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Massively paralleled. Wearing highly resolved beyerdynamic T1 whilst plugging more and more headphones into the parallel ports, I keenly checked for any sonic fallout the Ts might telegraph from sharing output voltage with up to three other cans. It was a bit hard to swallow that absolutely nothing untoward happened though I wouldn't get jacked up on four simultaneous HifiMan HE-6. With my headphones on hand I couldn't poke a hole in Ken Ball's claim that their machine is load invariant. Again, I fail to see the practical relevance but this feature works exactly as stated.


Glowing regulators. Thinking folks are hip to a general fact. Music signal modulates the power supply. Particularly with amplifiers this creates direct linkage between PSU quality and sound quality. Valve fans are equally hip to the influence a driver tube has on the performance of the often flashier output glass. Here a prime example is a 5687 driving a 300B. The latter gets all the attention. Fewer appreciate that a 6SN7 or EL34 or C3m driver would make that famous DHT sound quite different. By the time we get to expectations for sound effects from regulator tube swaps—very few valve circuits use 'em—most would probably shrug it off as not even being in the signal path. All the juicier then to try. As though vying for a pop quiz answer, the Raytheon alternates glowing a very bright orange sounded just like they looked - more lit up and intense. Using Hüsnü Senlendirici's clarinet as 'my' instrument accompanying singer/cümbüş player Cem Yildiz, this effect was clear as day and very attractive. Background-mixed sound elements gained in coincidence with foreground stuff for more even weight distribution.

The uncontested max-glow option.
 

The inescapable upshot? The beast is a tube roller's delight. Every bulb on deck is a tuning device. I couldn't in good conscience select one station as more important than another though on magnitude I'd probably call the rectifier last in line at least based on the two options I had on hand.		  
Mondo (e)recto. Replacing the stock JJ GZ34 rectifier with one of my remaining high rise EML 5U4G had a 2M effect. Things got mellower yet meatier. The stock recto was slightly edgier and leaner by comparison. 6V6 swap. Rolling out the TAD-branded 6V6 and rolling in some NOS JAN—joint army navy—Philips intensified color temperatures and tone density. 6SN7 swap. Plucking the Russian Tung-Sol reissue 6SN7 stocker and sticking it to another NOS JAN Philips variant left over from my long-departed Wyetech Labs Jade preamp made the sound more intimate. Pole dancer escalated blood flow to lap dancer. These 6ex vibes of the shifts induced by the 6V6 and 6SN7 moves had to do with relative soundstage width and lightness slash fluffiness versus greater central focus and fullness or weight. The vintage bottles were heavier, wetter and more downward ambitioned. The current production alternatives were lighter, drier and more upwardly mobile. The former gravitated mass between the ears, the latter redistributed some of it laterally to feel wider and airier.


What surprised me completely was the regulators' impact on perceived tonal balance where the apparent signal-path bottles frolicked predominantly in the textural playground. Unless you deal in hot-swappable/socketed opamps like Asus promotes with their Xonar Essence Once, this type of tweaking isn't possible with transistors. It's thus an intrinsic feature of the Studio Six which belongs on its core spec sheet as a vital attraction. Think polyroly!

Deep-sixed. The ST-6 is the kind of device which requires serious writer discipline to not slight it with a sloppy hence lazy ode to orgasmic delights in the aural red-light district. The combo of modern resolution—such low noise floor from six valves is serious engineering—er... mated to linear bandwidth with real cojones and a clear tendency for voluptuous density and blood & sweat meatiness evokes all manner of seductive descriptions. John Darko called it pure poetry. Michael Mercer's wife called herself the headphone widow ever after hubby plugged himself into the Six. If you compare this review to the one we did for Bakoon, the different verbal tenor is plainly obvious. That discredits this less factoid-centric take with the objectivists but it's the only appropriate approach.
My ultimate six: Philips NOS JAN 6SN7 and 6V6, Raytheon OB2, EML 5U4G
Ultimate six. At the end of the day that's at the very heart of this thing. Done properly like Audio Line Out did, valves can appeal to the emotions in ways which are arguably more direct. It's as though they bypassed the analytical frontal lobes and ingratiated themselves with the older more primitive part of our brain. We could argue until the cow comes home—an actual annual occasion in Switzerland—about the why and wherefore. Let's leave that to the academics. In audio terms the transitorized Bakoon eclipses the already very good Studio Six on pure magnification power to be an ultimate hi-rez device without any pixilation artifacts. It's the hear-everything maxime done to perfection. Yet the listening experience with the valve amp is no mere second. It's fundamentally different. It addresses and satisfies another human receptor mechanism. It's the Timothy Leary credo of turn on, tune in, drop out implemented as an electronic circuit. For a suitably juicy departure sentence, it's the Men are from Mars, Women are from Venus affair. Except that with the Studio Six, it's the men who finally get to be from Venus...
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