Reviewer: Edgar Kramer
Source Digital: Sony XA-5ES as transport; Bel Canto Designs DAC 2
Source Analogue: Pro-ject 6.1 turntable with Pro-ject arm and Goldring cartridge
Preamp/Integrated: Blue Circle BC21.1 with Shallco attenuator option; Supratek Sauvignon with NOS RCA and Sylvania tubes
Amplifier: Gryphon Tabu 2/100 power amplifier; Blue Circle BC26 MKII power amplifier
Speakers: Wilson Watt Puppy System 6
Cables: Harmonic Technology Magic Digital; Harmonic Technology Magic and Truthlink; DanA Digital Reference Silver; Eichmann eXpress 6 Series 2 interconnect cable; Harmonic Technology PRO-9+ loudspeaker cable; Harmonic Technology Fantasy AC; Shunyata Research Diamondback power cords, Eichmann eXpress AC power cable
Stands: Lush 4-tier, partly sand-filled
Powerline conditioning: PS Audio P-300 Power Plant
Sundry accessories: Black Diamond Racing cones; various custom cones and shelves and mysterious rubber compounds, Stillpoints ERS paper in strategic positions around DAC, Shakti On Lines; Densen CD demagnetizer; Auric Illuminator CD Treatment
Room size: 16' W x 21' D x 10'/11' H [stepped ceiling] in short-wall setup, room opens to adjoining office room
Review component retail: US$3,500, balanced outputs, calibrating microphone and other options available | PDC-2.6 without preamplifier option is US$3,000
Back to the Future
Do you recall my review of the superb Supratek Chardonnay valve preamplifier from a few months ago? I was extremely impressed with all aspects of the unit, the ideas and philosophies pertaining to its execution, its masterful build and aesthetics, the more than reasonable asking price and of course its superlative sound. The Chardonnay was subsequently awarded the prestigious Blue Moon Award.


Why start a review of the DEQX (pronounced dex) PDC-2.6P with a preamble on another preamplifier? Well, when reviewed back to back, the design and ideology chasm separating the units is so vast and the method of arrival at the common destination of music so dissimilar that I found it striking and fascinating and therefore, compulsory to note.


The Chardonnay's valves burn with an inherent transcendental light that harkens back to years gone by, indeed to the very founding of the age of reproduced sound. Yet this aged technology has been revived and implemented with the best of modern ingredients, up-to-date circuits and techniques by a designer with a passion for live music, industrial beauty and craftsmanship.


In contrast, the simple yet elegant DEQX PDC-2.6P is at the heart of the cutting edge and redefines it in turn. The DEQX is a time machine in a one-rack-space box. Its chronological dial reads "21st Century: 2004 and Forward Only". It is a state-of-the-art "clean slate" product, unique in its sophistication and originality. Designer Kim Ryrie implemented it with just as passionate a fervor as his stable mate integrated his valves. He challenges us to join him and go forth into the future of audio as he envisions it.

Kim Ryrie is no stranger to high technology and digital equipment. Having founded the magazine Electronics Today International in the mid 70s, Kim also cofounded the world-famous and way-ahead-of-its-time Fairlight CMI firm, the legendary Australian manufacturer of high quality digital keyboards/synthesizers named after the hydrofoil ferry Fairlight that scurries across Sydney Harbour and on to our Northern Beaches. At the time, Kim's unique technology was nothing short of revolutionary and musical techno visionaries such as Alan Parsons, Peter Gabriel, Thomas Dolby, Kate Bush and Keith Emerson -- to name but a few -- were keen to embrace this cutting-edge technology.


Zoom forward to the present in Kim's time machine and find a growing number of high-profile loudspeaker manufacturers and contemporary audio visionaries adopting DEQX processing technology in their designs, most notably the gorgeous new NHT Xd range of Hi-Fi loudspeakers, the Manger-fitted Overkill Audio speakers which were designed around the recommended use of a modified DEQX active crossover [to be reviewed by our Editor in the new year] and the M60 and M80 professional monitors. Further notoriety comes via Abbey Road Studios where DEQX technology has been adopted in their mastering and production processes.

So, what is this Digital EQ and Xover and what does it do? The PDC is a high-quality PC-configurable DSP preamplifier with the following operational features listed in a topsy-turvy signal-flow basis:
  • A digital-to-analog converter with S/PDIF coaxial and AES/EBU XLR inputs and 96/192khz 24-bit conversion
  • A 2 input, 6 output preamplifier with analog volume control and full-featured custom remote control
  • An active phase-correct (zero phase shift) digital crossover with 6 to 300dB/per octave slopes
  • Digital loudspeaker correction with individual driver analysis and ultra-accurate time alignment, phase and frequency response error correction
  • Digital room correction/measurement
  • Real time 10-band minimum-phase digital parametric or graphic equalization

Have you ever owned a Swiss Army knife?


Clear the DEQX - or, Where do I start?
I will first describe the physical features of the DEQX PDC-2.6P. As the images depict, the unit is deceptively simple in appearance and of modest build when compared to the likes of the Krells and Mark Levinsons and Jeff Rowlands of this world. The front panel is uncluttered and starting from the left, sports a standby button/LED, then a two-section rocker switch with a central multicolored LED for volume control confirmation. The volume LED changes from off (-120dB) to a mesmerizing rainbow kaleidoscope of colors that change depending on the level of attenuation. Finally we get to the three profile buttons. Each of these activates user-stored post-calibration settings or profiles in the PDC's memory bank for instant recall. There's also a bypass position for totally uncorrected, un-equalized "straight-thru" playback.


The rear of the unit includes in order of appearance: an S/PDIF RCA connector; a USB port for connection to a computer (mandatory for calibration); AES/EBU connection; a RS-232 computer connection and daisy-chain output; a calibration microphone input with available phantom power for condenser microphones; a balanced XLR audio input; an unbalanced RCA input; three unbalanced RCA outputs (spaced a little too closely together); three balanced XLR outputs (optional); a power switch and an IEC receptacle. Also optional is a digital output for those wanting to use the unit between transport and DAC.


And now to the hard part, attempting to summarize as briefly yet succinctly as possible what the manual takes nearly 200 pages to describe. My Reader's Digest version follows.