Outboard DACs

In practice, the beating (digital) heart of The Raven is rather closer to that of the H400 amplifier [HFN Oct ’24] – itself based on the H600 [HFN Oct ’23] – than the Viking CD player [HFN Sep ’23 and [see boxout] with its AK4493SEQ converter. The H400 uses an ES9038Q2M DAC while the D50 Raven employs the newer ES9039Q2M solution together with Hegel’s choice of minimum phase filter. The filter coefficients are slightly ‘tweaked’ here because the stopband rejection has shifted from 83dB (H400) to a slightly reduced 75dB while the responses are extraordinarily flat and extended [see Graph 2, below]. Via the fixed (2.59V) line out, from a low and consistent 24ohm source impedance, the responses reach out to ±0.01dB/20kHz, –0.25dB/45kHz and –0.31dB/90kHz with 48kHz, 96kHz and 192kHz media, respectively. The A-wtd S/N ratio is also a very respectable 111.7dB while low-level linearity is true to ±0.6dB over a full 110dB dynamic range (24-bit data).

Distortion is also lower in the D50 than with any previous Hegel digital player/DAC, and significantly lower than the product’s basic 0.0002% specification. With peak (0dBFs) digital inputs, THD holds to 0.00005-0.0001% (re. 20Hz-20kHz) and falls to a minimum of 0.00002-0.00006% over the top 20dB of its dynamic range [see Graph 2]. While this may be of technical interest only, it speaks volumes about the overall attention to detail in Bent Holter’s implementation of ESS’s latest DAC chip. In similar fashion, correlated jitter is suppressed to <9psec across all sample rates while uncorrelated jitter/phase noise is all but eliminated. This, and the 120dB midband stereo separation, bode well for super-sharp stereo soundstages! PM