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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 2TB iMac 27" quad-core with 16GB of RAM (AIFF) running OSX 10.8.2 and PureMusic 1.94g in hybrid memory play with pre-allocated RAM, Audirvana 1.4 in direct/integer mode, Metrum Hex, SOtM dX-USB HD with Super-clock upgrade & mBPS-d2s, AURALiC Vega
Preamplifier: Nagra Jazz, Bent Audio Tap-X, Esoteric C-03, TruLife Audio Athena
Power amplifier: FirstWatt S1 monos, SIT2; Bakoon AMP-11R; Job 225; Clones 25i [on loan]
Loudspeakers: Aries Cerat Gladius, AudioSolutions 200, Zu Submission
Cables: Complete Zu Event loom, KingRex uArt split USB cable with Bakoon BPS-02 uninterruptible battery supply
Powerline conditioning: GigaWatt PF-2 on amps preceded by Vibex Two 1R, Vibex Three 11R on front-end stack
Equipment rack: Artesania Esoteric double-wide three tier with optional glass shelf, Rajasthani hardwood rack for 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: Starts at $299 + shipping; premium version with Takman REX/Zfoil resistors plus remote is $637 + shipping as reviewed
Typical. At audio shows, speakers, turntables and flashy amps get all the attention. That's because they make sexy visual statements. And men judge with their eyes so they also seem to matter most sonically. In this context where we strategically disregard cables as the drabbest of the lot, what could be unsexier than a passive preamp? Yet any hardware geek worth his pencil will concede that Arek Kallas' Khozmo passive is one sizzling sex pot. Once you flip its lid. And before you fret what in the above collage that lipstick-red Polish coat of arms signified, both the Pancin Art Technology VZ1 speaker and Khozmo Acoustic passive preamp are from Poland. This was just a sly little reminder in case this country wasn't yet on your map as a serious destination for hardcore hifi solutions which are engineered and executed to the proverbial Nines.

Arek's business is sex pots. Well, precision stepped shunt-type* attenuators. He does them in sixsome (6-channel), foursome (quad or balanced), twosome (stereo) and thensome (mono) flavors. He does them in Allen Bradley, Caddock, Dale, Takman or Vishay resistor flavors. He does them in 10/25/50/100/250Kohm** or custom impedances. Either way they cover from -60 to 0dB across 48 steps (that's in 2dB increments from 1-11 and 1dB from 12-48) with make-before-break switches, hard-gold contacts, ±0.1dB channel matching, just two resistors in the signal path at any given setting, CNC-machined PA11 aluminum bodies and a precision ball-bearing support.
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* A shunt attenuator uses one fixed series resistor (yellow Rin of the single-channel schematic) whilst the shunt resistor to ground is selected from one of many available values (orange Rg1 - 48). The actual output signal thus becomes a function of the voltage drop across the shunt resistor as the current flowing through it, making its quality as important as—or more so than—the series resistor.


** For my FirstWatt SIT1 transistor monos, Arek recommended his 10Kohm loading. Asked what the operational impedance window across all possible settings would be, he said from 10K to 110K.

For those of us not into DIYing or formal production, Khozmo Acoustic also offer passive preamps. Like a flexible lego, the front face can sport one central control (no input switching), two controls (stereo volume + input selector or dual-mono volume without switching) or three (dual-mono volume + input selector). The 3:2 i/o back panel can run as RCA or XLR. In the latter case the attenuator is the quad stack below. This sidesteps the conversion most active preamps commit which run balanced input signal through a single-ended volume control before outputting it again balanced.

As another choice you also have the above remote control with 30-dot two-digit display shining right through the fascia. This brief intro now segues straight into today's assignment. Arek sent me his stereo version with 3 inputs, two outputs and infrared wand. To make the world an even smaller place than it is already, his Khozmo Acoustic sells online direct with a shopping cart that includes very fair ship rates directly to your door ($49 to mine in Switzerland).

Atypical. Once you realize that the stereo unit sans remote starts at $299 + shipping, you'll finally agree even on the prior 'sizzling' bit. Given its bomb-proof construction and top-quality parts pedigree, this really might be the hottest resistor-based passive ever. Where it matters. Inside. The box itself is as compact as can be and though built to last, deliberately free of bling. With many of today's still affordable 'super' DACs either offering no attenuation at all like the Metrum Hex; or exclusively digital volume like the AURALiC Vega and Resonessence Labs Invicta; the Khozmo could just be what your personal doc ordered. Listen at all levels without resolution decimation.


What's more, splurge on the infrared wand and you needn't even give up on the creature feature of hot-seat commandeering. For the mondo splurge as I reviewed it, there's the Takman REX/Zfoil resistor version (quad stack with balanced outputs above). With remote that stereo unit sets you back all of $637. Here splurging is nearly synonymous with sanity. Think of that next time you laugh at a bad Polish joke.