Nagra Tube DAC vs Classic DAC review June 2019
We were excited to receive our first samples of Nagra’s brand new Tube DAC – one of the first in existence anywhere.
To call the Tube DAC just a ‘DAC’ is doing it something of a disservice: it’s a two-box solution comprising a DAC with variable output and a standalone power supply, the latter featuring three stabilised 12 volt DC outputs – two of which are used to drive the Tube DAC’s digital and analogue circuits separately, and the third output may be used to power another item in an all-Nagra system.
We promptly wired up a Nagra Classic system with nicely matched Siltech cables throughout. The system comprised a standard mains-powered Classic DAC playing into a Classic Pre pre-amp and a Classic Amp stereo power amplifier all sited on NAGRA’s beautifully finished VF-S vibration absorbing isolation platforms, and in this case driving a pair of the astounding KEF Blade II loudspeakers. We arranged connections so that it was quick and easy to swap the balanced interconnect leads between the two DACs and also swap the USB digital lead from our Aurender source between the two units.
We ensured the volume levels set on the pre-amp were identical and the output of the Tube DAC was at fixed line-level and settled down to some serious listening.
Beginning with the Classic DAC, and playing Alison Balsom’s Music for Trumpet and Organ (16 bit 44.1kHz FLAC files) we were treated to a beautifully open and spacious sound from the Blade II’s (these speakers have the most amazing stereo imagery!) and the classic open and naturally realistic sound which we expect from Nagra.
However, once we had switched over to the Tube DAC, the sound stage became almost holographic and the sound even smoother, richer, cleaner and clearer! Alison’s trumpet playing seemed even more expressive than with the Classic DAC and the ambient decay from the instrument in the acoustics even clearer. The sounds from the pipe organ were not merely clearer, but also seemed to float in the atmosphere. It was certainly not a subtle improvement.
We repeated the same comparisons with a Naxos recording of Khachturian’s Spartacus Suites 1-3 (St Petersberg State Symphony Orchestra Conductor Andre Anichanov), with the same kinds of differences. Moving to different genres: Jonny Cash’s Folsom Prison recording Long black Veil revealed even more expression in Jonny’s deep gravelly voice with the Tube DAC, while Nirvana’s Heart Shaped Box sounded better resolved – not that every Nagra owner would necessarily play Nirvana on their system, (the Nagra ‘sound’ is particularly well suited to naturally recorded music and especially classical), but it’s been known!
We wondered how much the separate power supplies contributed to the lift in performance of the Tube DAC, so we hooked up one of the 12V lines from the Tube DAC’s power supply to the Classic DC and disconnected the latter from the mains, so that it relied solely on the external stabilised DC supply. Not surprisingly, the sound of the Classic DAC was elevated above that of the mains powered unit, becoming a bit smoother and more open, but it did not reach the heady heights of the full-blown Tube DAC.
Mind, you, the Tube DAC really should perform to a higher standard than the Classic DAC considering its heady price tag, and although the ‘law of diminishing returns’ is very much evident here, the sonic and musical improvements the two box offering delivers go some way towards justifying it in this case.
Links below for further information: