When I first agreed to review the Brand X headphone amplifier, I was very eager to receive it, and anxious to get started…believing that I would be able to give a fair, unbiased review of it’s strengths and weaknesses. Now I’m not so sure (about the job I’m able to do). The reason? I had assumed that, being a tube amplifier, the sound of the “Brand X” would be distinct, with some of the syrupy sweet “tube warmth” that we who love tubes (and yes, I AM one of “them”) appreciate. Well, TO IT’S CREDIT the Brand X amplifier has none of that tube “personality”. From purely a sonic point of view, it seems to have no personality at all. And perhaps that’s the kindest thing that can be said of a component whose job is simply to amplify, WITHOUT CHANGING the sound that passes through it. This Brand X does magnificently.
The Brand X is one of the least “colored”, most “neutral” pieces of audio gear, tube or solid state, which I’ve ever encountered. This delights the purist in me. But I must admit that the tube lover in me was a bit disappointed, as I can point to absolutely nothing as being “tube-like” in the sound of the Brand X. It is supremely NEUTRAL. More so in fact than most solid state headphone amplifiers. Take the models from Headroom, for instance. Headroom products have a family “sound”…warm, “glowing”, with slightly rolled-off extreme highs. Compared to my “Total Airhead”, the only portable headphone amp which I own, it is the “Total Airhead” which to these ears sounds more “tubey”. It also is the “Total Airhead” which is the most “colored”, the Brand X simply passing the signal through (with gain…more comments about which later) without adding any editorial commentary on how the music being reproduced should sound!
When I first unpacked the “Brand X”, I plugged in my Philips Expanium 203 portable cd/mp3 player (with Radio Shack gold plated cables) into the Brand X, and fired up “Don’t Worry Baby” by the Beach Boys, a long-time favorite. Admittedly neither the recording, nor the source materials are “audiophile approved”, (although I think the Philips portable is a completely reasonable companion to a supposedly “portable” amplifier) through my Sennheiser HD-580 headphones, plugged into the 250-400 ohm jack, the sound was wonderful…. Sounding JUST AS this same recording does through the headphone amplifier of my Yamaha MD-8 digital workstation, and the (excellent headphone section of the) Mackie 1604vlz, a console noted for it’s superb headphone amplification.
Interestingly I got far better results (in terms of dynamic “punch”), and noticeably more gain when using high impedance ‘phones such as the HD-580, HD-600, and Beyerdynamic DT-990 Pro than when used with lower impedance, generally more "sensitive” ‘phones such as the Sony MDR-7506/MDR-V6 and Grado SR-80. Interesting, and quite unusual!
Criticisms? I have a few. First of all gain. I’ve been assured that the production model will have “twice as much gain” as the unit supplied for review. A good thing! For several days after first using the prototype Brand X with my MDR-7506 ‘phones, I referred to it as the “straight wire WITHOUT gain”. Honestly, gain was very nearly unity (NO gain) when feeding the 7506 from the output of portable CD players, mp3 players, and portable MD and DAT units. GIMME SOME GAIN, PLEASE! (Again, I have been assured that gain will be a non-issue in the production model. But I leave this observation in because it was of concern to me with this prototype!)
Just three more “nits to pick”. First of all, I’m not a fan of dual (separate left and right) volume controls. I understand the purist ideal of keeping channels as separate as possible. Blah, blah, blah. I still say…”Give me a single STEREO volume pot, and if you really feel generous, a balance control, too.”
As for the internal rechargeable battery, frankly I don’t give a damn. There’s no way I’m going to carry something this large (about the size of a typical “1 rack space” piece of rack-mount studio gear) as a portable, so I simply don’t care about the battery power. Didn’t use it (except to confirm that it works), and wouldn’t.
And the final “nit”: if absolute transparency (with no audible coloration) was the design goal, as it obviously was with this unit, why use a vacuum tube at all? Yes, I realize that any level of sonic accuracy that’s achievable with solid state devices can also be achieved in “hollow state” designs. It just seems (to me) that achieving these results is more difficult with tubes, and can result in products which are less stable, and less reliable. Wait, didn’t I say I was a tube-lover? Yes, I certainly am! But I admit that my favorite tube designs are the ones that actually sound like there’s a light show going on “under the hood”. For many years I used an early 60s vintage Fisher tube amp to drive headphones simply because of the “warm, silky smooth sound” of tubes, with the expected “liquid midrange”, “sweet highs”, etc. Colorations? You betcha! Which is why I would NEVER use a tube amp for monitoring in my studio. Except, perhaps, for the Brand X. because it DOES NOT color the sound, as do other tube amplifiers. Whether this neutrality (in a tube design) makes you more or less likely to buy the Brand X (when available), only you can decide. I DO like this amp very much, and anxiously await the finished product, which I WILL evaluate for possible inclusion in my studio (as opposed to my home or portable systems). It’s that good! Enough said!
I shall end with a technical description of the unit, “lifted” from the literature supplied to me with the amplifier:
First a description of the unit. For that, I defer to the literature provided to me with the amp:
Headphone Jacks: The four headphones jacks have the following impedance ranges: 20-40, 100-250, 250-400 and 500-700. You may find that certain music will sound better when using a jack other than the one for which your headphones are rated. Experiment, you may be surprised.
Technical Stuff
· Input impedance: 25K ohms
·Input volts for maximum power output: 1V RMS
·Maximum power, from any output jack into a matched load: 25 milliwatts
· Triode design
· Incorporates components by Allen-Bradley, Electra-Print, Westcap, and Spectrol
· One NOS Tungsram ECC88 tube – Made in Hungary in the 1970’s, this tube provides the warm tone, wide stage, and coherence we like. During production, alternate tubes can be installed upon request.
Mike Walker Owner/Operator “The Production Room”
Host/Webmaster “The Production Room Dot Net”
Air Personality “Ninety Five Point Seven, ‘XRC” in Charlotte, NC
). This case is, as I understand it, nothing like the production case that this amp will come to market with. Though there will be some technical adjustments made to the amp, I believe the circuit of the amp we evaluated will be very similar -- if not identical -- to the production model.
