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Brand X Portable Tube Headphone Amplifier Prototypes:[/size]
[size=small]X-Rayed and Enigmatic[/size]
- Description: Portable tube headphone amplifier prototypes.
- Dimensions: 10" W, 2.5" H, 8" D; weight is approximately seven pounds.
- Price: Unknown.
- Manufacturer: Unknown.
Last year I received a fairly mysterious e-mail from someone that simply asked if I was interested in reviewing a headphone-related product -- literally, that's pretty much all it said. I asked some basic questions, he said he couldn't provide any answers yet. A few months later, long after I'd forgotten about the mysterious e-mail, I received another e-mail from the same guy, telling me he had a prototype ready for me to review. "A prototype of what?" I asked -- I mean, I still knew absolutely
nothing about what this product was. New type of headphones? Some sort of processor? A headphone amp? He refused to tell me a thing until I signed an NDA (non-disclosure agreement) -- I kid you not. At least the cat knew how to create a sense of intrigue, asking me to sign the confidentiality agreement, and saying things like, "What I will say right now is that there is absolutely nothing on the market like it."
One signed NDA later, and I was told that what would be arriving on my doorstep was a prototype of a portable tube headphone amplifier, and, indeed, there are exactly zero
portable tube headphone amplifiers currently on the market, to the best of my knowledge. Okay, so it wasn't a teleportation machine; and it wasn't a cure for the common cold (which, given the ear-stuffing, congesting cold I'm sporting as I write this, would be a "headphone-related" invention I'd welcome) -- just a portable headphone amplifier with a glowing vacuum tube somewhere in the signal path. No, I don't foresee a Nobel prize in this fella's future; but, c'mon, if you're a head-fi enthusiast, you know as well as I do that a portable tube amp really is a cool, novel concept.
And so it arrived. I eagerly opened the box, and, true to the guy's warning, the rickety-looking prototype was, well,
not pretty. But he did (and continues to) assure me that the
prototype's outer case was designed to do nothing more than hold the innards in, and to provide a place to mount the jacks and knobs. Even now, when I ask him what it will look like in final production form, he goes back to his secretive ways, telling me little other than that it will be entirely unique aesthetically. I'll try to take his word for it -- some very vague hints he's provided indicate that the final product will indeed be very groovy looking.
The Brand X prototype measred 10" wide, 2.5" high, 8" deep and weighed about seven pounds. It looked more like a mini-component designed to be situated on a desktop or shelf than it did a portable amp, and this made it quite awkward to carry around. The manufacturer assures me the final product, though similarly sized, will not be awkward to tote around -- this I have to see.
The prototypes have what I believe is an internal, rechargeable lithium-ion battery, not entirely unlike a notebook computer's (the press-to-see LED battery strength indicator and notebook-computer-like AC cable lead me to believe that it probably
is a notebook computer battery in there). It has four headphone jacks (unfortunately
mini jacks), each designed for headphones within a certain impedance range -- I believe this multi-jack configuration is something that will make it to production (the manufacturer tells me he is considering offering 1/4" jacks upon request). The only feature I found totally off-putting on the prototypes was the dual volume control, one for each channel. HeadRoom's BlockHead gets away with this for two reasons: (1) it's a
true dual monoblock design, and (2) it's designed to be a stationary amp. Dual volume knobs, however, just don't fit in right with a portable amp's purpose, in my opinion -- portable should be simple. Unfortunately, as with the mini headphone jack configuration, I also believe the dual volume control will make it to final production.
NOTE 12-21-2002: Though the dual volume knob was originally slated to appear on the final product, the manufacturer just notified me that it has been ix-nayed in favor of the more standard single, stereo volume control -- this move gets a big hoorah from this cat.
The RCA input jacks on the Brand X were not recessed. I'm not sure if they're going to be recessed on the final production model, but it would be my recommendation to incorporate a panel that recesses the RCA jacks while the Brand X is being used portably, that could optionally be removed to accommodate larger RCA plugs if and when the Brand X was being used in desktop mode.
NOTE 12-21-2002: Another this-just-in update -- the manufacturer just notified me that the final design will have recessed RCA jacks. He's still undecided on whether or not the amp will incorporate a removable panel to accommodate this -- if it's not too much more expensive to offer this feature, Mr. Brand X Man, I'd suggest going with it.
What's
inside the Brand X? That's something I don't know too much about. The guy must have sensed my deep curiosity about what was in there because he had the dang thing
riveted shut. I do know, per the literature he sent, that inside is one Tungsram ECC88 tube -- and that's pretty much the extent of my expertise on the Brand X's insides. Head-Fi member
Tuberoller actually had the Brand X x-rayed (leave it to Tuberoller to pull this one off), which confirmed the existence of the tube in the circuit; and if Tuberoller (one of our resident tubephiles), after seeing an x-ray of the thing, says there's a tube in the circuit, then there's a tube in the circuit. And I'm pretty sure, eye to the vents, that I can see the faint valve glow inside when the amp's powered up.
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The Sound of X[/size]
How the Brand X prototype sounded is really a two-part affair, as significant modifications were made recently to the circuit to increase gain and maximum output power, as well as to improve bass response. So the first go-'round with the Brand X was sonically a completely different experience than my latest turn with it.
Brand X v1.0: The headphones I used with Brand X v1.0 were Sony MDR-V6 and Sennheiser HD-600. First of all, this first version of the Brand X did not exude a bit of the euphony often associated with a "tube sound". In fact, it provided a quite neutral tonal balance, particularly from the mid-bass through to the upper regions. Lower bass was good, with moderate oomph, if not the near-standard-setting bass solidity of my HeadRoom Max -- one might never feel anything was lacking in this regard if he didn't have something like the Max sitting right next to it.
One thing I found the Brand X v1.0 to particularly excel at was the more delicate percussive textures. I feel mildly qualified to comment on the realness of recorded drums, as I grew up with a drummer brother (our very own Head-Fi engineer, Neil); and the delicate snare drum on Dave Matthews Band's
Crash title track was very alive, with at least as convincing snare-ish snap and sheen as my HeadRoom Max, and maybe even
just edging it out in this regard.
The Brand X v1.0 was a nimble sounding amp, with impressive microdynamic detail conveyance. Macrodynamic performance, on the other hand, was its weak point, the Brand X v1.0 sounding a bit anemic when pushed by the likes of the explosive track titled "The Battle" on the
Gladiator motion picture soundtrack. When listening to this track at moderate to loud volume levels, the pyrotechnics of the orchestra was quite stunted when compared to the Max. "The Battle" screams to be unleashed fully, but the Brand X v1.0 kept too much of a rein on the excitement. The same thing happened when playing the dynamically dramatic "Polka and Fugue" on the XLO Test CD, the Brand X v1.0 coming off as quite a bit too geriatric in its willingness to crank it up when absolutely needed.
Head-Fi member KurtW (one of our resident META42 builders, and Corda-modder extraordinaire), feeling a little John Atkinson-ish during his turn with Brand X Beta v1.0, took some measurements of the amp, and found the frequency response was
"down 1.5 dB at 100 Hz, 3.7 dB at 50 Hz and 7.4 dB at 25 Hz. It was within 0.5 dB between 200 Hz and 12.5 kHz, and only down 1.3 dB at 20 KHz. The ZOTL, in comparison, is only down 0.2 dB at 20 Hz and 20 KHz." However, KurtW did also say that he did not find the Brand X Beta 1.0 to
sound bass-shy. Seemingly vexed by these measurements, Mr. Brand X Guy wanted it back to have it measured and, if necessary, adjusted. And that's just what happened; which brings me to....
Brand X v2.0: The headphones I used with Brand X v2.0 were Sony MDR-V6, Etymotic ER-4S, AKG K240DF, and Sennheiser HD-600. Though it arrived clad in the exact same rickety-looking prototype casing as Brand X v1.0, the updated internals made for a wholly different sounding amplifier than the v1.0, and I liked it significantly more than the original.
First of all, v2.0 seems to be sporting some seriously stepped up output power, clearly able to play louder than v1.0, and getting loud without sounding strained (with the exception of one particular headphone -- I'll get to that in a bit). More importantly, macrodynamic performance is helped heaps by whatever changes led to this -- "The Battle" sounded more deserving of its name, and "Polka and Fugue" rediscovered almost all of its intended pomp with the v2.0. Though it doesn't have the most charged macrodynamic capabilities I've heard, it was still quite impressive, and, again, loads better than v1.0.
Bass impact/extension was also turned up a noticeable notch, making the v2.0 significantly more rhythmically enjoyable than the v1.0. The genius of Edgar Meyer's virtuosic double bass performance in "Caprice for Three" from the
Appalachian Journey SACD is more easily appreciated through the v2.0 than the v1.0. However, compared to my HeadRoom Max, the v2.0's bass control is a little looser, making Michael Arnopol's audiophile reference bass fusillade at the beginning of Patricia Barber's "Use Me" on her
Companion album sound less precise than I know it can sound, and so a little less real around the edges. Outstandingly well-controlled
deep bass extension is one of the hallmarks of the HeadRoom Max, and, with several albums I tried with thunderous low bass, the Brand X v2.0 subjectively falls short of the Max's extension, and well short of the Max's control, in this region.
Like the v1.0, the v2.0's treble extension and presenation is excellent, and might not be what one might expect, considering tube amplifier stereotypes. In fact, the v2.0's treble presence is a little stronger than the very smooth, solid state Max. Though the v2.0's treble is more prominent than the Max's, I feel it's very important to emphasize that the v2.0 is still very civilized in that region, never giving way to treble ringing or tizz. As a matter of preference, I generally prefer the Max's smoother upper register due to my ears' sensitivity to treble frequencies; but I will admit that there are some warmer recordings better served by the v2.0's presence in this specific region.
The v2.0's overall tonal balance reminds me of the several Antique Sound Labs MG Heads I've owned, only with much more impressive bass performance. Its detailed, nimble midband is immediately endearing, and its neutrality through this range makes for lovely reproduction of both male and female vocal performances. The Max is quite neutral through the entire midrange with crossfeed off, but, with crossfeed on, the Max can come off a touch too chesty with some deeper, already-chesty male voices. The v2.0's low register solidity and increased output power -- combined with the v1.0's excellent midband performance -- make it
significantly more enjoyable to listen to than the already-good v1.0. Long story short, the v2.0 is everything the very good v1.0 wanted to be, but with more gusto.
One area that both the v1.0 and v2.0 do exceedingly well in is soundstaging. Both cast wide open, airy images -- wider than the Max. However, I still prefer what I consider to be a more cohesive, more natural and realistic soundstage that crossfeed provides versus non-crossfeed headphone listening, and the Brand X would be of even greater interest to me with an effective crossfeed option.
Unlike the v1.0, the v2.0 rarely ever sounded strained, and could reach extremely loud volume levels with every headphone I plugged into it, save for one -- the AKG K-240DF's. I've found the K-240DF's to be generally challenging cans to drive for some headphone amps, and the v2.0 did a so-so job, sounding competent at louder volumes with these headphones, but just barely. Already a thinner sounding headphone to my ears, the K-240DF's were almost completely devoid of body when driven by the v2.0. For all practical purposes, this didn't concern me one bit, as the K-240DF's are not on my list of regular listening phones, but I thought it might be worth mentioning for some.
One of the most difficult parts of this review is coming to any key conclusions about value relative to competitively priced units, as I have
no idea whatsoever what its price point will be, or even a general range. Conversations with Mr. Brand X seem to suggest to me that it'll be anything but inexpensive. I've since had an opportunity to briefly live with a HeadRoom Cosmic Reference, and I think anyone who's heard one will agree that it may very well be the best portable headphone amp on the market right now. At $800+ in its tip-top form, the Cosmic represents a very expensive portable headphone amp, but it is also capable of bringing home the sonic bacon as a desktop amp against many of its desktop-only rivals. I hope to one day be able to compare the Cosmic Reference and Brand X v2.0 head to head. If the Brand X v2.0 is priced in the range of the Cosmic Reference -- and maybe also given a somewhat more manageable portable form factor than the Brand X prototypes -- then I think it could be a
very strong competitor (the addition of crossfeed would make it a stronger competitor still). If it's priced any higher than that, I think it might be a tough sell. At the end of the day, it will probably be the only available portable tube amp when it comes to market, and, priced right, that might be all it needs to reach Mr. Brand X's sales goals for this product.
Pluses: Will almost certainly be the first commercially available portable tube headphone amplifier available if it's released soon; prototype seemed durable (it had been shipped around a lot, but always worked); ability to provide solid bass grunt; nice sense of neutrality; good frequency extension in both directions; timbrally impressive; good soundstaging; can drive just about any headphone you're likely to plug into it quite well; though a tube amp, it ran quiet, and also cool to the touch.
Minuses: Conversations with the manufacturer hint at a relatively high price point (if this ends up
not being the case, I'll edit this out of the "Minuses"); though portable, its form factor in prototype stage was more awkward to carry than the Cosmic (even with the Cosmic's 4-D pack); minijacks for headphone outs (I'll keep this in the minus column until I receive confirmation from the manufacturer that 1/4" jacks will be available); no crossfeed; bass control could use some firming up; still an enigma after all this time.
