Turntables, Arms & Cartridges

As discussed the L/R signals from Soundsmith's pick-up are derived from variations in the impedance of its internal strain gauges, so the ~500mV output refers to its partnering SG-230 bridge/preamp. The 1.2dB channel imbalance remains a function of the cartridge as does distortion – the 'equalised' lateral trace (L+R, –8dB re. 5cm/sec) comparable to that from a good quality MC, hovering between 0.35-1% from 20Hz-3kHz [black trace, Graph 2] despite proving just a little higher via the left channel. Vertical [L-R] distortion [red trace, Graph 2] is also slightly higher than typical at ~3-4% via both channels over the same 20Hz-3kHz bandwidth, this tempering peripheral rather the centre-focused detail. THD is also influenced by tracking performance, but despite its low 10cu compliance and undamped +25dB fundamental resonance, the low moving mass of the SGS-5's ruby cantilever, line contact diamond and fine piezoresistive strips secures its hold onto grooves up to a modulation of +15dB (re. 315Hz/5cm/sec, <1% THD). The high 2.3g downforce assists...

The SGS-5/SG-230's frequency response, and its equalisation of the RIAA encode characteristic, is achieved partly by an active LF boost while relying on the natural mechanical roll-off of the pick-up to counter the ~1st-order emphasis applied to records above 2.1kHz (75µsec). Nevertheless the reinforced upper bass/lower mid, depressed presence and peaked high treble [Graph 1, below] suggests this is only partially successful. Once again, lateral (L+R) cuts [black trace] are captured more convincingly than vertical (L-R) modulations but – crucially – note the inherent 'smoothness' of the responses and freedom from HF resonances seen in all my measurements of traditional MM/MC pick-ups. PM