ЦАПы — Musician Audio Aquarius

The Aquarius is a balanced resistor-ladder DAC made by Musician Audio in China. It was listed at USD 3,199.99, and its aluminium case is CNC-machined. It replaces the usual delta-sigma chip with discrete R2R networks steered by programmable logic, and it accepts every common PCM and DSD format from computers, streamers and disc transports.

Key specs that matter

USB and the two I2S inputs carried over HDMI accept PCM up to 32-bit and 1536 kHz and native DSD up to DSD1024, whereas the AES/EBU, coaxial and Toslink ports are limited to PCM up to 24-bit and 192 kHz, and every input handles DSD64 by DoP. Outputs are XLR and RCA. With PCM at 0 dB and 1 kHz the XLR output reaches 3.59 V and the RCA output 1.79 V, dropping to 2.66 V and 1.33 V with DSD. Musician Audio quotes A-weighted THD of 0.002% from XLR and 0.01% from RCA, a signal-to-noise ratio of 128 dB balanced and 123 dB unbalanced, dynamic range above 121 dB, crosstalk of -110 dB and output noise of 1.3 microvolts balanced and 1.2 microvolts unbalanced. Frequency response runs from 10 Hz to 58 kHz on both outputs.

Engineering and use context

Per channel, a dedicated high-speed FPGA controls four R2R networks, built from ladder rails of discrete resistors hand-matched to 0.005%. The ladders provide native 24-bit PCM decoding, and an additional ladder handles 6-bit DSD processing with 32-step FIR filters. An Altera Cyclone IV FPGA and an ARM STM32F446 processor manage the signal and control functions, and two separate oscillators serve the 44.1 kHz and 48 kHz sample-rate families to lower jitter. The owner can switch between non-oversampling operation and a 16x oversampling mode with the maker's own digital filters. The maker advises about 300 hours of burn-in with the unit left powered or in standby, and the warranty runs one year. The chassis measures 330 x 300 x 75 mm and weighs 5.6 kg, and the internal supply accepts mains from 115 V to 230 V at 50 or 60 Hz.

Pairing

The fixed-level outputs feed a preamp or an integrated amplifier's line stage, and the balanced connection is the better choice when the amplifier offers XLR inputs because it delivers the lower distortion figure. The I2S ports allow direct links to streamers and transports with matching HDMI-based outputs, bypassing S/PDIF conversion.

Alternatives

The Musician Delphinus is a smaller and cheaper R2R converter from the same maker with the same USB and I2S format support in a 200 x 195 x 45 mm case.