Esoteric D-05 32-bit stereo D/A converter / pre-amp

Digital audio has made strides in a frantic pace since its commercialization in the early 80s, when the industry abandoned engineering resources for perfecting the compact cassette and analog turntable media, and instead focused on advancing the state-of-the-art in the compact disc medium. The result was a convergence of talents and ingenuity the likes of which not only happens once in a lifetime, but one that has continued to preoccupy audiophiles and industry alike in its evolutionary stages to this day.

Esoteric Company began developing and introducing high-end digital audio disc players since its formation in 1987, as a continuation and progression of the efforts of Teac, its parent company. It was in this year, with the introduction of a type of compact disc transport mechanism named VRDS, short for “Vibration Free, Rigid Disc Clamping System”, that cemented the company’s leadership position in the digital audio segment of the industry. The company ventured into system engineering in recent years and introduced a complete Esoteric system comprising not only the digital source but preamplifiers, power amplifiers, phonostage, speakers and even Esoteric MEXCEL cable systems. In speaker development, Esoteric partnered with Tannoy and introduced a floor standing MG20 and a bookshelf MG10. In amplification, it started at the top with the introduction of five models ranging from the E-03 phono stage at $5,900 to the A-100 3-stage tube amplifier at $22,000.

The subject of this review is D-05, a D/A converter released in 2007 as part of a series in commemoration of the company’s 20^th Anniversary, is unique in its adoption of the Asahi Kasei Microsystems AK4397 DAC chip. I reviewed a modestly priced DAC in 2007 that utilized the company’s AK4396 chip, a 128-times oversampling, 120dB 192kHz/24-bit chip, and I thought it set a benchmark for affordable DACs. The AKM 4397 in the D-05 is now a 32-bit processing unit with “fully extended 32 bit processing throughout all stages, including digital filter and the Delta-Sigma modulator”, and also equipped to process DSD signals. According to the AKM brochure:

“The AK4397 is a high performance premium 32bit DAC for the 192kHz sampling mode of DVD-Audio including a 32bit digital filter. Using AKM’s multi bit architecture for its modulator the AK4397 delivers a wide dynamics range while preserving linearity for improved THD+N performance. The AK4397 has full differential SCF outputs, removing the need for AC coupling capacitors and increasing performance for systems with excessive clock jitter. The AK4397 accepts 192kHz PCM data and 1-bit DSD data, ideal for a wide range of applications including DVD-Audio and SACD. The AK4397 has a functional compatibility with the AK4393/4/5 and lower power dissipation.”

Esoteric was the first company to take the AK4397 chip set in a dual-mono configuration from the commercial/professional markets into the consumer markets. In addition, the company’s recently released $5,800, 4-device-in-1, SA-50 SACD/CD player is equipped with another of AKM’s 32-bit chip sets and is also dual-mono in configuration, the AK4392.

AKM’s data sheet shows the AK4397 chip to feature the following:

·         128x Over sampling

·         Sampling rate: 30kHz to 216kHz

·         32-bit 8x Digital Filter

·         DSD data input

·         Digital De-emphasis for 32, 44.1, 48kHz sampling

·         Digital Attenuator (Linear 256 steps)

·         Mono Mode

·         External Digital Filter Mode

·         THD+N: 103dB

·         DR, S/N: 120dB

AKM’s AK4392 brochure also has the following to say about the chip set in the SA-50:

“AK4392 is a 32-bit DAC, which corresponds to DVD-Audio systems. An internal circuit includes newly developed 32bit Digital Filter for better sound quality achieving low distortion characteristics and wide dynamic range. The AK4392 has full differential SCF outputs, removing the need for AC coupling capacitors and increasing performance for systems with excessive clock jitter. The AK4392 accepts 192kHz PCM data and 1-bit DSD data, ideal for a wide range of applications including Blu-Ray, DVD-Audio and SACD.”

The part I like the most about this, which I think is a good move on Esoteric’s part, is that there are two AKM 4397s in the D-05 – one for each channel and on separate L+R decoder boards. To compliment this dual-mono DAC arrangement, Esoteric adorned the unit with dual-mono power supply and analog components, including a large toroidal transformer for each channel as well. This lays the ground work for a potentially, completely tricked out system in full extraction of every last precious bit of information as converted by the AKMs.

Of course, Esoteric would recommend the use of its P-05 matching SACD/CD transport in order to enjoy the benefit of the D-05 fully, and vice versa. But I am using the $30,000 47 Laboratory 4704 PiTracer CD transport, and I naturally must know how the cheap D-05, with all its capabilities, may fare in my system first. On its own, the D-05 already offers a slew of exciting functionalities, such as a choice of 1x oversampling, 2x oversampling and 4x oversampling. For the readers who prefer the DSD performance, the D-05 up-converts incoming signals into the DSD mode as well. The D-05 offers two stages of phase lock loop for jitter reduction when used in conjunction with a CD transport other than matching P-05. Last not least, you can also select a slow rolloff digital filtering effect labeled WIDE for “reproducing natural sounding harmonics", and a sharper rolloff setting named NARROW for “sharp sound images”.

Other functions offered by the D-05 include WORD SYNC, for receiving a master clock signal when used in conjunction with Esoteric’s G-03X ($4,500) or G-0Rb ($18,500) Master Clock External SYNC Generators. Concurrently, the D-05 can also generate its own master clock signal for synchronization with compatible transports, including the company’s own P-01 ($31,500), P-03 ($16,500), and the matching P-05 ($8,400).