ATMA-SPHERE GEM INTEGRATED & “HEADPHONE AMP”- REVIEW
ATMA-SPHERE GEM INTEGRATED & “HEADPHONE AMP”
I had spoken with Ralph Karsten of Atma-Sphere, the world-renowned manufacturer of Output TransformerLess (OTL) amplifiers, several times on the phone. We are neighbors, and I had always been curious about the various Atma-Sphere products. The stories are many of individuals and couples discovering Ralph’s OTL amplifiers and keeping them till the end or near end-of-life, when they would be bequeathed to family or finally sold to someone else for their decades-long enjoyment.
During our various conversations, I slowly got to know Ralph and his knowledge of and love for his products, the technology that embodied his OTL amplifiers, and technology in general. I also learned a thing or two about the vinyl playback chain—cartridge, tonearm, phono preamplifier, etc.—and how those clicks and pops during playback that most of us were familiar with were for the large part not what we thought them to be. They were something entirely different and far more interesting. More on this to come.
It was during one of these conversations that Ralph spoke about a new and different integrated amplifier—the GEM. The GEM is a five-watt, push/pull integrated that uses EL95s as its power tube, fits on an 8-1/2 x 11 inch sheet of paper with room to spare, and can be carried on the palm of one’s hand. This represents a marked departure from the current stable of Atma-Sphere amplifiers. My curiosity was piqued all the more when Ralph mentioned that the GEM would also be a headphone amplifier. However, space considerations ultimately put the kibosh—the end—on the headphone segment.
I don’t know about you, but once I get something in my mind and it can be made so, I go about making it so. I had just reviewed the HIFIMAN Susvara, an exceptional headphone, however with a daunting sensitivity of 83dB that requires both qualitative and quantitative power—good power and lots of it! Based on our discussion, I thought the GEM would make for a good pairing, or at the very least, a worthy experiment. There was one very important thing, however, that I needed—an adapter—to transform the integrated into a headphone amplifier.
Well, I needn’t have looked farther than HIFIMAN and its very own adapter. It was built specifically to facilitate more power, via the conscription of integrated amplifiers as headphone amplifiers for some of its less sensitive headphones. The experiment was on.
A final point that Ralph made was that the Atma-Sphere GEM integrated is more than a match for an SET integrated of similar wattage, which he sees as a true apples-to-apples comparison. This, relative to an SET compared to a higher powered push-pull amplifier, which he does not believe is an apples-to-apples comparison. This experiment will be borne out in an up coming review—Part II.
REFRAIN: Unlike most reviews, this review will be non-sequential, as it will start with how the component actually sounds and not the process of physically “undressing” it and/or laying out its various parts, specifications, etc. Think of this review, then, as a non-linear movie—Memento, Kill Bill, Arrival, Eternal Sunshine of the Spotless Mind, etc.—that likewise starts at the end and winds its way to the beginning.
THE SYSTEM
The System - Headphone Reference
Grimm Audio MU1 Streamer
Silent Angel Rhein Z1 Streamer
Silent Angel Forester F2 Power Supply
Silent Angel Bonn NX Network Switch
Silent Angel Genesis GX Master Clock
Bricasti Design M1SE DAC
Aurorasound HEADA Headphone Amplifier
Atma-Sphere GEM Headphone Amplifier
Pass Labs HPA-1 Headphone Amplifier
ABYSS AB1266 PHI TC Headphone
HIFIMAN SUSVARA Headphone
MEZE Empyrean Headphone
Audience Front Row Cables/Wires
Kubala Sosna Emotion/Sensation—Cabling and Wires/Power Cords
RSX Beyond Power Cables
AntiCables Power Cables
Black Cat TRØN Signature Digital Cable
Audience Hidden Treasure CAT7 Ethernet cables
TORUS RM20—Power Generation
THE SOUND
Transforming the GEM into a headphone amplifier (HPA) was easily handled by the HIFIMAN Adapter ($99), a lightweight, simple, fit-in-the-palm-of-your-hand component. I cannot recommend the HIFIMAN Adapter highly enough for its plug and play functionality and its ability to render one’s integrated amplifier immediately into an HPA.
The sound of the Atma-Sphere GEM relative to the Aurorasound HEADA, our current reference HPA, is eminently more transparent and resolving of a given performance, which together fashion a greater and more profound sense of realism. It is a realism that translates to the intimacy of a violinist’s breathing, her movement with bow and violin, which becomes a great deal more intimate and immersive. You are pulled deeply into the performance, beyond just the music, as if the violinist is proximate, corporeal, in-room. Further, the GEM is more extended at both ends of the frequency spectrum, which results in a more impactful, tighter bass and a pristine, soaring treble.
There is an aliveness or liveliness to the music presented via the GEM that all headphone amplifiers reviewed to date, with the exception of the very top electrostatic headphone amplifiers, simply have not been able to match. And when this aliveness is matched to the GEM’s crystal clarity—the marriage of exceptional transparency, resolution, and detail— lightening fast transients, and stop-and-start-on-a-dime dynamics, well, the purview of a good number of headphone amplifiers has been surpassed. Did I mention the GEM’s fastidious way with the excavation of copious amounts of detail and its ability to lay bare detail that other HPAs cannot see?
The GEM’s frequency response from top to bottom plumbed the depths to the Holy-Bass-Head-Grail, while at the other end of the spectrum it soared easily and unhindered. Linearity? If a bass rich stream was fed through to the GEM, it rendered that bass rich stream impeccably. Likewise, should a given track, song, stream reach skyward, the GEM was right there with nary a harsh or sibilance-laced or brittle rejoinder; there was always just the music, pristine, beautiful, extended.
And I must say that as a reviewer’s tool, the GEM is exceptional. It demonstrates a non-invasive neutrality that allowed me to easily and quickly discern component and even cable switch-outs immediately.
Let me explain. “Neutral” is itself a horse of as many different colors as their are technical implementations to achieve it. This is something that I have experienced over many years. There is “warm-neutral” to, well, “soul-sucking neutral” that literally takes the life out of the music. This was not what the GEM offered up—it got out of the way! I could ascertain the differences between cables and components switched in/out in seconds. No long drawn-out A-B, B-A analysis, just take cable A out, put Cable B in, done. In this respect, the Atma-Sphere GEM is a reviewer’s dream. How many components allow this kind of immediate insight, while not “disabling” any aspect of the music? Very few.
The Atma-Sphere GEM’s volumetric cube encompassed the Aurorasound HEADA’s soundstage. And as I continued to listen, the GEM’s soundstage grew to match, if not exceed, even that of the ALLNIC HPA 10000. The GEM’s soundstage easily becomes what it must be—intimate, hall-sized, etc. And within the stage, volume, space, and air—dimensionality—are captured beautifully, with an exacting portrayal of musicians and performers positioned across the space and to its depth.
[Note: As I set up for the review, I stream the Getz/Gilberto 1964 masterwork (Verve Reissues) featuring Astrud Gilberto via the Atma-Sphere GEM and accompanying system (see System). Its rendering is crystal clear, see-through, rich, textured, phenomenal, as the signal passes freely and unedited to the Susvara headphones. It is perhaps the best rendering of this album that I have yet heard through headphones.]
Bass
The GEM unveils a deep and resounding bass response which the current reference simply cannot match. I have only ever heard the incredibly tight, deep, transparent, and detailed bass that the GEM now renders in the two-channel reference system and, if I remember correctly, with the Enleum AMP-23R integrated/headphone amplifier. Suffice to say that Charlie Hayden and John Taylor’s “Chairman Mao” (Nightfall, Naim Records) gives up hitherto unheard(!) information, while greatly raising the level of involvement. The track is now more see-through and full of life than it has ever been. And Delfeayo Marsalis’ “The Secret Love Affair” (The Last Southern Gentleman, Troubadour Records) is also more alive and propulsive, agile, and beautifully transparent. The overall result is that the bass response via the HIFIMAN Susvara is the best that it has ever been.
Did I mention the top-to-bottom frequency extension, which most five-watt SETs would beg, borrow, and/or steal to have? However, the thought that came continuously to mind was that the Atma-Sphere GEM was performing these feats with an 83dB “sensitive” headphone. Though I’m getting ahead of myself, as this is the bass section. The terms alive and liveliness do continue to come to my mind and to my notes across the entirety of the frequency range.
Midrange
The string of words that help to bring definition to the GEM’s performance across the midrange are, again, clarity, resolution, refinement, texture, and palpability. Joan Shelley’s “Wild Indifference” (Joan Shelley, No Quarter) is SET clear and textured, emotive and palpable as, perhaps would be rendered by a combination of 211 and 300B tubes. And it is as deeply resolving, transparent, and detailed as the most astute push-pull amplifier (tubed, solid state).
I have used Ólafur Arnalds’ “Àrbakkinn” (Island Songs, Mercury KX) as an indicator of how transparent and detailed a particular component or wire/cable is. The best of the best resolve very early on—within the first few seconds—the interaction of Ólafur’s recording studio as it interacts quite freely with the external environment and its singing birds. On the best components/wires the birds are immediate, their earliest discovery within the mix, coming some four seconds after the song has begun. The Atma-Sphere GEM captures this interaction, amid poet Einar Georg Einarsson’s recitation earlier still, and there are now several birds. Of course, this is but one measure of the GEM’s abilities with regard to detail retrieval and transparency. But then, never has Einar’s voice been so, well, real, beautifully articulated, dimensional, alive.
Treble+
Dave Brubeck’s “Take Five” (Time Out, Columbia-Legacy) cues and plays and it too is revelatory, as all previous discretionary write-ups of the frequency response—bass, midrange—have been.That aliveness is once again undeniably present, as is the air and space around Joe Morello’s drum kit. The treble resolution and transparency of Joe’s various cymbals is a level up in comparison to the exceptional Aurorasound HEADA, which until now has held off all comers.
Can a component be defined as astute? Because it certainly seems that the GEM is, well, more astute at communicating the flow of information, the various cues, textural and otherwise, the technical bits embodied therein that bring the music to life. The experience provides a crystal clarity that one experiences when seated right in front of a musician. Case in point: Hilary Hahn’s “Partita for violin Solo No. 1 B Minor” (Rest, UME) rolls in, and please know that the HEADA and the ALLNIC HPA have both played this piece beautifully. The GEM, however, brings an increased sense of engagement and again, an aliveness and detail that are new. Further, the quiet the GEM affords is outstanding, and, no doubt serves as the fulcrum from which deep resolution and transparency rise, with SET-like corporeal reality. Bravo!
Design—Look and Feel
The Atma-Sphere GEM integrated amplifier is, well, a straightforward, utilitarian design, which Ralph tells me will come in a variety of colors much different than its other offerings. The GEM is definitely an “Old School” design that harkens back to a much earlier, straightforward age, free of the glitz and glamour and the associated price tag. I, for one, find that rather appealing.
It is a tube forward design, with three exposed tubes per side (1-12AT7, 2-EL95s). The GEM is small enough to sit upon a single 8-1/2 by 11 inch sheet of paper. It easily makes for a very friendly desktop integrated or headphone amplifier (w/adapter), that did not compromise my workspace.
FUNCTIONALITY
Like the Atma-Sphere GEM’s design, its functionality is very straightforward and very simple. You will most likely not need an instruction manual to ferret out its workings.
There are two toggle switches on the front facade. The switch on the far left selects between two input channels—channel one (up) and channel two (down). The switch on the far right selects between On (up) and Off (down). There is also a knob centered on the GEM’s front face that controls volume.
The GEM’s rear facade features, from left to right: two sets of single-ended inputs, two sets of speaker terminals (0, 4, 8 Ohms/per side) beside them, next a fuse, and beside it to the far right, an IEC socket.
Ralph also mentioned for those wishing to “tube roll”—change the various tubes out for new tubes—that while changing out the two 6DL5s or EL95s would make little difference in the GEM’s sound, changing out the single 12AT7 would bring about more substantive changes to the overall sound signature of the GEM. FYI.
The Atma-Sphere’s design is straightforward, clean, and its functionality easy and easily comprehended.
CONCLUSION
The little Integrated/HPA that could and did might well be the title for this review, as the Atma-Sphere GEM was exemplary with all material that was streamed its way. Further, as a “converted” HPA, it dealt beautifully with perhaps one of the most demanding and least efficient, yet superb headphones—the HIFIMAN Susvara (83dB)—that I have had the pleasure to listen with and review. The GEM’s five watts were more than up to the task. This, of course, is a very clear indicator that your headphones, regardless of what they are, will be beautifully handled by the GEM. Period.
The Atma-Sphere GEM’s talent encompasses a crystal clarity that many amplification components strive for but do not achieve, incredible transient speed and leading-edge attacks reminiscent of far more powerful push-pull designs. You may well shake your head at this revelation, as I have on a number of occasions during this review, and again, this was with an 83dB “efficient/sensitive” headphone.
As mentioned above, I cannot think of another HPA I have reviewed that is as talented or as capable as the Atma-Sphere GEM ($4,700), and that includes the exceptional Aurorasound HEADA ($2,999), a longtime reference. And in many ways, but certainly not all, the superb ALLNIC HPA 10000 ($15,000), which does still rise above the fray, but at more than three times the cost of the GEM, one imagines it should.
Given the Atma-Sphere GEM’s bona fides, it is an easy winner of our DIAMOND AWARD for technical brilliance in a most simplified form, and its clean, unobtrusive neutrality, which lets it get out of the way and lets the music flow.
Pros: Crystal clarity, aliveness, transparency, and resolution of the SET realm, power, dynamics, and transient speed of the realm of push-pull amplification, as bonded together and placed within a small, unassuming package that fits nicely on an 8-1/2 by 11 inch sheet of paper.
Cons: It is not feature-rich. Most aftermarket power cords will not fit in the space for the IEC, as the fuse is positioned too close.
The Specifications
Atma-Sphere GEM
Power Output: 5 watts
Gain: 20-25dB
Differential Inputs: 2 - Single-Ended RCA
Speaker Outputs: 0, 4, 8 Ohms/per side
Tube Compliment: 1 - 12AT7, 2 - 6DL5 (EL95s)/per side
Frequency Bandwidth: XXHz - 100kHz
The COMPANY
ATMA-SPHERE
The GEM Integrated and “Headphone Amp” w/Adapter (below): $4,700
www.atma-sphere.com
ralph@atma-sphere.com
Tel. : +1 651-690-2246
HIFIMAN
HIFIMANAdapter: $99
store.hifiman.com
customerservice@hifiman.com
Tel.: 1-201-443-4626