DS Audio Grand Master EX Cartridge Lab Report

Lab Report

Bearing in mind that this 'Extreme' version of the Grand Master flagship [HFN Feb '21] is distinguished only by its one-piece diamond stylus/cantilever then the measurable differences depend as much on the sample-to-sample production variation of the shared photo-electric mechanism. In practice the precise matching of its 22° VTA and 11/15cu compliance is remarkable in itself, the latter playing a significant role in determining the tracking prowess of these pick-ups. Both Grand Masters will hold onto the maximum +18dB test track (re. 0dB at 315Hz/5cm/sec) at a 2.0g downforce, albeit at ~1.5% THD.

Once again, the 2.05V output (re. 1kHz/5cm/sec) is a function of the GM equaliser as are the six 'bass contours', three rolling off from a notional 50Hz and three from a lower 30Hz. Output 1 provides a +3.6dB/+1.9dB boost at 20Hz in 30Hz/50Hz settings [black/grey traces, Graph 1], while Output 3/50Hz (–4.4dB/20Hz) is arguably the 'safest' with big, reflex-loaded speakers. Channel balance, incidentally, was a far tighter 0.1dB with our sample of the EX. Otherwise the boosted and extended HF response of +5.5dB/20kHz [–8dB re. 5cm/sec; dashed HF trace Graph 1] marks out the GM and GM EX as the most advanced in DS Audio's stable, but note how the EX's response is visibly 'smoother' than the GM's. The extended bandwidth is also reflected in the 4-5% stereo THD peak being pushed out from ~7kHz to 9kHz here [see Graph 2, below] while the excellent lateral/vertical symmetry is clear from both the response and THD plots [solid black and red traces/infills]. PM


Freq. resp. (–8dB re. 5cm/sec) lateral (L+R, black) vs. vertical (L–R, red) vs. stereo (dashed). Bass only: Output 1/30Hz, solid; 2, dashed; 3, dotted; Output 1/50Hz, grey solid; 2, dotted; 3 dashed)


Lateral (L+R, black), vertical (L–R, red), stereo (dotted) tracing and generator distortion (2nd-4th harms) vs. freq. from 20Hz-20kHz (–8dB re. 5cm/sec)

Generator type/weight Photo-optical / 7.7g
Recommended tracking force 20-22mN (21mN)
Sensitivity/balance (re. 5cm/sec) 2050mV / 0.1dB (from Eq unit)
Compliance (vertical/lateral) 11cu / 15cu
Vertical tracking angle 22 degrees
L/R Tracking ability 80μm / 65μm
L/R Distortion (–8dB, 20Hz-20kHz) 1.2-6.7% / 0.3-5.8%
L/R Frequency resp. (20Hz-20kHz) +3.6 to –1.1dB / +3.6 to +2.1dB
Stereo separation (1kHz / 20kHz) 34dB / 25dB
Prices £18,995/£42,200 (cartridge/PSU & equaliser)

Digital Stream Corporation
Kanagawa, Japan
Supplied by: Soundfowndations Ltd, Berks
0118 9814238