Gramophone Dreams

Feedback issues
I am glad I listened for five straight months without disconnecting the TU-8900's feedback. During that time, I never forgot the feedback was connected, but everything sounded so alive and energized that I never felt motivated to remove it—never, that is, until I began to write this report. When I finally took the feedback out, I was surprised how much rawer the sound became. Without feedback, a deep-and-silent, wet-look transparency appeared. The amp actually got quieter into my 97dB/2.83V/m– sensitive Heretic AD614s.

I found these new, raw, uncorrected sonics quite appealing, especially in the upper octaves and especially on flute, harp, and violin. But at first, despite some effort, I could not grasp what effect the absence of feedback was having on the lower octaves.

I thought my favorite piano recordings would make it obvious, but they didn't. Imagine a hammer hitting a low-octave piano string. A wavefront is produced by that string, followed by a delayed reaction from the sound board; these sound energies combine to produce a complex wavefront, the time alignment of which is critical for full-pleasure listening. Only the best amplifier-speaker pairings get this wavefront alignment right. Push-pull amps need feedback to even get close to preserving this complex phenomenon. Single-ended amps without feedback can capture it, but too often their puny damping factors round the leading edge of bass transients and mute reverb crispness. This is why many single-ended triode amp users like a little "touch-up" feedback to tighten up the bass and make it more tuneful. My Line Magnetic LM-518IA and Elekit's TU-8600S both use such "touch-up" feedback to keep sounds taut and moving fast.

That's why I felt good about the feedback in both the TU-8600S and TU-8900 amps. If you're gonna have solid state rectification, which, generally speaking, tightens and hardens the sound of tube amps, and fixed bias, which has a similar effect, why not wire in a few dB of global feedback to assist the amp in driving lower impedances? I've always felt that these three design choices steered the Elekit 300B amps toward a fresher, crisper, brighter, more contemporary sound than their softer-sounding no-feedback cathode-bias counterparts.

When I first removed the feedback from the TU-8900, I was driving the Falcon Gold Badges. Suddenly they sounded—I can only describe it as weirdly different: inexplicably grainless with a possibly too-dark deep-space transparency that made images look cinematic: very Blade Runner 1982.

I kept listening for chamfered transients or limp bass, but the low octaves seemed taut as ever. Then, a few records later, that darkness I first perceived began changing to brightness and light—sometimes even a slight glare, depending on the recording. The dominant sonic characteristic of the no-feedback TU-8900 was this raw-file, no-glass transparency, which felt unmitigated in some kind of extreme way. A week passed, and the bass was still tight on my Falcons, but I still wasn't sure if I wanted feedback in or out.

And then I realized: What I was experiencing—possibly for the first time ever—was feedback-less 300Bs in concert with the dramatic clarifying effects of amorphous core output transformers combined with the enhanced small-signal conductivity of those silver-foil caps and tantalum resistors.

Sequence is everything (again)
When I replaced the tiny 83dB/2.83V/m–sensitive, 15 ohm Falcons with the barrel-chested, 8 ohm, 97dB/2.83V/m–sensitive, $7290/pair Heretic AD614 coaxials, the no-feedback 300B Elekit experience became more physical and less dynamically restrained. The projected soundspace went from deep and tall to shallow and wide. (I picture speakers as camera lenses, with different speakers generating soundspace effects analogous to changes in aperture and focal length.) The Heretics are sharp-focused but with a shallow depth of field. The bulk of their stout cabinets appears to flatten and broaden the soundstage and reduce the experience of three-dimensionality. Nevertheless, the larger-scale images and the intensity of the Heretics' energy delivery is something I've needed, something I've craved emotionally. For my listening pleasure, I am willing to sacrifice some soundstage depth for image density and what feels like electrified intensity, with singers and instruments presented closer to full size.

The river was whisky and I was a divin' duck ...
I am attracted to the Heretic speakers because nothing else I've been using plays artists like R. L. Burnside in a manner that feels strong enough, textured enough, and tangible enough for this kind of raw musical art. Burnside's 1998 anthology The King of Hill Country Blues: Rollin' & Tumblin' (16/44.1 FLAC, Wolf Records/Tidal) needs big paper cones, fat boxes (and possibly multicell horns) to properly launch his voice and rough-textured guitar into the room.

Without feedback in the TU-8900, the Heretic's 12" paper cones fed me more corporeal energy. As a result, everything felt more impactful, more emotionally fleshed out. Every Elekit 300B virtue was enhanced, especially texture and transparency.

2A3
Western Electric's 300B was used primarily in audio-frequency amplifiers in commercial applications and as a pass tube in regulated power supplies. The 2A3 was the premier console-radio tube of the 1930s and '40s, famous for its clarity and the naturalness of voice reproduction. The Cossor LinLai WE300Bs were my preferred 300B for the TU-8900, but every time I tried the LinLai 2A3s, I'd end up switching to the richer, earthier-sounding 1940s RCA 2A3s (which I sorta collect). In the TU-8900, the RCAs generated more realistic tone and denser body.

In my system, driving the Heretic AD614s, the no-feedback Elekit TU-8900 with the vintage RCA 2A3s excelled at playing Gregorian chant recordings. Playing my beloved "Mare Nostrum" Orient – Occident: Dialogues, a 2011 recording by Jordi Savall, Montserrat Figueras, and Hespèrion XXI (16/44.1 FLAC, Alia Vox/Qubuz), in which Sephardic, Turkish, and Christian chants overlap and complement each other, the sound via 2A3s showcased a coercive intimacy coupled with startling jump factor. I enjoyed how the 2A3 Elekit–Heretic combo played this record in a manner that exposed every drop of Jordi Savall's and Montserrat Figueras's beauty and talent as well as the recording's myriad sonic wonders.

The headphone output
While I'm turning you on to a supervalue SET amp, I may as well give you a quick introduction to a supervalue headphone that I am in the process of reviewing. It's a new model from HiFiMan that, before I knew its price, I assumed was in the $5000 range because it looks expensive and dances sonically with the best: the $1999 Audivina. The 20 ohm, 97dB/mW Audivina is a wood-shelled closed-back with a "NEO supernano" planar-magnetic diaphragm that played crazy clear when powered by the TU-8900's front-panel headphone jack.

I chose the Audivina for this report because I wanted to see how the TU-8900 would drive low impedances and because it was the headphone I'd been auditioning when I started this report.

My ears scanning for problems, I used the Audivina closed-backs to listen to Danza Española played by Andrés Segovia (16/44.1 FLAC, Masar/Tidal). More than with XIAudio's Broadway or HeadAmp's GS-X mini, the sound coming through was vivid and lustrous in a lush, microfocused manner reminiscent of the TAD CE1TX loudspeakers. The beauty of headphones like this is how the amp is connected directly to the headset's raw, responsive full-range drivers with no crossovers or filtering. This allows listeners to experience an unmolested view of the recording. You know how much the purist in me loves that.

Curious, I decided to pause here and put the feedback back in, fully expecting to prefer the sharper transients and better sortedness I had enjoyed for many months. But now the feedback felt annoying, like a politician squeezing my hand too hard when they shake it. Tight is only right when it does not feel like the sound is being restrained or manipulated, and that's the subtle feeling I was getting with every recording with feedback engaged. This was strange in an unsettling way because,

I swear, feedback in the Elekit never felt too tight before I removed it. Once again, sequence is everything.

I left the feedback in for a couple of days to see if my brain would adapt, and it did—a lot. But, ultimately, my artist's spirit preferred the darker, looser Blade Runner aesthetic of no feedback.

Because the TU-8900 sounded authoritative powering the 20 ohm Audivina, I switched the front panel jumpers to a position the manual said would favor my 250 ohm, 96dB/mW Beyerdynamic DT880. I put on "Time Is Tight" and "Green Onions" by Booker T. and the MGs (16/44.1 FLAC, Stax/Tidal) and was disappointed by the disembodied weakness of the sound. Then I remembered that I hadn't used the 880 in months, so I gave it a few hours to loosen up. After that, it felt a lot more solid and 3D playing "Funky AECO" on The Third Decade, by Art Ensemble of Chicago (16/44.1 FLAC, ECM/Qobuz). After some loosening up, the Beyerdynamic sounded enough looser and better to say the Elekit's headphone amp was rocking the high-impedance DT 880s. The modestly priced DT 880's popularity rides on the extreme naturalness of its detail and the correctness of its tone; the Elekit's headphone output honored those traits while adding super PRaT and corporealized textures. I spent the entire night playing every Mississippi Fred McDowell song I could find and went to bed feeling satisfied.

Because I couldn't stop myself, I had to try JPS Labs' stylish, planar-magnetic open-back, the Abyss Diana TC, which, at $4495, cost more than the Elekit TU-8900. The Diana TC is specified as 69 ohms and only 90dB/mW. I believe it is only a click or two less resolving than its stablemate, the Abyss AB-1266 Phi TC. South African Abel Selaocoe playing his own composition "Ibuyile iAfrica," off his debut album Where Is Home/Hae ke Kae (24/96 FLAC, Warner Classics/Qobuz), came through as whole, clean, and exquisitely gold-toned.

The TU-8900's headphone output sounded good, but it got a bit tense and dulled trying to drive the 60 ohm, 83dB/mW HiFiMan Susvara. I'd say 90dB/mW might be a wise bottom limit for headphone sensitivity with this amplifier.

I never thought I'd say this about the headphone output in a moderately priced integrated amplifier, but this one's got the stuff to be all the headphone amplifier most people will ever need.

Conclusion
Over the last three decades, I've enjoyed an enviable cadre of famously expensive 300B amplifiers. I wouldn't tease you with these Elekit stories if I did not believe Victor Kung and Yoshitsugu Fujita had created a uniquely interesting product, one that delivers large amounts of engagement factor, serious tube-rolling fun, and extraordinary sonics at a very reasonable price.