairside headphone station for late-night listening, or [gasp] on my desktop? I initially opted for my desktop—on top of my Apple PowerMac G5 computer, actually—which is where I spend far too much of my time.
I almost immediately reconsidered. Not because the mini USB connection was uninvolving (as was the case with the Grace m902)—on the contrary, it was hard to get any work done. The pimped-out Desktop was warm, rich, compelling, and sounded huuuuge. How could all that sound fit inside my head?
As someone who considers himself a music lover first and only incidentally an audiophile (don't we all?), I'd like to report that the reason I immediately began missing deadlines was that I was so entranced by the music that I just had to listen to hours and hours of forgotten favorites.
Well, I did—sort of. But I also began ransacking my house for all of my different headphones: the Sennheiser HD-580, HD-600, and HD-650; the Etymotic ER4S and ER-6; the Grado RS-1; and the AKG 501. Oooooweee baby! True geek fun.
Of course, there was a purpose to that madness, which was to see how well the Desktop's Gain switch worked. The Alps pot had so wide a range, I'm fairly sure I could have driven any of the headphones I had on hand with the Medium gain option, but the Gain switch allowed me to optimize the control range to each set of cans.
A note here on the Brightness filters, which compensate for the warmth of the HeadRoom Crossfeed circuit. I didn't feel the need for them, but they're there if you do. Filter 1 adds a slight rise at about 3kHz; Filter 2 kicks in about an octave earlier.
While I had the Desktop connected to my computer, I decided to use it as a preamp for a simple system consisting of Blue Circle Music Pumps monoblock amplifiers and Dynaudio Micron loudspeakers. The system sounded focused and surprisingly punchy until it occurred to me to engage the Crossfeed circuit—I reasoned that in a small space with the speakers so close together, it was sort of like wearing headphones.
Wrong, wrong, wrong! The result was mushy and unattractive—quite the opposite of using Crossfeed while wearing headphones, when it adds a subtle warmth and ever so slightly reduces that middle-of-the-skull headphone perspective. I mentioned this to Hertsens, who snorted a with-all-due-respect "Duh." So, ah, probably not as good an idea as I thought.
Although I enjoyed using the Desktop as a preamp on my desktop and in my big rig, I used it a lot more as a refuge. It drove my headphones, it enabled me to get better digital sound from my computer, and it let me switch among several digital and analog sources. Do I need a $2095 device to do that? Perhaps not. I have a lot of things that are probably better than I need—or deserve. Add the pimped-out Desktop to a long list that includes my Telecaster, Trek road bike, and computers. I could get by with less, but danged if it don't feel good to have the ones I have.
If you let me, I can tease you baby
Rich, warm, punchy, powerful, detailed—I'm pretty much using up all my store of adjectives on the pimped-out Desktop. It allowed me to hear the interplay of the overtones in Mozart's Flute Quartet in D, performed by William Bennett and the Grumiaux Trio (CD, Philips 422 680-2), as vividly as it delivered the slam of Wanda Jackson's "Fujiyama Mama," from Loud, Fast, and Out of Control (CD, Rhino RS 75704).
Want power? The fully loaded Desktop delivered it in spades. Rhythm, too—as illustrated by Mike Stone's vigorous drumming on Tuatara's atmospheric Trading With the Enemy (CD, Epic 68850). In fact, that album was where I began to suspect that something was wrong with my big rig—my desktop headphone system possessed more atmosphere, physical impact, and top-end shimmer than my living-room system, which consisted of about $20,000 worth of separates (at least two of which were undergoing a promised "extended break-in period," but still).
That was when it hit me: I loved the pimped-out Desktop. Not liked or needed or constantly referred to it, but passionately, flat-out loved it. Of course, like most love affairs, this one involved some forgiveness.
Here's what the Desktop doesn't do: It doesn't tell you when you've achieved a digital lock. That's one area where the Grace m902 is much better—its graphic display alerts you that you have achieved a lock with 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, or 192kHz. You can see what you're actually listening to—a lot more important when you're using your DAC in a studio setting, which is where the Grace was designed to be used.