Döhmann Helix Two Mk3 Turntable Lab Report

Lab Report

While Döhmann's Helix Two Mk3 is accompanied by an 'external advanced DC power supply', the decoupled Swiss-made motor is an AC-synchronous type whose absolute speed may be adjusted in very fine steps (±0.1rpm at the spindle, or ±0.01rpm at the platter) so that perfect pitch may be achieved [see Graph 1, below]. The deck's peak-wtd wow is an impressively low 0.02% – so it will sound pitch stable – but the peak-wtd flutter is higher at 0.08% principally due to a diffuse cluster of sidebands at ±10Hz, clearly revealed on the W&F spectrum. Such higher-rate sidebands are not uncommon [HFN Jan '22, Mar '22, Feb '23] and are typically linked to bearing/suspension modes or in this case, perhaps, the 'high torque adjustable drive (HTAD) as the same ~10Hz and lower amplitude ~20Hz modes are visible on the unwtd rumble and noise spectrum (not shown here) at –56dB re. 1kHz/5cm/sec.

The DIN-B wtd through-bearing rumble is excellent, however, at –70.5dB, falling only slightly to –70dB through-the-groove where the effectiveness of the RSA-equipped record clamp proves itself to the tune of ~0.4dB. It must be said that none of these standard measurements attempts to quantify the efficacy of the integrated Minus K vibration isolation system. Finally, a brief word about the partnering Reed 5A 'tangential-tracking'/double-pivot tonearm. Our sample, equipped with a Wenge wood arm wand, showed a low-Q beam resonance below 100Hz with associated modes at 140Hz and 225Hz plus a higher-Q bending/harmonic at 280Hz [see CSD waterfall, Graph 2, below]. Despite its evident complexity, the arm's resonant behaviour is remarkably benign. PM


Wow and flutter re. 3150Hz tone at 5cm/sec (plotted ±150Hz, 5Hz per minor division). The fine speed adjustment allows for precise tuning


Cumulative resonant decay spectrum for Reed 5A tonearm, illustrating various structural support and tube vibration modes (100Hz-10kHz over 40msec)

Turntable speed error at 33.33rpm 33.33rpm (–0.01%)
Time to audible stabilisation 4-5sec
Peak Wow/Flutter 0.02% / 0.08%
Rumble (silent groove, DIN B wtd) –69.5dB (–69.9dB with clamp)
Rumble (through bearing, DIN B wtd) –70.5dB
Hum & Noise (unwtd, rel. to 5cm/sec) –55.8dB
Power Consumption 14W
Dimensions (WHD) / Weight 480x200x400mm / 38kg
Price £46,000-£51,500 (depending on finish)

Döhmann Audio Pty Ltd
Victoria, Australia
Supplied by: Absolute Sounds Ltd
0208 971 3909