Abraxas – Tube DAC & Bluetooth 5.0
In designing Audiozen’s new DAC, we took our cue from our own idea of sound gained over the years and from the demands of our customers. We did not dwell only on the nameplate data of chips with astonishing performance; rather, we listened, we tried, and we chose.
We chose the best sound, and we did it in our best way, equipping the DAC with an equally modern Bluetooth 5.0 receiver to listen to HD music from your mobile device.
Both digital circuits are connected to the tube output stage that implements the ICCF configuration designed by Audiozen.
Abraxas is a DAC and a 5.0 bluetooth receiver composed of two chassis: the separate power supply unit has long been the flagship of Audiozen creations, giving them unparalleled value for money as well as first-class performance.
Digital Core 2
The Digital Core 2 combines together two sections: the USB interface and the DAC.
Neutrik’s prized USB type B socket delivers the digital stream to the digital interface (connected to three high-precision oscillators to ensure better performance) that handles the input data.
It is important to note that this interface receives its operating voltage directly from the Abraxas’ separate power supply stage and not via USB: in fact power supply socket contact is not connected.
Cirrus Logic CS4344 is the heart of the DAC: it integrates fourth-order multibit delta-sigma modulator and a linear low-pass filter.
This is an excellent DAC and it expresses itself excellently in the configuration chosen for Abraxas, returning in the better way every musical detail to the listener.
Specific attention has been paid to the Master Clock circuit, which is responsible for the reliability of the conversion: the high-quality quartz resonator is connected to the temperature-stable oscillator stage. To preserve the excellent functionality of the conversion stage and to limit its temperature excursion, all digital circuits are protected inside the elegant 3 mm thick perspex case.
Bluetooth 5.0 receiver
You can choose the source you want to listen to by switching to the DAC/BT knob on Abraxas’ front panel: the switch instantly turn off the circuit that is not being used, thus avoiding interference and ensuring reliability.
By switching the knob to BT, the Qualcommtm chip will ensure APTX HD (an upgraded version of the APTX codec) playback: it supports hi-res files up to 24-bit/48kHz and a bitrate of 576 Kbps compared to APTX’s 352 Kbps.
APTX HD standard is designed to improve signal-to-noise ratio and total harmonic distortion (THD) just to obtain comparable if not superior performance to CD.
Before reaching the tube output stage audio signal is preamplified (+3 dB) by a sophisticated Analog Devices dual op-amp, for a better dynamic range.
ICCF tube output stage
A tube circuit must give the benefits for which the tube itself is hailed by audio enthusiasts: one above all is musicality.
The ICCF tube output stage developed by Audiozen allows the Abraxas to achieve great naturalness in listening, instantly making the idea that the source is a sequence of bits disappear.
ICCF uses a dual triode tube per channel, polarized to obtain a very low output impedance, so as to improve matching with the device to which the Abraxas will be connected.
The constant current generator, connected to the triode receiving the audio signal, makes stable the tube operation, so that every musical nuance can be expressed to the fullest.
After careful evaluations in order to treat the audio signal in the best possible way, we chose the excellent ClarityCap ESA series polypropylene capacitors: Abraxas is equipped with two of that excellent capacitors per channel, connected at the input and on the output of the ICCF circuit.
All the rest of the components used are no less than that, making the Abraxas unbeatable in value for money.
Separate power supply unit
Audiozen has always placed great care and importance on power stage, dedicating to it the proper space, and physically separating it from the Abraxas delicate active circuits.
Inside the separate power supply unit are located two toroidal transformers, 60VA each, which is 20 times more power than is required by the digital and analog circuits inside Abraxas.
New integrated circuits are used to stabilize voltages of digital circuits, with vastly improved tolerances over their predecessors.
The excellent connection to the main unit is provided by professional connectors, provided with contacts designed to carry currents 30 times higher than those in the Abraxas.
Audiozen Abraxastube DAC & bluetooth 5.0
Tube DAC & Bluetooth 5.0 receiver
USB interface chip: CM6631A True high-speed audio processor
DAC chip: Cirrus Logic CS4344
Bluetooth chip: Qualcomm QCC3034 APTX HD
3 x coax inputs - 1 x USB input @ max 24bit/192 Khz
NOS tubes: 2 x ECC82 (or equivalent)
Toroidal transformers: 2 x 60 VA
Available finishes: silver & black
Main unit dimensions and weight: 348x98x295mm (WxHxD) – 3,6 Kg.
PSU dimensions and weight: 240x98x295mm (WxHxD) – 4,2 Kg.