Gramophone Dreams #81: Feliks Envy headphone amplifier

I always say I can't find what I'm not looking for, which doesn't mean I always know what I'm looking for. And not knowing what I want is unsettling. Recently, I was reminded of the thoughts of French polymath-philosopher René Girard (1923–2015), who suggested that people are not actually motivated by specific things like lust or capital or power, as major philosophers have declared, but by subtle, disconcerting forces of existential desire for something outside ourselves, never actually knowing what that something is (footnote 1).

Girard explains how this not knowing drives history and invention. His main premise is that we feel desire but, not knowing what we desire, mimic the desires of others. These "others" we mimic constitute a third element, interrupting the lines of force between a person and the objects desired. This, according to Girard, makes desire, and by extension human evolution, a nebulous but powerful anthropological force engaged in forming human cultures.

In other words, you might like big speakers and fat speaker cables, but maybe only because people around you appear to like them. Same with cars and clothes and lovers.

Girard's ideas helped me understand why it took me decades to identify the audio-system sound I've long desired but couldn't describe. Finally, in my dotage, I've recognized this sound and decided to give it a name: electrostatic midrange.

I first noticed the electrostatic-midrange phenomenon during my torrid affair with the Koss ESP/950 electrostatic headphones. The toaster-like glow of the 950's hyperdetailed, reverie-inspiring midrange reminded me of seeing the Milky Way when the sky is arctic-region clear, the stars appearing to touch each other. This was my first desire-forming experience.

My second experience forming my desire for electrostatic midrange came with my first set of Quad ESL-57s, which I bought mimicking the taste of friends Michael Trei and David Chesky. On the advice of audio chieftain Harvey Rosenberg, I powered my 57s with a Futterman H3 OTL amplifier. This system showcased truth of tone and hypervivid dimensionality—but only when I sat in the sweet spot. I sold this combination after a few months because the Quad's restrained dynamic and one-person sweet spot did not suit my lifestyle. Nevertheless, that ESL-OTL combo became my prime reference for how a system's midrange should sound.

I don't like it when electrostatic transducers sound brittle and staticky, which many of them do, but when the static is gone and the organic tones and spider-web detail remain, electrostatics' stark vividness becomes spellbinding.

I am recognizing this now because lately I've been using vintage Stax SR-207 and SR-700 Omega electrostatic earspeakers as my daily-driver transducers, and because, for the umpteenth time, a listening room visitor said, "Herb, your system sounds like headphones." I took that as a compliment and wondered if I'd been unconsciously striving for precisely that.

I am not saying that only electrostatics can make a psychedelic midrange. Indeed, that type of sound is a constant with the components I applaud in this column. For example, the incredible, true-to-life midrange of RAAL's full-range SR1a ribbons could win all contests for superior verity. JPS Labs' Abyss AB-1266 planar magnetics educe a midrange of preternatural clarity. And then there's HiFiMan's HE-R10P closed-back wood-cupped planar magnetics, which might be the kissin' cousin of HiFiMan's maximum-resolution Susvara. The Meze Elite make the smoothest, most cinemagraphic midrange ever. And ZMF's closed-back, dynamic-driver Verité headphone sounds more Koss 950/Quad 57ish than any of the aforementioned planar magnetics.

Each of these headphones delivers a midrange to impress even the most seasoned and demanding listeners. Each has made me feel like Alice tripping in Wonderland or Dorothy exploring Oz.

My term "electrostatic midrange" describes a type of sound. I'll use a different phrase to describe the type of listening experience I aspire to: Call it the "Alice & Dorothy effect."

This is the type of sound and listening experience I encountered at CanJam NYC 2023 as I auditioned Feliks Audio's eye-catching Envy headphone amplifier. If a single-ended triode amp paired with the right transducers can't manufacture a toaster-glowing, Milky Way–detailed midrange, what can?

Feliks Envy
We are blessed to live in a time when audio-product diversity is at an all-time high. There's a bewildering tsunami of headphone amplifiers at all price and performance levels. Singling out the best ones to review is like choosing the best doughnuts at the Supermoon Bakehouse on Rivington Street (footnote 2): intense fun but stressful and impossible. All I can do is pick amps that look tasty, which is what I was doing when I asked to review the Feliks Envy at the last CanJam NYC. Those Supermoon pastries are not free, but who cares? Every bite forms a distinct, pleasurable memory—as every track I played did with the Envy powering the HiFiMan Susvara.

Introduced in 2022, the Feliks Envy (footnote 3) is a moderate-sized, single-ended headphone amp sporting TJ Full Music 300Bs and Psvane CV-181 (6SN7) twin-triode voltage-amplifier driver tubes. Output power is specified at 8W. It is a zero-feedback design with solid state rectification and "automatic bias" on the output tubes. The uniquely styled Envy is made in Poland and measures 13.7" × 13" × 7.3" and weighs, notably, 33 1/3 lb. The outside of the Envy's chassis appears to be sheathed in solid ¾"-thick wood. It has three analog inputs, one balanced (XLR) and two unbalanced (RCA), and two preamp-level outputs, one RCA and one XLR. The front panel features two headphone jacks, one of them balanced, an input-selector switch, a three-levels–selectable gain switch, and a big, sexy Volume control knob.

Inside, the Envy is point-to-point wired using single-crystal copper with a Teflon dielectric; the coupling capacitors are Jantzen Superior Z-Cap. The Envy's balanced input transformers are made by Lundahl in Sweden, while its output transformers are made by Edis Ogonowski in Poland. This is heirloom-quality construction.

The Standard Edition (in solid Oak) costs $7995 and includes Russia-manufactured Electro-Harmonix Gold 300B tubes (footnote 4), Psvane VA tubes, and "premium copper wiring." The Performance Edition costs $8795 and includes China-manufactured "Full Music 300Bs with nickel anodes, and UPOCC (single crystal copper) wiring." In Walnut, both versions cost $200 more.

The Susvara is legend
With its 83dB/mW sensitivity, HiFiMan's Susvara headphone needs plenty of voltage to produce sufficient volume—hence, high gain. And because its impedance is on the low side, at 62 ohms, it needs sufficient power to support that voltage.

Despite common usage, the terms "gain" and "volume" are not equivalent. Volume refers to an external phenomenon: sound pressure level. Gain is an internal, electrical phenomenon relating an amplifier's output voltage to its input voltage. The achievable volume depends not just on gain but on headphone sensitivity. To support the gain necessary to achieve sufficient volume into the headphone's load impedance, the amplifier needs sufficient power.

To accommodate difficult loads like the Susvara's, the Envy's power is rated at 8W, and a front-panel control knob allows gain selection in three steps: Lo, Med, Hi (footnote 5). When the Susvara was driven at the Envy's lowest gain setting (also a low-impedance setting), music sounded clipped, dull, dark, and distorted. Even with the volume knob set at 5 o'clock, the music was insufficiently loud. At the medium gain setting, the volume level was comfortable with the control at about 12 o'clock; the sound brightened up and got nice. At the Envy's highest gain setting, at the same volume, it's like someone threw a knife-switch and the stage lights went on. It made the famously hard-to-drive Susvara light up and sing, with great purity and feeling.

With most amps, the Susvara's character leans towards dark and serious, but the Envy at the highest gain setting erased that melancholia, substituting clear skies, sunshine, and flowers.

ZMF Verité
Among the several products I've been regarding as unassailable, the sleeper of the bunch is ZMF's $2499, 300 ohm, 99dB, Verité closed-back planar magnetic headphones. Imagine the purest, truest tones with F1 drive and Mississippi Fred–level rhythm keeping. With the Envy powering the Verité, beauty and boogie combined forces to make focused listening easy. Recordings I've thought were not quite right turned out to be extremely right when I listened with the Verité powered by the Envy's Full Music 300Bs.

I've worshipped at the altar of David Lindley, singer-songwriter and master of all stringed instruments. His 1981 debut album with his band El Rayo-X (Asylum LP 5E-524) is spectacular on black disc, but the digital streaming version (16/44.1 FLAC Electra Asylum/Qobuz) has never grabbed me; I never listened all the way through until I listened with the ZMF Verité–Feliks Envy combo. With that, "Mercury Blues" came all the way alive, and my feet weren't tapping the floor; they were pounding it. My head was bouncing, and I was cruising on down the road. Plus! I can't mention this album of full-tilt rhythms without a shout-out declaring Ian Wallace, once a member of King Crimson, the alpha dog of funky drummers. On "Mercury Blues," Wallace was so good and having so much fun, he made me laugh out loud in the middle of a song.

After parking my new Mercury, I entered a seaside tango bar, and there she was: the beautiful Argentinian chanteuse Susana Natividad Rinaldi, sounding like Edith Piaf and looking like a singer in a David Lynch film. The seductive tones of Rinaldi's voice forced me to adore her. The dense reverb that framed her voice and made the band's instruments vibrant did not fog the recording's transparency or soften its focus. The album that supplied that vision is called A Homero Manzi (16/44.1 FLAC RP Music/Qobuz), and I swear that every instrument and player in her small orchestra was delineated clearly enough to watch and follow what they were doing on the stage.

I drove ZMF's 300 ohm, 99dB-sensitive closed-backs from the Envy's middle gain setting with its volume control set at 12 o'clock; there was some audible hum, but it was well back in space and low enough in level to not interfere with normal music listening.

Footnote 1: See

Footnote 2: See

Footnote 3: Feliks Audio, ul. Klonowa 12, 42-700 Lubliniec, Poland. Web: US distributor: Upscale Audio, 1712 Corrigan Ct., La Verne, CA 91750. Tel: (909) 931-9686. Web:

Footnote 4: We're aware of and sympathetic to concerns about buying Russian-made goods during wartime. We feel, however, that audiophile consumers should know the facts and make their own well-informed purchasing decisions. The facts are these: Electro-Harmonix tubes are made in a US-owned factory in Russia. Fortunately, for 300Bs (in contrast to some other tube types), there are excellent alternatives to Russian-made tubes, including the Chinese "Full Music" tubes and the US-made Western Electrics.—Jim Austin

Footnote 5: Until very recently, this knob was labeled "Impedance," and the Feliks website listed impedance specifications—not gain. Feliks recently decided to change the label to "Gain" without changing any of the circuitry.—Jim Austin


DaveinSM's picture

I must say, though I’m not in the market for one of these, this is a well written article.

In fact, the general quality of writing in Stereophile is notably higher than most online content out there these days,

I don’t know if it’s a generational thing, but I’ve noticed that younger writers online tend to write colloquially and grossly overuse parentheses in their articles. In some cases it makes for an almost unreadable, choppy mess, as if they’re adding the “like” three times in each sentence. Some of these people are lead editors, too.

Biggest culprits are at hodinkee and gearpatrol. Car and Driver is still okay but sliding over to that direction.

I don’t know if these people are in a hurry and pressed for deadlines, but they would do well to have someone proof their stuff for flow and readability before throwing it up there.

Charles E Flynn's picture

Some of the articles that Gear Patrol has published about audio topics are cringemaking, but this one is worth a high-speed skim:

What Does “Hi-Fi” Even Mean Anymore? This Is What the Experts Say
at .

Note the lack of proofreading (bold style added):

Charlie Randall, co-CEO of the McIntosh Group
“When used to describe equipment, ‘hi-fi’ means to be able to reproduce recordings of all types CD, vinyl or streaming. To be considered hi-fi, the equipment must be capable of playback with very low distortion, low signal-to-noise ratio, dynamic headroom and channel separation just to name a few.

For an example of one of the best pieces at Gear Patrol:

8 Ways to Make Your Kitchen Knives Last Forever, According to an Expert

JohnnyThunder2.0's picture

have always been top notch - great magazine journalists. Mr. Holt started it all - he had an amazing way of describing what you hear and equipment and technology and etc. and still make it a very entertaining read. A great writer! As are or were, Sam, Art , Corey, John A, Martin, and now especially Herb, Jason, Kaleidoscope, Alex. Did I mention Herb?

Laphr's picture

The high end is in trouble if it doesn't carry on relating what it actually sounds like. Consumer-grade components are a mile from that sound. We're fortunate to have that list of writers, as well as Lavorgna and the rest. They remember and they practice the good stuff. I hope Stereophile management realizes that lesser rags and the peanut gallery are crap, and I hope that this site defends distinctly great sound.

kai's picture

Would have liked to see measurements on this one.
Those could come out much more interesting than with some solid state amps that measure beyond good and bad anyway.

The sound difference between the three gain stages e.g. could have a correlation with linear or harmonic distortions or output impedance, or simply different max. power.

Jeffrey L.'s picture

More than anything else here Herb, this is just a thank you for being a pleasure to read. You nailed it when you coined the phrase “electrostatic mid range phenomenon”

Been on the Quad merry go round for over 25 yrs,(bailed out due to ongoing repairs) the mid range, as you say is to die for, but to find that same presentation in something other than a panel ?,….difficult.
Until I read your words, “reminded me of electrostatics with dynamic range” , I thought, I have to check this out. Of course your review was about Zu Soul Supremes. Long story short , I tracked a pair down here in Oz. Have never been happier.
Thanks Herb, every thing you write/review now is going to be something I should pay close attention to.
Can’t afford them of course

MLP's picture

Make sure to subscribe to the magazine. Good journalism requires subscribers to pay the bills.