AVID Reference Ruby Cartridge Lab Report

Lab Report

While some design and performance features – including the X-shaped coils, superb tracking performance and extended but 'bright' treble response – all have a Lyra-esque quality [HFN May '13], AVID's flagship MC is arguably closer to Sumiko's Starling [HFN Mar '20] in respect of its arm/phono preamp matching. In order to maintain a low moving mass, the long ruby cantilever carries fewer coil turns, and thus has a lower internal resistance and output, the latter precisely matching AVID's 0.32mV spec. (re. 1kHz/5cm/sec). The channel balance is tight at 0.3dB, stereo separation held to between 23-28dB (20Hz-20kHz) and, while the 'micro-ridge' stylus is well polished and precisely mounted on its ruby cantilever, VTA looks closer to 30o than the usual 20-24o. Compliance is low at 9cu and this, combined with the 9g bodyweight, renders it very compatible with today's higher (11-16g) effective mass tonearms.

Despite its relatively 'stiff' compliance, the Ruby is a very secure tracker at its recommended 2.0g, achieving ~75µm via the left/right channels, respectively, and keeping hold of a high +15dB groove modulation (re. 315Hz/5cm/sec) at ~0.4% THD. There is some slight asymmetry in the generator here, the right channel having a hotter presence leading to a kick above 8kHz that reaches +6dB/20kHz on lateral (L+R) cuts and +3dB/20kHz with vertical (L-R) traces [solid traces, Graph 1, below]. The left channel [dashed traces] has a milder +2dB/20kHz (lateral) and +1.5dB/20kHz (vertical) response, but distortion is uniformly high on both channels – up to 20%/15kHz (–8dB re. 5cm/sec) – not because the Reference Ruby is especially non-linear, but because it has an uncommonly extended HF response. PM


Freq. resp. curves (–8dB re. 5cm/sec) lateral (L+R, black) vs. vertical (L–R, red). L channel dashed


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

Generator type/weight Moving-coil / 9.1g
Recommended tracking force 18-22mN (20mN)
Sensitivity/balance (re. 5cm/sec) 318µV / 0.3dB
Compliance (vertical/lateral) 9cu / 8.5cu
Vertical tracking angle 30 degrees
L/R Tracking ability 75μm / 75μm
L/R Distortion (–8dB, 20Hz-20kHz) 0.47–20% / 0.38–18%
L/R Frequency resp. (20Hz-20kHz) –0.3 to +2.7dB / –0.4 to +6.2dB
Stereo separation (1kHz / 20kHz) 28dB / 23dB
Price £6000
AVID Hi-Fi Ltd
Kimbolton, Cambs
Supplied by: Avid Hi-Fi Ltd
01480 869900