With the last direct-heated power triodes on my speakers going back a few years, I wanted context to revisit this scene. As chance would happen it, Allnic's A-311M PX25 monos touched down just then. At $13'900/pr, they simply played in the double+ league. Whilst designer Kang-Su Park offers them in AD1 and 300B versions, each gets interstage and output transformers custom-tailored to the power triode the client stipulates at purchase time. There's no rolling between different types, just alternate vendors. Hence bias is automatic/fixed. My South Korean samples were fitted with pricey NOS GEC PX25 and GEC 5U4G.

Having for the Tektron determined quickly that paralleled PX4 for twice the power got somewhat fuzzier without alternate benefits into these loads, its comparative 4V tube complement became just two power bottles, one per channel. This was my closest apples-for-apples attempt. The Allnic were preceded by our transistor Wyred4Sound STP-SE II line stage operated in passive mode without voltage gain but with active buffers on the i/o for linear impedance regardless of volume.

With its hum pots optimized, the Tektron exhibited the same low but not fully absentee electrical noise as the Allnic. The Polish 10" widebanders betrayed very faint hum audible up close but not from the chair. With Allnic's published S/NR being -76dB, Tektron's seemed equivalent. It'd mean ~13 bits of resolution; 7 bits less than our DAC, preamp and high-power transistor amps, 3 less than CD's Redbook standard. Like yours will be unless your gray matter were temporarily replaced by a calculator, spread sheet and scope, my ears were solely concerned with sonics. And those spoke of very different things.

Not knowing where on the global table SETting the Allnic belong, I can only report that the Koreans were heavier in the bass and somewhat darker across the bandwidth. On subjective damping—whether recorded venues feel more live or dead, more reverberant or damped—the Allnic's PX25 or output transformers exerted more. By degrees,  this rendered things more dry and taut, less fluid and elastic. In the upper midrange/lower treble bands, the Tektron behaved more dynamic and lively, hence separated out more cleanly. This benefited faintly tickled cymbals and such. As a result, the Sicilian also had the tunes feel a tick faster where the Allnic moved them along more leisurely. Compared to our usual FirstWatt SIT-1 transistor equivalents, both DHT versions showed clearly twitchier microdynamics. On Jazz piano for example, a Norwegian player's deliberate spiking of certain notes within a melodic arc was more acute. Standing out like taller forgotten blades of grass at a just-mowed lawn's periphery, these accents added rhythmic spice with stronger syncopations.

Having compared the PX4-fitted Tektron to Reinhard Thöress' €14'000/pr single-ended Mosfet hybrids with tube voltage gain and tube buffer, I knew how by contrast, the full tubes' bandwidth extremes were softer to emphasize/elevate their midband. I knew how the hybrid's lower noise floor more strongly illuminated recorded space, including those quasi halo or sound-bubble effects around performers which light up the space around them. But relative to moving through time—what I think of as music's gait, its poise or how it walks—the pure tubes were also the even more slinky and texturally billowy.

If we drew a line and placed the SIT-1 far left for one polarity, the Tektron far right for the other, the Thöress would sit halfway between middle and far right; the Allnic halfway between the Thöress and Tektron. This line represents the continuum from damped, taut and dry on the left to fluid, mellow and fluffy on the right. Here the hard-right Tektron was the hostess with the mo(i)stest. Recognizing this flavour from a past encounter with Vinnie Rossi's DHT spud module for his Lio platform, I think of it as the quintessential appeal of direct-heated no-feedback triodes maximized to express it. It's inherent that robotic 21st-century music styles with their drum machines and jack-hammer synth bass undergo quite the attitude adjustment. Whether you find that makeover or gait change attractive or somewhat alienating is purely personal. True regardless is that on color pop and tonal meatiness, these triodes painted with a deeper richer more vibrant colour palette than our best transistors. Because their treble was softer and their ambient recovery less keen, this emphasized physicality and hereness, not thereness aka virtual teleportation to a venue other than our own. Given the grand price differential and far greater functional flexibility versus clearly commensurate sonic quality, I will end this page by saying that the Tektron would have my vote if I had to decide between it and the Allnic monos. Which gets us to the fun part of this assignment: tube swapping.