Pro-Ject Debut PRO S Turntable Package Lab Report

Lab Report

Like the original Debut PRO [HFN Sep '21] the new 'S' shares the same PSU and decoupled AC motor as the earlier X1 [HFN Aug '19] and X2 [HFN Nov '19] models, although the TPE-damped alloy platter now sits on a 'diamond-cut' alloy sub-platter. Once again, the deck is supplied with glued round-section (78rpm) and continuous flat-section (33.3/45rpm) rubber belts, the latter essential to realise the low 0.02% peak-wtd wow [see Graph 1] and very minor –0.06% absolute speed error. We've seen the ±82Hz/0.04% flutter before on the Debut PRO and X2 turntables, this component also popping up on the unwtd rumble spectrum. However, the new sub-platter brings some 2dB less through-bearing rumble on the PRO S at –65.9dB (DIN-B wtd), improving to a very fine –70.5dB when measured through-the-groove. This performance deteriorates very slightly to –68.5dB once Pro-Ject's puck/record weight adds a little extra load to the bearing and 'couples' the LP more effectively onto the platter.

The new S-shaped tonearm features a four-point cardan bearing, a decoupled counterweight system and one-piece alloy tube with SME-style detachable headshell/cartridge mount. This also reduces its effective mass to 8g – ideal for high compliance MMs. S-shaped tubes typically have more complex resonances than straight beams, and so it is here with the rather 'lively' series of modes beginning with a main flex at 105Hz, and harmonics at 200Hz/280Hz, followed by a cluster of other bending/torsional modes from 440Hz-760Hz [see CSD waterfall, below]. The sharp but quickly dissipated break at 960Hz looks to be associated with the long, end-of-arm fingerlift. Otherwise the arm bearings are impressively free of play and friction is just ~10mg. PM


Wow and flutter re. 3150Hz tone at 5cm/sec using Pro-Ject's flat belt (plotted ±150Hz)


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

Turntable speed error at 33.33rpm 33.31rpm (–0.06%)
Time to audible stabilisation 3-4sec
Peak Wow/Flutter (Peak wtd) 0.02% / 0.04%
Rumble (silent groove, DIN B wtd) –70.5dB (–68.5dB with weight)
Rumble (through bearing, DIN B wtd) –65.9dB
Hum & Noise (unwtd, rel. to 5cm/sec) –57.9dB
Power Consumption 5-8W (1W standby)
Dimensions (WHD, with lid) / Weight 462x145x345mm / 7kg
Price £799 (inc. arm and cartridge)
Pro-Ject Audio Systems
Supplied by: Henley Audio Ltd, UK
01235 511166