MoFi StudioDeck+ Turntable Package Lab Report

Lab Report

By combining the same 300rpm AC synchronous motor and hardened steel inverted bearing (albeit with a Teflon rather than sapphire thrust pad) with a lighter Delrin platter (1.8kg vs. 3.1kg), the performance of the StudioDeck inevitably differs from that of the UltraDeck [HFN Jul '19]. Start-up time is not substantially reduced as both decks exhibit some belt slippage for the first half-revolution, but the absolute speed error is somewhat higher at +0.33% in the StudioDeck. This is reflected in the right-hand shift of the main signal peak [Graph 1] but is unlikely to cause an audible pitch change. Moreover, peak wow is reduced in the StudioDeck from 0.07% to 0.05% thanks to a suppression of the deck's ±5Hz sidebands. Higher-rate flutter is unchanged at 0.04% and essentially uncorrelated (noise-like). Through-bearing rumble is also unchanged at –67.7dB (DIN-B wtd, re. 5cm/sec) but through-groove rumble was 3-4dB higher in the StudioDeck at –67.2dB, possibly as the lighter platter offers slightly less overall damping.

MoFi's 10in alloy tonearm is a true heavyweight with an effective mass a little over 30g, so it's fortunate the supplied StudioTracker MM weighs only 6.4g. This high mass arm suits lower compliance pick-ups but also contributes to some bold resonances seen on the CSD waterfall plot [Graph 2, below] – the latter unaffected by the change in internal wiring. The main bending mode occurs at 145Hz and the secondary modes at 440Hz, 710Hz and 980Hz. Some additional damping would benefit the arm's performance although its proven gimbal/ballrace bearings are of superb quality at the price – absolutely free of any play while offering a very low <10mg friction. PM


Wow and flutter re. 3150Hz tone at 5cm/sec (plotted ±150Hz, 5Hz per minor division)


Cumulative tonearm resonant decay spectrum, illustrating various bearing, pillar and 'tube' vibration modes spanning 100Hz-10kHz over 40msec

Turntable speed error at 33.33rpm 33.44rpm (+0.33%)
Time to audible stabilisation 4sec
Peak Wow/Flutter 0.05% / 0.04%
Rumble (silent groove, DIN B wtd) –67.2dB
Rumble (through bearing, DIN B wtd) –67.7dB
Hum & Noise (unwtd, rel. to 5cm/sec) –58.0dB
Power Consumption 5W (<1W idle)
Dimensions (WHD) / Weight 500x137x362mm / 8.7kg
Price (with arm/cartridge) £1349
MoFi Electronics
Chicago, USA
Supplied by: Karma-AV Ltd, York
01423 358846