For PCM digital-to-analog conversion, the choice of an R-2R design fits perfectly with Denafrips’ philosophy of emphasizing sound quality over measurements. According to Mr. Zhao, total harmonic distortion at levels lower than 0.003% has almost no perceptible effect; indeed, excessive pursuit of low distortion levels per se may have an adverse effect on sound quality. Therefore, his first priority is to minimize digital-conversion artifacts without exceeding this distortion guideline. The end result sought is smooth, analog-like sound quality.
The R-2R resistor ladders are discrete and contain about five hundred 0.005% precision resistors per channel for 26-bit resolution. The Terminator is capable of reproducing PCM up to 1.536MHz and DSD up to 45.2MHz (DSD1024) in native mode. The PCM digital-to-analog conversion scheme is based on sign-magnitude technology, which was introduced in the early 1990s by Burr-Brown in chip form. Such designs have also been referred to as “push-pull,” since there are two identical DAC sections per channel, with negative and positive polarity digital words being handled by separate sections. The net effect is to add and subtract voltage from the resistor ladder starting from the zero-crossing point, thereby resulting in smaller steps as bit switches are turned on and off. On average, the smaller step sizes result in less transient-induced noise and greater precision at low-levels. Execution is critical, so no expense was spared in the Terminator, as in deploying Crystek FEMTO clock oscillators designed specifically for high-resolution audio applications to ensure that the DAC clock is independent of the input signal.
Specs & Pricing
Type: Balanced 26-bit R-2R + 6-bit DSD
PCM: 24-bit/44.1, 48, 88.2, 96, 176.4, 192kHz on all inputs; 1536kHz on USB and I²S inputs
DSD: DSD64-DoP on all inputs; DSD1024 on USB and I²S inputs
Digital inputs: 75-ohm coax and BNC, TosLink, AES/EBU XLR, USB, I²S inputs (x3)
Analog output: Single-ended RCA at 2.3Vrms/625 ohms; balanced XLR at 4.6Vrms/1250 ohms
Frequency response: 20Hz–40kHz (-0.2dB)
S/N ratio: 124dB
Dynamic range: >132dB
Stereo crosstalk: -110dB
Dimensions: 43 x 10.5 x 38cm
Weight: 19.0 kg