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As headphone amp: Unlike most such arrangements when a headphone slips into a ¼" jack, the LS100 does not mute its main outputs. This eliminates potentially sound-degrading auto-mute circuitry. It also means you'll have to power down your speaker amp. Easy. How much 'power' the LS100 can parlay into various headphones depends on the output voltage of your source—from a docked iPod's 1V to a CD/DAC's industry-standard 2V to non-standard outputs like my 5.45V max Weiss DAC2 and 10V max Burson HA160D—plus headphone impedance and sensitivity. The higher the headphone impedance the less efficient the power transfer. Just how far one has to turn up the volume for any given headfi load additionally depends on the taper of the pot.


The 50Ω HifiMan HE-6 planarmagnetic/orthodynamic is currently one of the most power-hungry such loads available. With a standard 2V source it'll fully max out the LS100 to 5:30 on the dial. Most could find those SPL sufficient on most music. Some might want more. Call it borderline. But a rough doubling-plus of source voltage will already afford ear-bleeding levels as the equivalent setting to 2V now becomes 2:30. This builds in sufficient headroom.


With a 2V source, Audio-Technica's efficient W-5000 'Raffinato' achieves the same levels at 11:00. The Audez'e LCD-2 and Sennheiser HD-800 get there at 1:00. beyerdynamic's T1 and AKG's K-702 take until 3:00. Whilst loudness is a personal matter it seems fair to say that HifiMan HE-5LE/6 excepted, all current full-size headphones should be copasetic with the ModWright from standard digital sources. Once source output voltage doubles to 4V or beyond, even the most hard-of-hearing orthos can turn head bangers to become unconditional. That makes the LS100 an essentially universal hybrid headphone driver where, per ear, half a 6SN7 triode for voltage gain combines with a FET current buffer and a power supply that would seem massively overbuilt for the occasion.


Given sheer size and price it's of course unlikely that anyone would acquire the ModWright just to power headphones. Its footprint is so over-dimensioned that I bolted three pointy metal footers into the provided bottom-plate threads (that's exactly how the matching KWA100 is delivered). Being set back farther from the edges than the four stock rubber footers, the resultant shallower footprint suited my 40.5cm deep ASI HeartSong rack better. The rubber footers overhung by half front and back. That was a bit precarious. Any stock footer setup will want a shelf at least 45cm deep.


With seven headphones and more than 10 headphone amps in my collection, this part of the assignment asked for selectivity to keep focused. I thus picked the Audez'e LCD-2 and Sennheiser HD-800 as opposing yin/yang flavors to represent true top echelon headphones. For amps I settled on three tubed competitors: the Trafomatic Audio Experience Head One with 6S45Ps rectified by an EZ80; the mighty Woo Audio Model 5 with two 5U4G supplying 6SN7-driven 300Bs [all glass by Create Audio/Synergy Hifi]; and Schiit's new high-output hybrid 6922/Mosfet Lyr.

Trafomatic Audio Experience Head One with ALO Audio recabled Sennheiser HD800 on Sieveking Sound Omega stand

The general verdict is that inherently lit-up speed-freaky lean-ish and emasculated earphones of uncorrected HD800 flavor—a proper after-market leash pays huge dividends on these—are predestined for the LS100. Its mellowing relaxing action and parallel fattening up are perfectly complementary and compensatory to the stock Senn archetype. While the 6SN7s are admittedly not the last word in top-end air, transient zing and ultimate detail, the HD800's extra helping of those ingredients more than makes up for it. Such pairings exploit the old fire 'n' ice tactic. One strategically splits the difference to arrive somewhere in the middle.


An inherently darker ultra-moist and rich presentation as one finds natively in the Audez'e might for some tastes veer too deep into density and opulence with the ModWright. Others could pursue that exact pairing for how it celebrates that flavor. Though musical flow decelerates a bit, dynamics (already a very strong suit of this push/pull flat-membrane device) receive an extra infusion. Nothing thus tips over into the portly/soggy polarity. Think 80% cocoa chocolate with a hint of cayenne - dark and rich yet not really sweet, well developed flavor complexity with real kick. This pairing would be a rather magnified polar opposite to running the Sennheisers with stock harness off Burson Audio's transistor HA160.

LS100 vs. Head One: Texturally and dimensionally, the Serbian was drier and smaller, the American fluffier and grander. The 6S45Ps made for a more focused and compact presentation. It had more top-end extension but applied more overall damping against the ModWright's more opulent dimensionality. This latter feature's distinctiveness—the degree of difference—was maximized by the planar headphone. It sounded noticeably larger and more voluptuous with the LS100. The HD800s didn't respond alike. Their innate airiness was underlined more with the Head One. Those elements usually grouped under the PRaT catch-all also firmed up more. The 6SN7s played it structurally looser. The upshot was that with the Audez'e the ModWright was the clear winner. With the Sennheisers meanwhile the amps were on the same plateau but the Serbian amp seemed to play a bit more to their particular personality strengths.
Schiit Lyr with stock JJ 6922

LS100 vs. Lyr: Here the Schiit with stock tubes stepped into the foot prints of the Serbian, then added bandwidth particularly on top, revved up subjective resolution magnification and further built out the theme of control/damping. Thus the flavor difference stretched out. It became more overtly about dark/lush/relaxed vs lit-up/energetic/driven. Those attracted to the Sennheiser for its obvious virtues would find the Lyr to maximize them, the LS100 to deliberately mellow them out (which in this context equates to downplaying and diluting).


With the Audez'e the primary difference was the wholesale injection of air and illumination from the midrange on up. While acting as mostly equals on low-down grip and manly fortitude, the Lyr added a fresher more piquant flavor higher up. Many should find this livelier and certainly more informative. The flip side is a higher degree of sharpness and glassiness on usual overcooked Pop productions. High-noon lighting with its lesser shadows and starker contrasts makes for very crisp visibility. There warts & Co are exposed more mercilessly. On raw resolution in the range where human hearing is most acute the Lyr was definitely victor. It was adrenaline to the LS100's comfort zone. In this juxtaposition of amps, the Schiit would be properly called a modern high-resolution device. The ModWright becomes a darker denser comfort sound closer to current notions on vintage (just don't imply limited 50Hz to 15kHz bandwidth).
Woo Audio Model 5 with all optional parts upgrades [$4.000 total package]

LS100 vs. Model 5 SE: With the same Chinese 6SN7s in either amp—one pair 'routed' through Mosfets, the other through direct-heated triodes—and even 5AR4s sourced from the same supplier, these machines were virtual stand-ins on sound and price. The aural milieu was a virtual overlay, quite shockingly so to beliefs which would grant the 300B a mythical goal that's not approachable by other means. If I would ultimately give the Woo a very faint nod on textural sophistication and that very organic expand/contract sense of breath riding on a strong swell, it has to be understood as a very small lead indeed. In realsization mode I'd sell off the Woo as cloning the ModWright's flavor too closely. In that world there's no sense in owning two of a kind when the whole fun of multiples is the broadest possible variety without duplicates.

The Sennheiser and Audez'e cans responded alike which is to say they nearly couldn't distinguish between these amps. This was unexpected. My accountant—the one on permanent unpaid vacation—would undoubtedly applaud and point out the sagacity of investing into the LS100 as it includes a free $4.000 headphone amp. Put this way it gives one pause to reflect on Dan Wright's chops as a very crafty and astute designer.

Cannery Row: To wrap up headphone impressions, the LS100's 6.3mm jack was essentially tacked onto a voltage gain stage optimized to drive power amps and long interconnects. It thus benefits from a power supply that likely would be a lot smaller if transferred to a discrete headphone amp. Grafting onto the octal triodes a Mosfet buffer was a flash of genius as it isolates the glowing bits from the actual load, lowers the output impedance, avoids the high feedback of operational amps and runs devices which mimic valve behavior. The big potential issue of noise in this repurposed scenario was handled beautifully to be no issue at all. The upshot is top-class 300B sound without the expense and maintenance. When I say 300B sound, I'm referencing headphone drive with its high impedance, millivolts, no crossovers and one driver of two inches or less, not the usual miss-ery of attempting to control multi-way speakers with big woofers and reactive phase angles from such devices. 300B sound refers to how direct-heated low-power triodes perform under rather more idealized conditions.
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