Artemis is the version of the Reference Tube DAC built on the Burr-Brown PCM63, a 20-bit multibit chip from around 1990. Dmitriy Gubchenko voices it as large-scale and weighty.
The Burr-Brown PCM63
The PCM63 is a 20-bit mono converter with a resistor ladder on the chip, trimmed by laser at the factory. Its Colinear design arranges two complementary ladders so that the major-carry error at the zero crossing, the point every quiet signal passes through, is kept small.
Like the other multibit chips of the five it delivers a current rather than a voltage, and a stereo converter uses two, one per channel. Our notes on the PCM63 datasheet go further into the current output.
Grades and old stock
Burr-Brown graded the PCM63 by linearity, the K grade being the most closely selected. Production ended long ago, so every PCM63 in use today is old stock. Remarked chips circulate, and each part is checked before it is fitted.
Without oversampling
In Artemis the PCM63 converts the 16-bit / 44.1 kHz signal from coaxial S/PDIF as it arrives, without an interpolation filter or upsampling, so its impulse response shows no pre-ringing. The treble rolls off gently, by about 3 dB at 20 kHz, and image frequencies above 22.05 kHz reach the output stage; our guide to NOS multibit DACs explains why.
Artemis among the five
The PCM63 is commonly described as large-scale and weighty, and Artemis is the large-scale voice of the five. Katerina on its successor, the PCM1704, has strong bass, detail and attack; Persephone on the Philips TDA1541 is fast and articulate. All five share the same chassis, input, output options and price. The stock output stage is solid-state; a tube stage on 6Zh4, EF14, EL8, AL4 or ML6 with a 5Ts4M rectifier is optional. Each unit ships with its own measurement report.