Gramophone Dreams #51: Feliks Audio Arioso amplifier & the Western Electric 300B tube

From my writing chair, I can see about a dozen moderately priced tube and solid state audio amplifiers.

The five stacked next to my desk are First Watt or Pass Labs models designed by Nelson Pass. Across the room is a hybrid tube/class-D Rogue Sphinx V3 integrated. That black Sphinx is standing on its side behind one of the DeVore Fidelity Orangutan O/93 speakers. Next to the Orangutan is a Schiit Aegir. The most conspicuous amp in the room is my BFF, the Line Magnetic LM-518 IA (footnote 1), which breaks the night's darkness with its tall, bright-emitter 845 triodes. Next to that is Ampsandsound's Bigger Ben KT88/6L6 single-ended speaker and headphone amp.

Behind the Ben is the made-in-Japan Elekit TU-8600S single-ended 300B kit-amp. In the shadow of the Elekit sits the stunning (but humble) 2.3W Decware 25th Anniversary Zen Triode amp.

Stage center is my reference high-power solid state amp: the Parasound Halo A 21+. The black, monolith-like Parasound is installed on a Harmonic Resolution Systems M3X-1719-AMG GR LF isolation platform and is connected directly to the wall outlet by a thick, stiff, 1m length of AudioQuest Tornado power cable.

Next to the A 21+ sits the new, made-in-Poland, $6499 Feliks Audio Arioso, the stereo, single-ended 300B amp that I am about to describe in some detail (footnote 2).

But, before I do that, I am impelled to tell this brief warmup story.

For two weeks, I'd been listening to old-time country blues, mostly from collections by Harry Smith and Alan Lomax. I was listening with the Falcon Gold Badge LS3/5a's powered by the Parasound A 21+. This system's dramatically articulated sound was doing all the work, leading me excitedly from one artist or track to another. Rarely had my favorite kind of music felt more exciting or important.


Then, a few days before my deadline, I thought, "Dammit, I should get that Feliks amp into the system, give it some warmup time, and get my ears retuned to single-ended, 300B sound."

Inspired, I hit pause on Turner Junior Johnson's "When I Lay My Burden Down" from The Land Where Blues Began – The Alan Lomax Collection (16/44.1 FLAC Rounder/Qobuz) and exchanged the 300W (into 8 ohms) Parasound for the 300B Feliks Arioso, which is rated at 8W.

When I restarted that Turner Junior Johnson tune, I started mumbling "What the hell? Are you kidding me?" I was shaking my head in disbelief at how radically different the music now sounded. With the Arioso, the pitch of Turner's voice seemed to have dropped half an octave. His growl was now rougher and darker and thicker in texture.

But what really got me was how Turner appeared to be directly there in front of me with a definite tangible human-ness that I did not notice with the Halo A 21+. The Arioso appeared to recover some extra amount of low-level information (picked up by Lomax's microphone) about Turner Junior Johnson's physical body and movement. This new information was extremely subtle; it seemed I could feel Turner Johnson's personality, there in the room, near me. Art Dudley alluded to this "human presence" in his Jeffrey Jackson/Experience Music report. This newly discovered fleshy peopleness impressed me, excited me, and strengthened my connection to one of my all-time favorite songs.

Sporting Electro-Harmonix EH Gold 300Bs, the Feliks amp did not sound warmer, fuzzier, blurrier, more distorted, or more euphonic than the Parasound. It did not emphasize the midrange or roll off the frequency extremes. It was simply more transparent to what Alan Lomax had recorded.

Feliks Audio Arioso
When I hoisted the Feliks Arioso's black-powder-coated chassis from its inner box, it seemed twice as heavy as its specified 39.68lb (and it was! It weighed 68lb on my bathroom scale). According to my ruler, the Arioso measured 15" wide × 8" high × 18" deep. Viewed from above, it possessed an unusual, distinctly masculine stealth-bomber aesthetic.

The Arioso's tube complement is anchored by a tank-sturdy NOS Russian 5C3S (5U4G-type) rectifier tube. It features two octal-base Psvane CV181 MK2/6SN7 voltage-amplifier driver tubes and two ceramic-base Electro-Harmonix EH 300B Gold output tubes. The extra-firm "gripping-of-the-pins" I experienced while inserting and removing these tubes indicates that the Arioso uses top-quality tube sockets, mounted to the chassis.

The Arioso's distinctive, matte-black chassis sits on four sturdy vibration-absorbing footers, but inside is where its true beauty resides. Like all Feliks amps, the Arioso is point-to-point wired and looks and feels (to me) like it was built to sound good and last forever.

Kevin Deal of Upscale Audio, Feliks Audio's American distributor, wrote to me in an email: "The Arioso's power and output transformers are designed and manufactured in Poland by Edis Ogonowski." He told me that the Arioso uses "Caddock and carbon film resistors" and that "part of the Arioso's magic is from using rare Soviet-era PIO K75-10 capacitors in the power supply. These oil and paper caps are cherished by the DIY crowd in Eastern Europe, and Feliks has a large supply of them." (I use the same Soviet capacitors in my DIY amps.) "In addition, they use Red Jantzen coupling capacitors."

In contrast to my Elekit TU-8600, which has only one input, the Arioso is a legitimate integrated amplifier by virtue of its three line-level (RCA) inputs, which are engaged using Japanese-made Takamisawa small-signal relays. The output level is set via a motorized RK27 Blue Alps volume control. Along with Power and Mute, the input can be selected via teeny-tiny front panel buttons with BB-sized indicator lights or with the Arioso's unusual, palm-sized, paddle-shaped wood remote.


Listening: After a week of enjoyable listening with the Feliks, I needed to see how it would feel to swap in my long-favored, made-in-Japan Elekit TU-8600S ($1880 without tubes). I immediately noticed the TU-8600S's reach-out-and-hug-me fullness. The Elekit has a way of making sound sound embracing. Like the Feliks Arioso and the Parasound A 21+, the Elekit plays clear and bright and fast. It is not warm or soft, too wet or too dry, but it is supple and yielding, and—dare I say it—feminine. With the Elekit, vocal and instrumental tones are presented with a hormone-infused purity that sometimes takes my mind back to 1969 to Max Yasgur's farm 40 miles southwest of Woodstock, New York. Supervisual, supersensual audio on acid.

When I switched from the naked-at-Woodstock psychedelia of the Elekit TU-8600S to the Feliks Arioso—both amplifiers using Electro Harmonix Gold 300Bs—the amount of change that registered on my brain was no more than 20%. The most noticeable part of this change was the Feliks's distinctly higher degree of clarity, which expressed itself as a rather frank neutrality. The Feliks seemed clearer and more neutral than any amplifier I've used except the 25th Anniversary Decware Zen Triode and the Pass Labs INT-25.

When someone asks, "Herb, what do 300Bs sound like?" I answer, "Preternaturally clear!" I add, "With the right amp and speakers, they are the audio equivalent of 70mm movie film."

While powering the Falcon LS3/5a's, the Arioso did a super job at that hyperdetailed, wide-screen thing, but I was curious whether its midrange tone would become more saturated powering the DeVore Fidelity Orangutan O/93 speakers. The Falcons are 15 ohm speakers, and the DeVores are specified as a 10 ohm nominal impedance; therefore, I started out with both speakers hitched to the Arioso's 8-ohm taps (one pair at a time of course).


I hope it's okay to fall in love with classical music performers, because I've been doing it my whole life. My first crush was Kirsten Flagstad; my latest is another high-passion Norwegian: violinist Vilde Frang.

I have been repeat-playing Nelcor più non mi sento – introduction and variations on a theme from Paisiello's La molinara, Op.38, from Frang's and pianist Michail Lifits's 2019 release: Paganini & Schubert: Works for Violin & Piano (24/192 FLAC, Warner Classics/ Qobuz). Vilde's performance is locked in and emotionally intense. The violin sound is sharp, thick, and electrifying. I play this recording just to feel the density of sound from the violin. With the DeVores on the Arioso's 8 ohm tap, this recording felt quick and agile—but not as rich of timbre or as bitingly textured as I thought it should sound. (This deficiency was subtle, and it reflects my personal taste.) When I connected the 10 ohm DeVores to the Arioso's 4 ohm output tap, the sound displayed a more grain-free clarity. Colors became more saturated. The sound felt more correct.


I searched with Roon and found 1920s blues pioneer Henry Thomas's Texas Worried Blues: Complete Recorded Works 1927–1929 (16/44.1 FLAC, Yazoo/Tidal). I used the sound of his famous pan pipe as a guide for determining which output tap I should use.


On the 4 ohm tap, I played Thomas's "Bull Doze Blues," which, if you didn't know it, is the song Canned Heat's "Goin' Up the Country" is based on. As I listened, it became obvious: The highest notes from Henry's pan pipe were made to be played by 300Bs through speakers like these DeVores. With the Feliks amp, Henry's pipe notes appeared in vivid resolve with no excessive flare or glare. The 10 ohm speaker on the 4 ohm tap was now the happening concept. When I switched back to the 8 ohm tap, the sound became slightly more relaxed, a touch brighter, and spatially more diffuse.

Footnote 1: See Alex Halberstadt's recent review of the LM's successor, the LM-845IA, in the July issue of Stereophile.—Editor

Footnote 2: Feliks Audio, ul. Tuwima 2A, 42-700 Lubliniec, Poland. Web: US distributor: Upscale Audio, 1712 Corrigan Ct., La Verne CA 91750. Tel: (909) 931-9686. Web:


Ortofan's picture

... made by E.A.T.?

Herb Reichert's picture

but I am curious about E.A.T's 300Bs.