AshKMetrum Acoustics’ new Amethyst Digital To Analog Converter (DAC) follows on from the company’s Adagio DAC/preamplifier. The Adagio was the first integrated design from Cees Ruijtenberg and Metrum Acoustics, but the Amethyst moves in a slightly different direction. It still incorporates a stand-alone DAC and can therefore be seen as a follow up to the popular NOS Mini Musette DAC but here a headphone amplifier is directly coupled to the digital to analog conversion boards, providing dual functionality.
Amethyst incorporates the second generation of the company’s “Transient” digital to analog conversion process, moving from the Musette’s two DAC ONE to two DAC TWO modules.
With previous Metrum DACs such as the Octave and Hex models, increased processing power was achieved by doubling the number of digital to analog converter chips. Transient conversion follows this same principle in the DAC ONE range, but with DAC TWO, development at microscopic level has allowed the Transient converters to be condensed. Doubling the processing power therefore, requires no extra space to improve performance. In addition, the Forward Correction (FPGA) technology first seen in Metrum’s Pavane (in the form of a separate module), has also been miniaturised.
The result is that each of the new DAC TWO modules encapsulates two DAC ONE derivatives and also incorporates Forward Correction for each module and channel. Data flow has also been improved over the main board, and sampling rates run to 384kHz.
With its new casework, the unit offers the same compact dimensions as the Musette model, which makes it suitable for either desktop or main system use. Analog outputs are available for stand-alone DAC connection to a preamp or integrated amplifier, with standard 2V output. When headphones are connected, this function is muted.
Careful attention has been paid to powering the headphone output, with a 30VA transformer and 22,000uF capacitors. The new design increases available power to enable Amethyst to drive 16-Ohm headphones.
Specifications are as follows:
Frequency response : 1Hz – 20 khz -1dB @ 44.1 kHz , 1Hz – 65 kHz -1dB @ 192 kHz
Distortion : 0.006 % THD
Channel separation : 110 dB
Noise floor : -145 dB related to 2 Volt RMS
Output impedance : 100 Ohms. Headphone output 3 Ohms
Sampling rate : Optical : 44.1 – 96 kHz
Coax : 44.1 – 192 kHz
USB : 44.1 kHz – 384 kHz
Dimensions : 440 x 320 x 85 mm
Weight : 2.5 kg
Click here for more information on Metrum Acoustics’ Amethyst DAC. Local pricing is $2100.
? Note ? : Amethyst operates in ‘conventional’ analog mode – when amplification is required to drive headphones. When phones are disconnected all power is redirected to the Dac.