Etalon Sound Dream DAC review is coming

Another interesting product has landed and Mono and Stereo headquarters. The Etalon Sound Super R2R DAC... Etalon writes: "This is a DAC for those who are looking for a rich, warm, natural and beautiful sound, similar to a live performance.
DAC can convey all the wealth, character, timbre and depth and the smallest nuances enclosed in the source material, so precisely that you want to listen to music again and again

The Dream DAC is the realization of our intentions to transmit initial characteristics of digital sound record into a real, natural sound. Such operations as amplifying with nonlinear elements, oversampling, transmitting of digital signal via industrial microchips or through the USB tract interfere on signal making it different with its original.

The Dream DAC is free of any negative influences of an amplifying the sound after conversion. You can get natural sound without any interferences that could be brought in by filters or preamp circuitry. There is no any harmonic distortion from amplifying at all. The Dream DAC is based on our laboratory developments. The main of them is Super R2R technology. Each Super R2R matrix is an active matrix, so at the result, the DAC is power DAC, with spirited live sound, able to drive headphones or an AMP without a preamp. Total number of power elements of matrixes is over a hundred. There is a system of synchronous volume control for using DAC with headphones.

Super R2R technologies enable to approach to an absolute sound fidelity and it stands on the highest quality level obtainable by digital-to-analogue conversion in principle. These technologies are protected by patents and applications for an invention.

Technical characteristics and particularities description:

New synchronous volume control

Another advantage of Super R2R technology is synchronous volume control. There are two fundamentally different approaches to volume control in Hi-End — a digital and an analogue one; each has its own major flaws. We designed a new way of volume control suitable just for the R2R array. It’s neither digital nor analogue in the current interpretation of these terms. It is based on synchronous changing of the logic value of ‘1’ reference voltage in the converter and enables to control volume without changing original digital code. At the same time is has no drawbacks inherent in the analogue control method.

Converter based on balanced R2R circuit

R2R circuit is a classic converter layout realizing the most accurate way of digital-to-analogue conversion.

The sound of R2R array based converter without oversampling (NOSDAC) is more natural than the one achieved by means of other circuits with oversampling and digital filtering.

Classic R2R array has a flaw associated with the problem of signal conversion while virtual zero crossing. At this moment all logical circuits are switched simultaneously and even tiny non-synchronism causes an overshoot of stray impulses (the so called glitches).

In Super R2R virtual zero crossing poses no problem because R2R arrays have balanced discrete sign-magnitude hybrid ladder topology. Positive and negative half-waves of the signal are processed independently, each by a separate array and are mixed only at the output. As the result there’s no virtual zero crossing at all and no corresponding problems!

Power supply

DAC power is divided into digital and analog and is implemented on 3 custom-made toroidal transformers. To power each R2R board, a special power supply was developed, consisting of stabilizers, wetlands (Virtual Battery Device) boards and a Double Ring Capacitor of its own production for final power filtration

A new algorithm for low level signals conversion

This new algorithm enables to fulfill the sound potential of low amplitude signals that otherwise are reproduced either with distortion or remain completely obscured by noise and inaudible.

The new algorithm for low level signals conversion is realized by means of a three-stage circuit; a single R2R array is divided into three parts. Each part is a separate R2R converter processing its own fraction of the signal — having either low, medium or high level. The low level signal ends up being shaped by a chain of not 24 resistors the way it’s done in the conventional R2R converter (with 24 digit capacity) but by 8 resistors only resulting in a dramatically shortened signal path. This technology provides for a careful handling of any low level signal.

Besides the digital code’s least significant bits get an additional gain before conversion and are again brought to normal level afterwards.

All in all the new algorithm makes the low level signals noise-free and maximizes DA conversion authenticity in the most important area of low amplitude signals.

Galvanic decoupling of digital and analogue converter units

Galvanic decoupling by means of a transformer provides full separation of digital and analogue converter circuits preventing from sound quality deterioration by noise and distortions. Transformer cores are made from iron-based nanocrystaline alloy, a new generation material with extraordinary properties. Winding elements are made from ‘symmetrized’ litz wire. The use of nanocrystalline iron alloy combined with ‘symmetrized’ litz wire made it possible to design sound transformer, a new generation device with specs and efficiency previously inaccessible.

TUC USB Module

TUC (True USB Conversion) USB Module developed by us provides not only for a transfer of data from computer to DAC but also for a feedback to control this transfer process. TUC is realized on FPGA, high-precision clock generator (Femto clock) and signal buffer. It uses a unique algorithm for generating I2S signal. High-precision clock generator has minimal phase noise and is located in close proximity of the converter.