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Positive Feedback ISSUE 54
march/april 2011


The Woo 22 Headphone Amplifier, the Whiplash Audio Dynamics TWag v2 Balanced Headphone Cable and the Sennheiser HD800's: Could This Be the Ultimate Headphone System?
by Andy Schaub


There was a boy
A very strange enchanted boy
They say he wandered very far, very far
Over land and sea
A little shy
And sad of eye
But very wise
Was he

From "Nature Boy" by Eden Ahbez

In the future, everyone will listen to two-channel sound systems for fifteen minutes. Then they will return to their iPods and hopefully use something besides the dreadful earbuds that come by default with the iPod; but perhaps a few happy souls ("we happy few"—"Henry V" by William Shakespeare) will turn to their CD players, digital music servers or—yes by golly it just might happen—to their turntables and play vinyl records. If all that comes true, when we live in storage-closet sized apartments as in "The Fifth Element" by Luc Besson, I really, truly hope that those people will use a Woo 22 balanced headphone amplifier ($1900) with the premium tube upgrades (check the Woo site for pricing on the various tube upgrades), the Whiplash Audio Dynamics TWag v2 balanced headphone cable, and something like a pair of Sennheiser HD800… or perhaps the HD650's if one prefers a lusher, more proximate sound. Pardon me for that interruption. I had to flip Brothers by The Black Keys from SIDE A to SIDE B on the Rega P3-24 in my home office while listening to this truly excellent LP via said headphone system (in this case with the HD650's featuring an Audio Note IQ3 moving magnet phono cartridge, Audiomat Phono 1.5 phonostage and all Audio Note AN-V and Kondo Sound Labs KSL-LP interconnects running passively through my Triode Audio Corporation TRV-88SE KT88 push-pull integrated / power amplifier).

Now the Woo 22 with the stock tubes is no slacker; I let the TWag v2 headphone cables and HD800's burn in by continuously playing for the better part of two weeks before I upgraded; and believe me, I had no complaints. However, that was after I had done the following…

Power tubes upgrade:
Sylvania 7236 NOS 1963
Handpick matched pair

Driver tubes upgrade:
Handpick matched pair
Shuguang Treasure CV181-Z / 6SN7GT

Rectifier tube replacement:
Sophia Princess Mesh Plate 274B rectifier

So to say I felt impressed would represent an understatement. They completely blew me away; I am not talking about that "high-fidelity" sound that sometimes comes with upgrades where everything gets spread a little farther apart and you hear more "air and space" around the instruments which entertains you for about ten minutes. No, I mean my HD800's sounded better: more real, more like music and for the first time in my long-term love/hate relationship with them, I did not feel that the music sounded overly spacious as if the performers had been recorded with the Blumlein Configuration (known for its ability to capture the space around the instruments) in a vast French cave. Nor did I feel like I was on stage with the performers, àla my Spectral and heavily-modified Quad ESL-63 system from the mid 1990's. I felt like everything sounded just right… even after I put in the Kondo KSL-LP interconnects. In fact, I felt so impressed with the sound that I ordered a Taburet M Stacking Stool from Design Within Reach so I could swing around and put my feet up at my desk while listening to music via the Woo 22. It captured my imagination that much.

Before I get carried away, let me say that I did try the same arrangement with the Moon Audio Silver Dragon V2 balanced headphone cable and, no, it did not have the same presence. Which is not to disparage the many fine Moon Audio products I have recommended, it's just that in this case the Whiplash Audio Dynamics TWag v2 definitely tied things together with a level of synergy that kind of scared me? I also tried it with both the HD800's and HD650's, and in my portable system with a 160GB iPod Classic, a Ray Samuels SR-71B and a pair of JH Audio JH 16 Pro's, albeit with the Silver Dragon V3 LOD (Line Out Dock), all with the same effect. In fact, I liked it so much that I ordered a pair of TWag v2-modified Ultrasone Edition 10's and TWag v2-modified Beyerdynamic Tesla T1's, both balanced, along with a TWag v2 balanced to single-ended (1/4" stereo phone plug) adapter.

main system

Now for those of you who don't understand the difference between "balanced" and "single-ended" headphone cabling, let me try to explain it in lay terms (the only way I can explain it, myself a lay person). A "normal" or single-ended signal uses two wires; one normally called "hot" which carries the musical information as an analog waveform and one called "ground" or sometimes "return" which allows for a complete connection in the circuit which is essentially one large circle of power. As the voltage in the signal goes up, the headphone diaphragm moves more and vice versa, thus creating pressure waves in the air that corresponds to the analog waveform carried in the wire, which corresponds in turn to the original pressure waves in the air we call music. In a balanced system the same thing happens except that there are three wires: two hot which are perfectly out of phase with each other combined with one ground. When the signal arrives at the headphones, one half of the hot "pushes" and the other half "pulls" as in the diagram that follows:

½ signal → <diaphragm> → ½ signal

Because the signal halves are perfectly out of phase, they provide more support to the diaphragm and cancel out any noise picked up along the way from some point in the headphone amp, or earlier if you have a completely balanced system, to the headphones. In short, all the signals get perfectly added up in kind of "push me pull me" configuration that has less noise and (I think) better bass and treble. This last point is of course implementation-dependent and doesn't apply to every stereo system just, in this case, to the Woo 22 headphones amp.

The abundance of tubes makes the Woo 22 headphone amp quite pretty to see not to mention extremely musical as well having an extraordinary amount of craftsmanship put into the fit and finish of the amp. I should also comment that Jack Woo makes the prettiest metal headphone stands that I have ever seen that, as with his amp, are quite solid and just have a sense of old-world craftsmanship to them.

woo stand

While I was examining the insides of the Woo 22—with Jack's permission—I used my HD650's with the TWag v2 headphone cable and the balanced to single-ended adapter I mentioned going into my Triode Audio Corporation TRV-84HD 6BQ5 single-ended stereo headphone and integrated amplifier. The remarkable thing about the TWag v2 is that it allowed the HD650's to compete favorably with my reference AKG K701's modified to use about 15 feet of Audio Note AN-SPx speaker cable which, at last count, cost at least $1K per meter; and believe me, the TWag v2 costs nothing like that and is in many ways prettier and more flexible. So even if you don't buy the whole Woo 22/TWag v2/HD800 combination—although it is a lovely combination—consider getting the TWag v2 alone for whatever headphone setup you do have. I use it with my Ray Samuels SR-71B portable balanced headphone amp along with a black 160GB iPod Classic and a pair of black JH Audio JH 16 Pro's; and when I use this setup, I listen to a lot of Johnny Cash. In fact, Whiplash Audio is coming out with a translucent black version of their TWag v2 cable which I imagine would look very elegant with my Beyerdynamic T5p's; often used with the iPod/SR-71B combination just mentioned.

tri amp

One aspect of the Woo 22 balanced headphone amp I should mention is the utterly superlative quality of its Teflon tube sockets, which grip the tube pins perfectly and make a flawless electrical connection between the amp and the tube; they are works of art and deserve special mention and high praise on their own. While I do not understand how he has done it, Jack Woo (an extremely kind and generous fellow) has managed to create true synergy in designing and building the Woo 22 balanced headphone amp which, with the premium tube upgrades, presents the most effortless, immediate presentation of sound I have heard from any headphone system, or perhaps any stereo system. Again in conjunction with the Whiplash Audio Dynamics TWag v2 balanced cable and Sennheiser HD800 headphones, which all manages to look lovely together, too.

I should mention that shortly after I finished this article, my TWag v2-wired Ultrasone Edition 10's and Beyerdynamic Tesla T1's arrived, both of which sound excellent. However, I have to say that the Edition 10's modified with balanced TWag v2 cable running into the Woo 22 with all premium tubes really stunned me with its naturalness, so much so that I actually imagine that they will become my new reference. The HD800's have a little more air and space; the T1's have a slightly lusher presentation, but the Edition 10's sound, "just right".

Kindest regards,


Woo Audio

Whiplash Audio