I connected the HeadRoom amp to the tape-outs of my Bel Canto PRe1. Then I wired the speaker lead tail of the AKGs to the Art Audio PX-25. By muting the PRe1, I could cut signal to the tube amp when unplugging the AKG's captive tail from its other half - most SET output transformers smoke under signal without driving a load. No need to risk frying my reference amp. However, the PRe1's tape-outs would still pass signal. By simply hitting mute and swapping leads, I could toggle to the Maxed-Out Home and sample the K-1000s to compare against the tube feed, then adjust volume and compare to the Sennheisers and Grados.

The Max really came to life when I bypassed the attenuator of the Birdland Audio Odeon-AG DAC for its undiluted full bore 2.7V RMS output (7.68V peak-to-peak). When not used amplifier-direct but into a preamp, the manufacturer recommends the Odeon's 3 o'clock attenuator setting. It gives a slightly lower-than CD standard 1.5V RMS output and optimizes impedance for preamp connection. Though the Max retained sufficient output in this mode, the sound became somewhat thin. Feeding it a stronger signal -- and reducing its attenuator setting instead -- significantly fleshed out the music.

The biggest difference between either hookup? Via the Max, things sounded zippier, brighter, with a mild prominence in the upper midrange and sharper, more highlighted outlines 'round performers. With edgier material, this could turn slightly aggressive. The PX-25 packed harmonic meat on those bleached bones. The presentation became far more relaxed and full-bodied. Any former tendencies for some potential stridency sneaking in were abolished.

I need six ears!
Did the AKGs favor tubes as a matter of tonal synergy? Did the Max not possess enough raw drive and thus somehow skew tonal balance? Did it curtail extension at the extremes to emphasize the upper midrange for this whitish leanness?

Yes and no. Substituting the Bel Canto eVo opened up extension in either direction. More drive, more linearity. But by comparison to the PX-25, it still sounded a mite like hornspeakers driven by regular solid-state: Very dynamic, very fast, but somewhat upfront. Eventually, it could get just a bit relentless.

My Avantgarde DUOs absolutely thrive on tubes, and, truth be told, so do the AKGs - at least with the immediate solid-state on hand. With the PX-25, I cherished bona fide Avantgarde performance sans massive horns.

There was their raw sense of startling immediacy as though sounds coupled to the air more directly than via conventional schemes; the superior speed and startling dynamic swings; phenomenal openness; and palpable image density that filled out sonic outlines with bursting color and vibrancy.
AKGs plugged into PX-25 speaker-level; separate feed into Maxed-Out Home;
second 1/4" input for either Sennheiser
SD-600 or Grado RS-1


Everything I love about my DUOs was now accessible in headphone format. However - the AKGs were far more intolerant of lesser sources. And compared to the comfort food demeanor of the Yankee Grados that embrace even modest sources without losing their charm, the German super cans were veritable prima donna prissies. They insisted on fancy Haute Cuisine dining, considered the Marantz CDR-630 a major step-up from the Denon but really only got it on hot'n'heavy with the Birdland DAC. (That explains why I'm finally addressing my front-end weakness. I just purchased a Cairn Fog CD v2.0 24/192 uni-boxer affair. I prefer less rather than more boxes. Review to follow.)

Superior headphones are sometimes -- and astutely -- called musical microscopes. They take the room out of the equation, avoid multi-driver dispersion mismatches and suffer zero crossover losses. They zoom into what's there without dilution or buffering. They are inherently far higher resolution conduits than loudspeakers. And the AKGs are Zeiss optics ruthless truth-tellers. This makes them far more critical than the Grados and Sennheisers. While they have the potential to go places the others cannot, they'll only take you there when ancillaries are up to snuff.

Before I sketch out the sonic bliss that follows when you kowtow to these demands, I must stress that the AKG K-1000s are, single-mindedly, ultra performance devices. They don't suffer casual fools lightly. Unless you treat them with the same respect you accord your dialed-to-the-max main rig, you're better off with the Sennheisers or Grados. The Senns up the ante in the resolution and honesty department over the Grados and, for "normal" applications, are a far saner recommendation than catering to these high maintenance babes.

However. For those intent on scaling the tallest peaks, the AKGs are rare and reliable Sherpas. They image far more like real speakers, except in reverse - the soundstage wraps around your medulla oblongata rather than the forebrain. Stage depth is a function of how far behind your head sounds originate This reads weird only on paper. Once you inhale the pure air, spaciousness and freedom from typical headcase confines, it's hard to go back. Even acoustic solo instruments now stretch out in space rather than being locked dead center in the middle of your skull. The ability to listen into the faintest of details, masked by most speakers and heightened by good headphones, now operates on a higher plateau - magnification squared.

This overall rez effect of speed, subtlety, cubits of air and fine inner detail is similar to Stax electrostats. But here it's ballsier and more gripping, intense in a look-how-many-stars way that night time visitors to the high desert sanctuary of Taos always express. Like the Avantgardes, this kind of intensity (not a tonal forwardness but simple multiplicity of powerful sensory stimuli) isn't for the faint-of-heart who want to drift off. It's for the thrill seekers, the adrenaline junkies of sound orgies.
In this drawing from the owner's manual, you can appreciate the intricate super structure that positions the transducer center of the frame, and also make out the radial magnet sections that power it.
Sweaty ears, space & matters of perspective

Take my old standby for superior female vocals, "Round Midnight" on Carmen Lundy's XRCD release Self Portrait [0005-2, 1996]. The Grados sounded wonderfully liquid in the mids but lacked some of the high frequency shimmer that the Sennheisers bestowed on the sea of violins. This created a texturally drier but timbrally warmer sound - an apparent contradiction only if you don't refer to dryness as a textural phenomenon.

Tonally, the Sennheisers were much closer to the AKGs than the Grados. However, their presentation of texture differed in similar fashion to how the 600s added air over the Grados. Now the Sennheisers stood in for the RS-1s and the K-1000s pulled ahead. The sense of airiness and bloom via their open-air design was in a different league. More importantly, their sense of realism when compared to a first-rate speaker setup was far superior. The Grados and Senns create an artificial intimacy that lets you hear all the right sounds, but still remains divorced from the acute realization of space, venue and perspective.

By comparison, the intimacy of the AKGs seems the real deal. When you think about the binaural hearing principles they exploit, this makes perfect sense (and goes far beyond HeadRoom's electronic crossfeed). There could also be an added psycho/physical factor at work. The Sennheisers create a little cave that seals around your ear. The Grados rest on your ear. The AKGs let your ears breathe freely. These differences operate already in the tactile sensation of physical contact. Personally, I prefer the Grado "touch" over the Sennheisers'. The latter make my ears sweat - literally.

Such impressions are hard to separate from raw sonics. Together they form a set of sensory inputs that combine into the total experience. And while I appreciate the 600s' superior fidelity in terms of frequency response, I prefer wearing and listening to the Grados. (Incidentally, a friend of mine just sent her personal Grado RA-1 wood-body battery-powered amplifier to throw into the ring of my current headphone/headphone amp survey - more to follow shortly.)

On this Lundy and subsequent other tracks, the Grados conveyed more weight and body in the bass than the Senns, quite possibly as a function of their downshifted tonal balance. Consequently, they could be accused of sounding slightly romantic, whereas the Sennheisers strike me as the ideal recording monitor. Bass heft via the AKGs is somewhat adjustable - angle the dynamic panels outwards farther to create more spaciousness and a bigger soundstage. Swivel them in closer to emphasize foundation weight.

The quality of bass, compared especially to the Grados, recalls sealed versus vented alignments - very precise, tight, nimble and fast, but with a bit less weight and mass than the RS-1s that are slightly on the fat/warm end of the spectrum. Slap bass lines snap harder with the AKGs' leaner demeanor while Reggae beats whomp with a heavier punching bag clobber on the Grados.

By settling on enough physical distance to insert my index finger between the ears and the panels' free rear edges, I obtained the most pleasing balance for my personal tastes - between ambient cues and airiness on one hand, and bass slam, HF shimmer and robustness (or image density) on the other. And once I had this aspect licked, there was no going back.

True, the K's benefited from $5K worth of world-class SET amplification. But that's part of their twisted appeal. Being earspeakers with high-level connections, they'll feed on the choicest signal delivery you care to send their way. Of course I'll be the first to admit that $500 ($1,200) phones driven by $5,000 amplifiers are an off-kilter proposition. This merely reflects what I had in-house at the time.
The 4-pin XLR juncture with speaker level leads

Hence I'm presently looking into the Antique Sound Lab offering to dig up something more appropriately priced, say up to $1,500. True, that's still a $2,000 package for the 'phones and amplification, but it'd be a true SOTA rig, with the kind of superior sonics regular speaker systems would easily charge you five to ten times for - if the rooms cooperated. And granted, as good as the AKGs are at creating a three-dimensional soundstage, it's not the same as via standard speakers. But then everything else about the AKGs is far more advanced than most room-compromised speaker setups.

So you see where I'm going. Apply the same stringent quality standards to private listening via 'phones as you do to your beloved main rig -- and granted, not everybody takes headphone listening remotely that serious -- and the AKG K-1000s are true cutting-edge stuff. For now, I'd go with tubes, but likely that comment should be expanded. Perhaps the forthcoming 47Lab Shigaraki op amp integrated, or the Portal Audio Panache? An older Pass Labs Aleph 3 or used Volksamp?

...True cutting-edge stuff...

Does that now make these earspeakers the world's best dynamic headphones? I wouldn't know. What I do know is that they get my qualified nomination for said title - if such a thing existed. And qualified -- in brief recap -- by the need for superior ancillaries and a dedicated amplifier that, unless you don't mind swapping leads or a switch box, will most likely not ever also drive speakers.

Where's that leave us?

If I can find a suitably affordable amp or preamp with copasetic headphone capabilities that mimics the phenomenal Art Audio PX-25 hookup, I will have to send Tyll over at HeadRoom a check for these super cans and make an official package recommendation: For the truly dedicated headphone fanatic wanting a top-level rig that, while dear, won't be insanely expensive. I'll report on hits and misses of this hunt in the saga's next chapter. Stay tuned.