HiFiMAN HE-500 Headphones and EF5 Headphone Amplifier

by John Crossett | June 25, 2014


Synergy -- the interaction of elements that produces an effect greater than the sum of the individual parts -- is a word used freely in audiophile circles. True synergy comes from well-thought-out design with complete compatibility as a prime consideration. Everything has to be perfectly aligned to create real synergy. When I get two different components, such as the HiFiMAN EF5 headphone amplifier and HE-500 headphones, from the same company, it should be a safe assumption that true synergy will be both the guiding factor in their design and the reason they were sent together. Unfortunately, that isn’t always the case, so this HiFiMAN pairing certainly puts that theory to the test.

The EF5 is a relatively small tubed headphone amp, a two-piece affair that includes the DY-1 power supply and the one-meter umbilical that attaches it to the EF5. While the umbilical allows you to separate the two units physically if you feel that this delivers better sound, I tried it and didn’t hear any difference, so I used them one atop the other. The EF5 is technically a hybrid design, using a single 12AU7 tube in its input stage, while the DY-1 is compatible with either 110 or 220 volts, thereby ensuring it’ll work wherever you may be in the world. Smart. The EF5’s output stage uses an OPA275 op-amp, making it especially load-tolerant and able to drive whatever headphones you choose to use. With a frequency response from 20Hz to 30kHz, a signal-to-noise ratio of more than 95dB and THD of less than 0.2%, its specifications are excellent, and with an input impedance of 50k ohms and output impedance designed to drive headphones rated from 2 ohms to 2k ohms, it should be comfortable with pretty much anything out there. On the front of the EF5 you’ll find an on/off toggle switch, a 1/4" headphone jack, and a rotary volume knob. On the rear there’s a socket for connection to the DY-1, along with a pair of gold-plated RCA input jacks. Styling extends as far as an acrylic top plate for the EF5, allowing you to glimpse the inside, a hole to the rear accommodating the 12AU7 tube, guarded by a stack of small acrylic plates to prevent accidents. Both units measure 4 1/3"W x 2"H x 10 5/8"D, and together they weigh a little less than six pounds.

The HE-500 headphones are built around a planar driver -- a single very thin diaphragm that uses the same technology as Magnepan speakers, though on a far reduced scale. I asked Peter Hoagland of HiFiMAN’s US base why Fang Bian, HiFiMAN’s owner and designer, who resides in China, elected to go with a planar design. After the "he loves electrostatic headphones as the gold standard (of headphone sound)" answer I expected, Hoagland said that the expense of electrostatics and the difficulty of both manufacturing and driving them made Bain explore planars as a means of re-creating the sound he loved at a more affordable price.

The HE-500s have a sensitivity rating of 89dB, so any reasonable headphone amp should be able to drive them without issue, due in part to their sensible 38-ohm impedance. Weighing in at about 1.1 pounds, the HE-500s are not the lightest ‘phones I’ve worn, but with their padded leather earpads (they come with a velour set as well) they are certainly comfortable enough.

One feature of the HE-500s that really caught my attention was the three-meter silver cable fitted with connectors, one for each side, that screw into jacks at the base of each earpiece. I’m a big fan of silver cables used with headphone gear as, in my experience, silver seems to provide better conductivity and improved transfer of the delicate signal. One thing to note, however, is that the cable, excellent as it is, will make noise when it contacts anything hard -- like zippers on clothing or even itself. Not a deal breaker, but just something you need to be aware of so that you won’t have your listening marred by external noise.

I’m a huge admirer of planar drivers, whether they be used in speakers -- I’m a Magnepan fan from way back -- or headphones (see my review of the Audeze LCD-2s from December 2010). I am also a big fan of tubes, for all of the standard reasons, including that they simply sound more musical that solid state. So the EF5/HE-500 combination set out with something of a head start. But I’m realistic enough to know that just because something uses parts or an approach that I find appealing, it doesn’t always translate into a product I’ll enjoy listening to. I’ve had my assumptive balloons burst just often enough in the past to keep me wary.

So imagine my pleasure when I found that although the HE-500s don’t sound the same as other planar designs I’d heard, they were still thoroughly enjoyable, while the EF5, despite its small size and low cost seemed purpose-built to maximize fun when paired with these ‘phones. "Enjoyment first and foremost" could almost be HiFiMAN’s tagline.

The first recording I played was the title cut from Andy McCloud’s CD Blue’s For Bighead [Mapleshade CD 07832], and as soon as the initial notes popped into my head, I discovered how thoroughly musical the HiFiMAN pairing was. It was like listening to some of my favorite pieces of classic audio equipment, products that allow me to simply relax into the music. The HiFiMAN combo doesn’t suffer from the sepia colorations of those past audio favorites, but it still gave me that same relaxed enjoyment. McCloud’s bass was warm and deep, with each note being both richly imbued with tonal color and extremely well defined. The sense of his fingers plucking each string was unmistakable. Alto saxophonist Joe Ford’s instrument had just the proper reedy bite to give it a feeling of realness. But the standout instrument here was Steve Nelson’s vibes. The sound of his mallets hitting the metal bars and the shimmer of each note were something of a revelation. Crisp and sharp, with transients that wafted off into the recording's ample space, they were reproduced as if I was sitting right next to Pierre Sprey as the music was recorded.

This combination’s way with bass was underlined by listening to Marcus Miller’s CD M2 [Telarc CD-83534]. Miller plays electric bass here, and the differences in sound between his bass and the acoustic one used by McCloud were unmistakable. Miller displayed a powerful purr, which nearly screamed "electric instrument," while McCloud's plucked notes were better defined. With Miller the sense of a big acoustic instrument was missing -- as it should be -- replaced by the signature of the amp Miller used. I found the level of detail down into the lowest registers to be outstanding, even more so given that neither planar drivers nor tubes have ever been noted for their ability to reproduce bass with such accuracy and depth.

The EF5/HE-500 combo’s sound definitely leaned more toward the lower frequencies, giving the presentation greater force and weight. If you yearn for crisp, clean highs, this might not be the combination for you. I’m not saying the top end was muted or reined in. As if to prove just how well the EF5/HE-500 setup handled treble, I pulled Holly Cole’s self-titled CD [Alert 6152810418]. The piano was vivid and the hammers striking the strings and creating the notes -- all of them -- was totally realistic, each note expanding into the recording’s space with a realness that, for a quick second, had me opening my eyes to see if I was still in my listening room.

The Holly Cole album also showed off the HiFiMAN combo’s way with the human voice. Listening through the EF5/HE-500 duo, I don’t know that I’ve ever heard Cole’s voice reproduced with such stunning reality. This is a superb recording, and the pair let me hear how good it is by offering a very real sense of air flowing from her diaphragm up past her vocal cords and out of her mouth. It seemed as though I could almost see her mouth forming each word. The HiFiMAN duo didn’t just handle lead vocals well. It was just as impressive with background vocals and voices buried deep in the mix, such as Stanley Clarke on his album Standards [Kind Of Blue 10010] and the Thelonious Monk tune "I Mean You." It’s easy to hear that Clarke is softly singing along with a tune he loves, but with the HiFiMAN combo it is equally clear just what he’s singing as well, so clearly does it reproduce the myriad little things that help make listening to music a pleasure.

Orchestral music really shone. Tubes, planar drivers, and acoustic instruments are a match made in audio heaven, and the HiFiMAN setup demonstrated why. I pulled the SACD of Prokofiev’s Alexander Nevsky [Mobile Fidelity/Vox UDSACD 4009] from my music rack and sat back to revel in a piece of music that has always thrilled me. It was as though I’d stepped back to 1979 and was in the presence of the St. Louis Symphony under the baton of Leonard Slatkin. The strings had both the silky sheen and rosin-infused bite of the real thing. The horns were reproduced with the requisite blat. The reeds had the sound of air being blown past them and into the bodies of the instruments. And the cellos and basses were both deep and clear while laying the proper foundation for the piece. Dynamics, as the score went from soft to loud, were wonderfully convincing, the music swelling then receding. Plus, and this is a neat trick for headphones, there was a real sense of a soundstage laid out, almost to the point of feeling like it stretched beyond the headphones themselves.

The Nevsky was one of the discs that brought out EF5/HE-500’s way with acoustic instruments. Another was a recently received sampler SACD called Showcase 2013 [Opus 3 CD 23000] drawn from Opus 3’s extensive recording catalog. The self-titled track by the group Sticks & Stones was one tune that drove home just how well this headphone and its matching amp synergized into a whole that transcended the sum of the parts. Sticks & Stones use both acoustic guitar and mandolin and the HiFiMAN pairing not only reproduced each with the correct tonality, but also gave an honest impression of the relative size of these two instruments. Listening to strings plucked on each was incredibly illuminating; just by tone alone I could hear the cavity of each instrument, reflected in the depth and richness of each note. This disc also helped reinforce the manner in which these two products, working together, made voices as diverse as the bluesy B.B. Driftwood and the gospel-tinged folk sound of Eric Bibb, the light and airy sounds of Rebecka Sjoberg and the sophistication of jazz singer Maria Winther, sound unique to each singer.

Finally, the HiFiMAN pairing didn’t seem to have any discernible dynamic limits. Listening to Duke Ellington’s band on the SACD Blues In Orbit [Mobile Fidelity/Columbia UDCD 757] brought this home in spades. A jazz band in full cry can (and should) be an impressive sound. Part of Ellington’s genius was playing the thunder of the full band against the delicacy of the individual musicians. The EF5 seemed to have all the power necessary to produce that thunder, but also the subtlety to reproduce the individual instruments. This is where the HE-500’s planar design really shone brightest. The lightness of the diaphragms made it seem as though the drivers could start and stop on a dime while still being able to rumble when called upon to do so.

There was no sense of compression to identify the fact that I was listening to a recording, or limitations in the mechanics of its reproduction. For example, "Blues In Blueprint" begins with just Harry Carney playing his baritone sax in duo with Jimmy Webb on acoustic bass. The saxophone was full and reedy, the acoustic bass deep and wooden. Slowly Ellington brings in the balance of the band. As more instruments become involved and the tempo of the music rises, the EF5/HE-500 pair never skipped a beat, handling the increase in musical density and level with aplomb.

After having spent considerable time with the EF5 and HE-500 together, it was time to separate the two and see how each fared on its own. I began with the HE-500s connected to my Master Electronics Original headphone amp ($200), as well as my HeadRoom Portable Micro with DAC ($549) just to see how these planar cans would run on portable power.

The Master Electronics is similar to the EF5 in that it is a two-box unit, using an external power to keep any unwanted noise far from the delicate audio signal. It is also a solid-state design, and perhaps for this reason I heard deeper, more detailed bass. That is exactly what I expected. What I didn’t expect was that despite the extra depth offered by the Master, I lost some of that sense of realism that the EF5 delivered so effortlessly. I was pleased to note that the HE-500s were resolving enough to sort out this kind of difference. Moving to the treble, I found that the Master had a more extended top end, which showed that the HE-500s actually have a top-to-bottom frequency response that is right up there with any headphones I’ve heard. When I played the DVD-A of Mike Oldfield’s Tubular Bells 2003 [Warner Brothers DVD-A R9 60204], the shimmer and slam of those tubular bells was reproduced with sparkle that just kept going, well beyond the limits of my hearing.

But what truly impressed me about the HE-500s was how good they sounded used with my little HeadRoom unit. Using my Apple iPod Classic full of Apple Lossless files as source, the combo reproduced some of the best "personal" sound I’ve heard -- hands down. Everything I’ve described above was just as evident with this setup. The HE-500s really are a top-notch set of headphones, fully at home however I chose to use them.

Switching the focus to the EF5, I used my own reference headphones, the AKG K701s ($499), to assess it in isolation. What I heard was a quick, agile, and detailed sound. Thanks to that tube output, there was no lack of body to either instruments or singers. And this combination had the ability to dig deeply into the music and extract minute details. One of my favorite SACDs is The Paperboys -- Live in Stockfisch Studios [Stockfisch SFR 357.4054.2]. One of the reasons I love it, right up there with all the wonderful songs, is the abundance and sheer range of acoustic instruments -- everything from acoustic guitar to banjo, fiddles to flutes, whistles to acoustic bass and drums. The EF5 reproduced them all, each with a real sense of body and shape; the guitars had the sound of strings over a large wooden body, while the banjo’s sound was unmistakably that of strings exciting the skin of the body cover. Finally, both the male and female vocals were distinct, easily identifiable entities. What the AKGs showed me (the '701s are renowned for their top end) was that the treble wasn’t quite as extended as I’d heard from solid-state designs. But with the magic the EF5 makes in the midrange, this was a non-issue for me. Your ears may hear things differently, of course.

Taken together, the HiFiMAN EF5 headphone amplifier and HE-500 planar headphones displayed what real synergy is all about. While each piece is wonderful on its own, brought together they shine brighter than one has any right to expect, especially given their modest cost. In one sense they won’t wow you right out of the gate, simply because they sound so balanced and natural -- as opposed to hi-fi spectacular. But this is an insidious pairing, sounding so complete that the longer you listen the more you’ll find yourself getting lost in the musical performance, as opposed to the hi-fi performance of the equipment. They just get the music -- and so will you. Every time I fired up this pairing was akin to slipping on my favorite pair of jeans -- it just made me feel relaxed, comfortable and right. From jazz to classical to rock to whatever else I played, the HiFiMAN duo took the "It’s doing this or that" reviewer-think right out of the equation. Instead they allowed -- almost forced -- me to relax and enjoy my time with my favorite music -- and I can’t give higher praise than that. Given their more than affordable price, I consider that this pairing could very well be the go-to choice for a personal listening system for those who can’t shell out big bucks for a headphone setup.

Real synergy -- listen to these two together and you’ll understand.

Prices: HE-500, $699; EF5, $499.
Warranty: One year parts and labor.

HiFiMAN Electronics Corp.
711 Dawson Drive
Newark, DE 19713
(201) 443-4626

Associated Equipment

Digital: Oppo DV-981HD universal player, iPod Classic 160GB.

Headphones: AKG K-701.

Headphone amps: Original Electronics Master, HeadRoom Portable Micro with DAC.

Interconnects: Analysis Plus Solo Crystal Oval.

Power conditioner: Blue Circle BC6000.

Power cords: Harmonic Technologies Pro AC-11, Analysis Plus Power Oval 10.

Second take

It's difficult to pass by the HiFiMAN booth at any audio show and not admire the company's gleaming products and expanding product line, which includes a half-dozen different headphones and amplifiers. Both the HE-500 'phones and the EF5 amp are near the top of the company's offerings, but they're reasonably priced when you consider that you're getting a healthy dose of the esoteric with your personal-listening rig: planar drivers in the headphones, tubes and a separate power supply with the amp. These are both well-made products, crisp in appearance and thoughtfully executed.

Used together, the HE-500 and EF5 underscore what makes personal listening so compelling for audiophiles (not to mention hardcore personal listeners). They achieve a few things that many -- even most -- amplifier-loudspeaker combinations would be hard-pressed to equal at any price, let alone $1200.

First and foremost are the honesty and directness of the midrange, the proverbial clean window on the fat part of the musical signal. Vocals are vivid and unfettered, like from speakers with no crossover point remotely close to the middle frequencies. The high frequencies capture the subtle sheen of brushed cymbals as easily as the roaring overtones of electric guitar. The air and ambience of the recording venue are well rendered, giving the presentation a sense of existing beyond the listener's head. The bass is not as potent as with some other headphone-amp combinations, especially those that include one of the upper-end Sennheiser 'phones, whose balance has always struck me as being more like that of a pair of audiophile speakers, right down to the depth and power of their bass.

I also listened to the HE-500 headphones with my reference amp, a solid-state preamp/headphone amp that Angel Despotov of Analog Domain made and sent to me, and it made for an interesting contrast. The EF5 sounds more demure and slightly softer, taking a bit of the edge off transients. However, the mids are more lush and colorful with the HiFiMAN amp, sort of like the image a very good plasma TV produces compared to that of the newest LCDs.

Finally, the HE-500s are incredibly comfortable for a robust over-the-ear design. Headphone comfort is highly subjective, the shape of our heads and ears being anything but a constant. But the plush earcups and lighter weight mean that the HE-500s will have a better chance of fitting a wide range of listeners than some highly touted but bulky 'phones, like those from Audeze, for instance.

All in all, this is a refined pairing, although I do think the HE-500s have an even higher performance ceiling based on what I heard from them with a different amp. However, if you don't want to hunt and peck for a pair of 'phones and an amp, the HE-500s and EF5 are a fundamentally enjoyable combination, which is a point that John Crossett also makes. This isn't exactly a top-of-the-marquee compliment, but it does describe what this amp and pair of headphones are about.

-Marc Mickelson