Outboard DACs

Tested via its balanced XLRs in variable 'Low Output' mode, and with the volume set to '100', the Premier delivers a maximum 1.675V from a moderate 36ohm source impedance. Although volume extends to '106', digital clipping occurs at '101' with a full scale 0dBFs input, so I would recommend '100' as the maximum setting. While the output is 1.5dB below the de facto 2V standard for digital sources, its A-wtd S/N ratio is still a very generous at 108dB and low-level linearity good to within ±0.2dB over a full 100dB dynamic range. Distortion is low enough, but not vanishingly so, at 0.0016-0.014% (0dBFs, 20Hz-20kHz) with a minimum of 0.0015-0.006% occurring at –10dBFs. However, it's only our distortion versus digital level measurements [see Graph 1] that reveal the unique behaviour of the Prime DAC's R-2R network with its characteristic 'ripples' between –18dBFs and –32dBFs. We saw something very similar with MSB's Power DAC [HFN Apr '08] – it's certainly a 'fingerprint', albeit of uncertain subjective impact!

One feature that does make a huge difference, however, is the Premier's world-class jitter rejection [see Graph 2]. Not only is any correlated jitter suppressed to <2psec (all sample rates, all inputs) but the exquisite sharpness of the test signal – free of any spectral leakage – proves the absence of any decorrelated (noise-like) jitter. I have not seen this level of performance even with the best implementations of the ESS Sabre DACs. This, in part, is a function of MSB's long linear phase digital filter which also delivers a full >130dB stopband rejection and sets the ultimate freq. response of the various incoming sample rates. Files at 44.1/48kHz extend to –0.06dB/20kHz, 96kHz files reach –1dB/27kHz and 192kHz inputs roll-off at –1dB/30kHz. PM