X-FACTOR REFERENCE DAC

The new X-Factor Reference, 100kg two chassis ultimate take on digital to analog conversion from Russia. 

Digital-to-analog converter. It would seem that the device was already known a little more than 3 decades ago, and since then a lot of them have appeared.

So why another one?

The idea of ​​its creation was born gradually, during many years of working with High-End audio. During the operation of DACs of the highest level, a list of requirements, both sound and functional, was gradually formed, which, ideally, such a device should meet. Unfortunately, there were no models on the market that fully met the entire set of these criteria. The current situation is not new (as it once happened with cables), so the idea of ​​creating a more advanced DAC has firmly established itself in our engineering mind.

We have developed the most audiophile design based on solutions that are separately found in equipment from other manufacturers, but are not combined into one device! This applies not only to sound but also to the functionality of the device.

As a result of long-term research and repeated control listening in the reference path, the designs and the choice of elements for each node were finally worked out and approved.

In addition, our DAC has a modular design, which means it can be upgraded for new digital audio formats.

We would not be so confident, offering our product, if the correctness of the choice had not been proved for ourselves during numerous listening sessions, including comparative ones - with the recognized leaders of the High-End audio market.

Structurally, the product consists of two blocks with a total weight of about 100 kg (!): The DAC unit and the power supply unit.

In the audiophile environment, the debate about which type of converter is better - one-bit or multi-bit is not abating. For a correct comparison of the advantages and disadvantages of these solutions, they would have to be tested in one device. Otherwise, there are too many variables in the equation.


Until recently, there was no such opportunity, but today it has appeared!

There are two types of conversion at the same time in the device. They are implemented on a delta-sigma chip AK4497 / 4499 and a multi-bit BB1704pk. Moreover, the user can choose between them, literally without interrupting listening. In addition, an automatic mode is possible, when the multi-bit option is in priority (our choice), and when a DSD signal arrives, the device itself will switch to one-bit.

Important: one-bit microcircuits are used separately for each of the channels, and not one for two channels, as is often done.

The features of this DAC include the ability to choose from four coefficients of resampling of the input signal and four options for a digital filter: these are 16 sound options. Moreover, the values ​​of these settings are selected individually for each of the inputs and stored in memory. The digital filter can also be turned off completely. All digital signal operations are handled by a dedicated ADSP 21489 floating-point processor. This allows, among other things, to implement filters with arbitrary characteristics, including a custom one, which can be ordered by the client based on his requirements.

The device is equipped with a high-quality clock generator for external sources. BNC connectors for their connection are also installed on the rear panel. Its significance for music reproduction is very great. The use of a single oscillator for the source and DAC improves conversion accuracy and reduces jitter.

There are up to four independent generator outputs in the word clock and master clock formats. Moreover, the device automatically recognizes the format of the input signal and, following it, selects the optimal clock frequency of the reference generator.

The generator board itself is thermally stabilized. Its current warming upstate is indicated on the display of the device.

A group of input connectors is located on the top of the rear panel. Their specific configuration is chosen by the customer. There are two USB inputs and up to 6 XLR-RCA inputs. Moreover, the latter can receive a digital signal, either over one cable (SPDIF format) or over a pair of cables (SDIF format). In the latter case, the signals of the right and left channels are transmitted to the device separately, which provides twice the bandwidth of the transmission channel.

Among well-known audiophile companies, such a solution is used by DCS, WEISS, AURENDER. Professional equipment is equipped with such a protocol very widely. In total, up to three SDIF inputs and up to six SPDIF inputs can be implemented.

All analog circuits at the output of the converter microcircuits are made on discrete elements and operate in deep class "A" in single-cycle switching.

Suffice it to say that the output buffer has a quiescent current of about 300 mA and an output impedance of a few ohms, in the absence of feedback. It is essentially a small power amplifier! Output stage bandwidth - 0 Hz to 50 MHz! At the same time, he demonstrated stability in work with the most "complex" cables.

All capacitors in the power circuits - audiophile series and electrolytic ones - are shunted with high-quality film ones. Resistors in analog circuits are also specialized.

All external switching of the device is made on connectors of the Furutech company (Japan), and the power connections between the power supply and the DAC are on Russian silver multi-pin connectors of the "military" series.

All the main functions of the device are controlled by a multifunctional remote control, made in a one-piece milled aluminum case.

At the request of the customer, a renderer with ROON control can be built into this DAC, as well as a volume control unit on discrete resistors. Moreover, this can be done after the purchase of the device by the user.

The case design also deserves a special mention. When creating a reference class technology, the quality of the case is very important, since the case performs many functions. The first place among them is the functions of protection against vibrations and electromagnetic shielding of the internal blocks of the device.

The cases of both the power supply unit and the DAC itself are made using a combined technology. The inner case, on which all the elements of the device are located, is made of steel, and the outer one is made of 14 mm aluminum sheets. This combination of magnetic and non-magnetic materials allows you to achieve the maximum degree of shielding of the product, both from external interference and nearby components from interference from the DAC. It should be noted that inside the case the analog part is additionally shielded from the digital one.

The power supply is connected by three power cables to the main unit.

Special attention has been paid to cable shielding and vibration protection in the design of the cables - this is a full-fledged component of the system.

In general, power is given special importance in this device, because the output signal is ultimately a "modulated power supply"!

As a result, a design was born, where each DAC node is powered from its transformer with subsequent stabilization (often double).

The solution, which seems redundant from a pure engineering point of view, nevertheless provides a tangible increase in the subjective sound quality. In addition, all transformers (and there are only eighteen of them) are calculated based on a magnetic flux of 0.6 Tesla (usually this parameter is chosen in the 2 Tesla region) - this allows using the core in a lightweight mode, which, in turn, dramatically reduces the level of radiation transformer and its sensitivity to constant voltage in the network, although it leads to an increase in its weight and dimensions. All transformers are carefully shielded!

And like the "icing on the cake" - there are two power supply inputs on the block: for the digital and analog parts, which allows connecting from different sources/filters and achieving maximum mutual isolation.