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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 27" iMac with 3.4GHz quad-core Intel Core i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory, PureMusic 1.89g in hybrid memory play with pre-allocated RAM and AIFF files up to 24/192; Audirvana 1.5.10 in Integer mode 1, Metrum Hex, AURALiC Vega, SOtM dX-USB HD with Super-clock upgrade & mBPS-d2
Preamp/Integrated: Nagra Jazz, Esoteric C-03, Bent Audio Tap-X, Crayon CFA-1.2, Bakoon AMP-12R, Gato Audio DIA-250, Clones Audio 25i [on loan]
Amplifier: First Watt SIT1, Goldmund/Job 225, AURALiC Merak [on loan]
Speakers: soundkaos WAve 40 + Zu Submission, Boenicke Audio W5, AudioSolutions Rhapsody 200, German Physiks HRS-120
Cables: Complete loom of Zu Audio Event, KingRex uCraft and Light Harmonic LightSpeed and Zu split USB cables, Van den Hul AES/EBU cable, Tombo Trøn S/PDIF cable, AudioQuest Diamond Toslink
Headphones: ALO-recabled Audeze LCD-2, LCD-3, LCD-XC; Sennheiser HD-800; beyerdynamic T1 & T5p; AKG-K702; stock-cabled HifiMan HE-500 & HE-6; MrSpeakers Mad Dog and Alpha Dog; Aëdle VK-1
Headphone amps: Bakoon AMP-12R, April Music Eximus DP1, Stello HP100MkII [on review], Burson Conductor, AURALiC Gemini 2000 [on review]
 Stands: Artesania Audio Exotyeric for front end, Rajasthani hardwood rack for amps
Powerline conditioning: Vibex Three 11R on front end, Vibex Two 1R + GigaWatt power strip on amps
 Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review component retail in Europe: €1'499

As it so often does on this beat, the case began with an unexpected email. "I must totally agree with your Bakoon HPA-21 review. Great device, the best HD800 match I’ve heard thus far. This is about something similar. A couple of weeks ago a company called Questyle contacted me to ask if I’d be interested in reviewing their CMA800R headphone amplifier. Woo Audio WA234 mono aside, their CMA800R is the second deck I know that can work as a balanced mono headphone amp. It’s also current output and fully discrete. I heard many similarities between it and the HPA-21 on bass, detail and overall smoothness. I didn’t have both amps at the same time but I do remember the magic of the HPA-21. The Questyle did incredible things to the HD800 as well. It turns out that those headphones must really like a current output stage. Interested? Questyle has an excellent sounding technically unique device that works very well with the HD800. Could this be something worth your while? Truth be told, I’m a journalist, not a marketeer. Nobody asked me to contact you. Here’s my review. Aye, it’s in Polish. Sorry for that. I work for the Polish press." - Dawid Grzyb

Intrigued, I followed up with Questyle owner Alden Zhao. His view on CMA800R versus HPA-21 was interesting. "There's actually much difference between our machines. The Bakoon is more about current-mode 'transmission' whilst the CMA800R is about current-mode 'amplification'. They focus on current drive, we on internal current processing. The inputs and outputs of our machine operate in voltage mode for better compatibility. The HPA-21 uses no feedback but lists no stable distortion values. Our CMA800R does use a NFB loop. In single-ended output it already produces THD+N of less than 0.00038% whilst in monaural fully balanced mode that drops to below 0.00026%."
Plitron power toroid, 22 x Nichicon Fine Gold 1000uF/35V caps, Wima caps, Schottky rectifiers, Dale resistors, OPA627AM op amps, Alps pot
Having reviewed the Bakoon with its voltage-mode input since I didn't have a matching Bakoon current-output DAC; given that the HPA-21 has current and voltage mode outputs; and thinking that Akira Nagai's Satri circuit performs gain in the current domain... I didn't completely agree with Alden's depiction. But certainly driving its headphone load in current mode is the Bakoon's main appeal. Just compare its current and voltage outputs to know. Of course this sort of talk is best left to the engineers. My interest in the CMA800R was simply triggered by a fellow journalist who'd found it to outperform his AudioG-d Phoenix and to be of similar quality to the deck from Korea/Japan. At a price tag of exactly half this promised potential smiles.

With Audeze LCD-XC sitting on AURALiC Gemini 2000.
As Alden reported who by now was in the US for CES, "today I visited some hifi stores in San Francisco who all were interested in our products. That's great encouragement for us". When I told him that none of my 'phones use balanced cables to where I could probably stick to his CMA800 model, he disagreed. The 'R' version had superceded it. Hence that's what he'd send. Katherine Tan at Chinese HQ arranged for shipment and promptly emailed a DHL tracker. Both Alden and Katherine communicated in good English. This removed the mainland China barrier from the equation.

On that subject of Asian origins—many makers in Taiwan, Hong Kong and Korea actually manufacture in China, never mind plenty of US and EU brands—let's list April Music, AURALiC, Aurender, Bakoon, Eastern Electric, KingRex, QAT, Calyx and SOtM as a few easy examples of non-tube electronics makers who on build, fit'n'finish and sound have established very good reputations on par with Western brands whilst on price they often enjoy their cheaper labor advantage. In short, made in Asia no longer has to mean cheaply made and of dubious performance and reliability. There's absolutely nothing cheap about the €15'000 Aurender W20, the €6'500 Stello Ai700 or the €3'300 AURALiC Vega. Where in this picture would the CMA800R slot itself?