Reviewer: Srajan Ebaen
Financial interests: click here
Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 12.2), PureMusic 2.04, Qobuz Hifi, Tidal Hifi, COS Engineering D1
Headphones: Forza Audio Works rewired Audeze LCD-XC and LCD-2, stock-cabled HifiMan HE1000
Headphone amps: Questyle CMA800R (x2)
Cables: KingRex uArt double-header USB; Zu Event
Power delivery: Vibex Granada/Alhambra on all components
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves and Krion or glass-based Exoteryc stand/s for amp/s

To simplize or simplificate? A good question for 2015's Headfi Hamlet. Of course we could just simplify, win the spelling bee and be done with it. But where's the fun in that? Today's curiosity is about balanced headphone drive. Aside from reading impressive on paper, does it do anything to/for the ears? It'd be simplistic to make far-reaching statements from a single experiment. And that's all we'll do today; one experiment in two parts. Far-flung claims remain for those with far more experience flung onto this exotic subject.

We'll use one or two €1'500/ea. Questyle CMA-800R balanced amplifiers, then pairs of Audeze LCD-XC/LCD-2 with Forza Audio Works Noir cables, one terminated 6.3mm, the other dual 3-pin XLR but otherwise based on identical conductors and geometry; plus a pair of HifiMan HE1000 with stock 6.3mm and 4-pin XLR cables, the latter shaking hands with a cable adaptor splitting into 2 x 3-pin XLR as shown above.

That's because, unusually, these Chinese headphone amps can be strapped to mono. Now each amp drives just one channel of any headphone that's properly wired up without sharing a ground between its two drivers as is the norm.

One minor pesticle in this particular Questyle scheme? One ends up with dual-mono volume controls. Hopefully the audible gains would make up for this minor inconvenience; and the far greater misfortune which strikes the piggy bank in case of wanton desire. Smash. Oink?

Converting from stereo/normal to dual-mono/balanced drive is easy. Instead of connecting XLR interconnects from DAC to the L/R XRL inputs of one CMA800R with mode toggle set to stereo, I'd move them to the 'full bal input' of each, then flick their mode toggles to mono.

Allocating two amplifiers to this task is admittedly excessive. Any number of stereo headfi amps including portables provide the socket/s necessary for what's called balanced drive. But Questyle do offer this extra 6th gear as do Woo Audio with their flagship model. Bridging usually doubles or quadruples power output*. Routinely it offers even lower distortion specs. In my scenario then, it would be perfectly impossible to assign sonic differences to just balanced drive in isolation. Any of the following mono factors would factor in tandem: more power; possibly lower distortion; discrete power supplies per channel. That's why no general conclusions should be drawn from my outcomes. They apply only to this specific experiment as they are not the pure result of merely balanced drive. Packing all of that detail into one pert header was impossible though. Hence my "brief inquiry into balanced headphone drive" as I promised at the top is not exactly what it appears to be. That would be rather too - well, simplonic to conclude my variations on butchering the word.

* In this instance power delivery ups x 4, distortion becomes an ultra-low 0.00038% and one would expect channel separation to be absolute over the stereo version.