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Srajan Ebaen
Financial Interests: click here
27" iMac (3.4GHz quad-core IntelCore i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory); PureMusic 1.87; Amarra 2.3; Audirvana Plus; April Music Eximus DP1; Esoteric/APL Hifi UX1/NWO-M; Audiophilleo 2, Burson Audio DA-160
Preamp/Integrated: ModWright LS-100 with Psvane CV-181T tubes, Esoteric C-03, Bent Audio Tap-X
: First Watt SIT1 monos, ModWright KWA 100SE
Speakers: Aries Cerat Gladius, Boenicke Audio B10
Cables: Complete loom of Zu Audio Event, KingRex uCraft USB cable with UPower battery supply, Stereo
lab Tombo Trøn BNC/BNC coax
Stands: Artesania Esoteric double-wide 3-tier with optional TT glass shelf, 2 x ASI HeartSong amp stand
Headphone amps: ModWright LS100, Ex
imus DP1, Burson Audio HA160DS,
Burson Audio HA160, Linnenberg Audio u:c:a [on review], HifiMan EF-6 [on review]
s: HifiMan HE-5LE, HE-500, HE-6 (with optional Entreq Konstantin 2010 replacement harness); Sennheiser HD-800, Beyerdynamic T1 and T5p, Audez'e LCD2 all recabled by ALO Audio; Ortofon eQ7

Powerline conditioning: 1 x GigaWatt PF2, 1 x Furutech RTP-6
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: €940

Only the simplest can accommodate the most complex. Visit the 47lab website. That's the very Zen and intellectually elegant motto which greets you there. To appreciate its fierce mojo, read the specs for the Model 4706. It's known also as the Gaincard, the one that spawned the entire DIY Gainclone phenomenon. "World's smallest number of parts, 9 per channel excluding attenuators. World's shortest signal pass length, 32mm including length of the parts." Whoa. If simpler really is muchos más betta as uncle Albert gets quoted so often, how could anyone beat that? Game over. Gaincard for lifetime office.

As do many others—Nelson Pass immediately comes to mind with his FirstWatt models—team Burson agrees with the basic concept of circuit simplicity. They'd question though any blanket presidential nomination where operational amplifiers or amps on chips are involved. They'd ask us to consider what's inside such opamps. Take TI's NE5534 for example. Stuck inside an eight-legged casing smaller than a digital camera memory card hide 53 miniature components which make up a complete amplifier circuit. Meanwhile Burson's input board for their original HA-160 headphone amp runs on 32 discrete variants. Which really has the lower parts count: one small opamp or an entire far larger PCB?

The Burson board minimalizes the opamp with a KO. The opamp only wins if signal-path simplicity—which this context makes synonymous with signal purity—equals shortest path length as measured in millimeters. If simplicity gets defined as lowest number of functions embodied by parts (regardless of whether those be discrete or integrated), it loses. And all that is prior to worrying about the quality of miniaturized bits versus full-sized bobs. Or high amounts of feedback versus less or none. Or current flow across tiny vapor-deposited aluminum traces versus fat copper. Careful parts selection and matching. Noise effects from extreme proximity.

10 power and power supply transistors mount directly to the bottom panel, turning the entire case into a heatsink.
The output stage runs in parallel single-ended mode.