I spend my days comparing cartridges and speaker stands, arguing about imaging and microphone placement, speculating about DAC filters, and lately, sometimes, very secretly listening to headphones connected not to commercially available headphone amplifiers but directly to the outputs of basic tubed and solid-state power amplifiers. No person in his right mind would or should try thisit's too easy to destroy a pair of delicate, expensive headphones. But for me, it's been worth the risk.

My unauthorized experiments have been revelatory, and I have learned two things: 1) The sounds of today's best headphones are considerably more nuanced, weighty, transparent, and microscopically descriptive than I ever imagined. For me, this makes it obvious that 2) All of the regular headphone amplifiers I knew of were masking, blurring, and obscuring recorded information.

Right from my first hand-trembling experiment, as I turned up the preamp volume, hoping to hear not exploding diaphragms but nice music, I experienced a surreal Twilight Zone of enhanced three-dimensionality, ear-opening clarity, and hypertactile corporeality.

The more I experimented, and the more I heard such uncanny unveilings, the more I realized that the cause of this newly discovered verity would not be so easy to determine. But it seemed to me that my headphones liked power amps with high-voltage power supplies that can exhale current into reluctant drivers. It seemed that the best unveilers might be amplifiers that use little or no feedback, while amplifiers with low parts counts and those parts of very high quality might sound the most vivid.

Best of all, I was able to experience what a great headphone amplifier could and should sound likeespecially when driving less-sensitive headphones like my reference JPS Labs Abyss AB-1266 Phi's ($4595, 88dB/mW), and HiFiMan's new Susvaras ($6000, 83dB/mW). The Susvaras are reviewed below.

Do not try these experiments at home

But if you feel compelled to experience what I've just described, connect your best headphones to Rogue Audio's robust RH-5 preampheadphone amp, which I reviewed in the November 2017 issue of Stereophile; that will get you most of it. Or, better still, try HiFiMan's superpowered EF1000 headphone amplifier, also reviewed below. It's a basic tube-and-solid-state power amplifier that also happens to be perfectly appropriate for use with headphones. That will get you all of it.

HiFiMan Susvara planar-magnetic headphones

The latest creation of Dr. Fang Bian, founder and chief engineer of HiFiMan, is the new Susvara headphones ($6000). These are "full-size," over-ear headphones with planar-magnetic drive-units, and they cost almost precisely twice as much as HiFiMan's HE1000 V2 headphones ($2999), which I reviewed in my April 2017 column. While similar in looks, the Susvaras' earcups are round, not oval like the HE1000 V2s'. Their fit and finish seem more finely wrought, and they felt cozier on my head than the HE1000s. Both are elegantly styled in that unique HiFiMan way.

When I opened the Susvaras' box, all I could see was the owner's manuala sumptuous hardbound book with a slick, satin-finish dustjacket and thick, glossy pages. On cover and jacket, "SUSVARA" is printed in gold in a delicate font. The thin gold letters hint at Fang Bian's latest invention: his thinner-than-ever, Nanometer Grade Diaphragm, coated with gold.

According to the manual, "when sound waves generated by the diaphragm pass through the magnet, there is interference that degrades sonic purity." The Susvaras' new Stealth Magnet endeavors to correct this. Instead of having right-angle edges on all their exposed surfaces, the individual strip magnets that comprise each driver's magnet grid have rounded edges on their surfaces that face away from the diaphragm. This convexity supposedly lets waves of pressurized airsoundwavespass through the grid relatively unmolested, thus preserving the waveform integrity of the diaphragm's output. To further preserve this integrity, the Window Shade grilles on the earcups' outer surfaces have been "painstakingly optimized to avoid any resonant frequencies."

I doubt that the gold on the Susvaras' diaphragms is the cause, but though they're smaller than the HE1000 V2s, the Susvaras, at 15.9oz, weigh 1.1oz more. And speaking of more, the Susvaras present an amp with a nominal impedance of 60 ohmsalmost double the HE1000's 32 ohms. The most noticeable difference between these premier stablemates is their sensitivity: a low 90dB/mW for HE1000 V2s, while the Susvaras are really low at 83dB/mW.

The Susvaras' cable comprises a "single crystalline copper wire alongside a single crystalline silver wire." Super-supple, it never twisted or knotted up. It's the most elegant, durable, user-friendly headphone cable I've ever used.

With the Pass Labs HPA-1: The Pass Labs HPA-1 ($3500) is a reference-quality preamp and headphone amplifier that first revealed to me the ultratransparency of HiFiMan's HE1000 V2 headphones. The HPA-1 and HE1000s manifested an extremely refined and superbly musical presentation. Now, with the Susvaras, that same HPA-1 gave me all the effortless flow, natural detail, and spatial descriptiveness that Fang Bian's new headphones are capable of. Unfortunately, I did most of my listening to highly dynamic, uncompressed recordings played at moderate volumes. For this, the HPA-1's volume control had to be set between three and six o'clock. Due to the combination of the HPA-1's 8dB gain and the Susvaras' low sensitivity, listening at higher volume levels was not possible.

With Mytek HiFi's Manhattan II: Voltage gain is not a limitation of Mytek HiFi's Manhattan II DAC and headphone amp ($5995). In fact, if you're not careful, it can produce too much gain. But, luckily for the Susvaras, a front-panel menu lets the Manhattan II's user select among eight voltage-gain settings. This feature let me enjoy music via Tidal streaming while precisely adjusting the Manhattan's Volume Trim until I liked the way the music sounded (dynamically), and the volume control operated in a good place.

Through the HiFiMan Susvaras connected to the Manhattan II in balanced mode and with the Mytek's Volume Trim set to maximum gain, "Come Over," from Morphine's At Your Service (CD, Ryko/Rhino RH2 520603), was beyond impressive: strong, completely open, and fully expressive. Mark Sandman's lines on two-string electric bass were psychedelic, tight, and just begged to be followed. There was plenty of punch and bite, no mud or hesitation. Following Sandman's twisting bass notes and pithy vocals is extremely importantcombined, they're the soul and the poetic content of these Morphine outtakes. In "It's Not Like That Anymore," the drums seemed pitch-perfect and properly scaled. The baritone saxophone was just above me on stage, clear, foghorn rich, and achingly plaintive.

The Mytek Manhattan II DAC-amp showed me how transparent, liquid, and resolving the Susvaras could be.

With the Rogue Audio RH-5: I don't see how anyone can fully evaluate headphones while listening only to over-compressed pop, rock, or hip-hop. Of course, such recordings will reveal plenty about the quantity of bass, basic midrange character, and high-frequency tolerability of entry-level headphonesand that might be all you need to know. But at $6000, HiFiMan's Susvaras are the opposite of entry-level 'phones, and demand more sophisticated musical program and an amplifier capable of unraveling complex recorded events.

With the exception of the HiFiMan EF1000 ($15,000), discussed below, the Rogue RH-5 ($2495) is currently the best amp I have for driving the Susvaras. It has the gain, the raw power, and the wide-open tube liquidity the Susvaras require to achieve the full force and flower-like beauty of their sound.

For some sophisticated music, I chose J.S. Bach's Orgelbüchlein (Little Organ Book), in an arrangement for chamber ensemble performed by the Ensemble Mare Nostrum under the direction of Andrea De Carlo (CD, MA Recordings M076A). Imagine several bass and tenor viols, a portative organ, an archlute, a boy soprano, and the enchanting soprano of Celine Scheen. Imagine, next, how breath-releasingly, stress-removingly natural the Rogue and Susvaras could possibly make this organ tutorial sound. Imagine a precisely drawn spatial perspective. Imagine all that is joyful in Bach unfolding in an easy, quiet flow, with copious luster and organic textures. That's what I experienced. The Susvaras were better than any other headphones I know at delivering music at low volumes with acuity and scintillating dynamics.