Amethyst R2R DAC



Offering an alternative to that of Aurix’s Transformer Volume Control … an integrated design by Metrum Acoustics.

Two DAC TWO Modules which provide plenty of processing power and substantial energy reservoirs … to provide smooth and efficient delivery of power.

Conventional analogue volume control … directly coupled to D/A output board ensures – detailed quality sound.

However, the icing on the cake … is that the Amethyst by Metrum Acoustics also has the ” looks “ to partner what’s inside.

The Amethyst is our new entry model using our praised “forward correction technology“. Due to this technology a real 24 bits performance is realized and probably the most advanced way to give R2R technology new dimensions. As a result music will be more exiting as details on very low levels will be audible. The Amethyst can meet the best systems today in terms of sound quality as it borrows all the good things from our top models Pavane and Adagio.

Like her predecessor the Amethyst is designed for the same basic frame but electronics have been redesigned for future tasks. In addition we have implemented a new and powerful headphone amplifier having its own volume control.

The Amethyst is using two Transient R2R ladder Dac TWO modules. These modules can handle extreme high sampling rates but are limited to current industry standards which has its maximum (384kHz) on the USB input. The result of this process is an extremely fast and accurate behavior and brings listening experience on a much higher level.

Despite the fact that both dac modules are build on the same board an extremely high channel separation of 110 dB is realized. This contributes to flawless positioning of instruments. The headphone amplifier will drive impedances down to 16 Ohms and gets his power from a powerfull 30VA power supply. When the the Amethyst is used as a dac this power will be available for the DAC only.

Trickle down technology from Adagio and Pavane Level III, is now available at a most affordable price. A volume controlled Headphone output almost comes free.

The DAC TWO modules each incorporate Forward correction technology to both channels. This approach is ideally suited to R2R design and maximizes performance, providing true 24 Bit performance. As with the Reference models, this allows for retrieval of very low level information/detail.

Even though Amethyst is a small ‘mini’ integrated design, incorporating both Digital and Analogue processing, channel separation is specified at 110dB. This together with an extremely low level noise floor of -145dB @ 2V RMS, indicates how this fine detail retrieval is made possible.

Amethyst By Metrum Acoustics can be used as a stand-alone DAC. Fixed level standard Redbook 2V output is available – direct from the new DAC TWO modules – no output stage is necessary to hinder/cloud signal information. The connection goes straight to the Analogue outputs – to feed Amplification.

Be wary of any device that outputs more than the Industry Standard 2V output. This will falsify comparison … so begs the question – why do some manufacturers do this ?

Only one answer !

Headphone volume control is designed to power lower impedance models down to 16 Ohms. 4 Volts is available on loads between 16 and infinity … so power is constant regardless of the load.

When Phones are connected, volume control becomes active and when disconnected, the Analogue outputs become active with volume control muted.

With the Analogue output circuits in play, all power is diverted to DAC performance.



Srajan Ebaen has put Amethyst through its paces. Thoroughly out of context … HiFiMan’s US$6K Susvara Headphones are also under Review. It would seem Amethyst is capable, in powering the most difficult to drive Phones he has ever come across.

“With Metrum’s paralleled FPGA-corrected R2R ladders coupling to the outputs through just an impedance-conversion buffer, plugging in Susvara approached that futuristic notion of direct neural wiring to the cortex; in the here now. The illusion of nothing between my ears and the music was unusually strong. “I truly felt inside the music; a very different sensation from speaker listening or even good regular headphones”.



Working principle

Non oversampling dac


Forward corrected


1x DAC TWO modules per channel


30 VA toroidal transformers

Mains voltage

110/115V AC 220/230V AC 60/50Hz


1x optical, 2x coaxial and USB


RCA : 2 Volts RMS


Volume controlled headphone connection


Max load 16 Ohms

Frequency response

1Hz – 20 khz -1dB. 44.1 kHz sampling


1Hz – 65 kHz -1dB .192 kHz sampling


0.006 % THD

Noise floor

-145 dB related to 2 Volt RMS

Output impedance

RCA 100 Ohm. Headphone output 3 Ohms

Sampling rate

Optical 44.1 – 96 kHz sampling rate


Coax 44.1 -192 kHz, USB 44.1 kHz -384 kHz


19 x 6 x 25 cm


2.5 kg.