Thorens TD 204 Turntable Package Phono Fundamentals

Phono Fundamentals

To all intents and purposes, the TD 204's inbuilt phono stage is the same as that we saw in Thorens' TD 202 'USB turntable' solution [HFN Jan '22]. This is very much a 'get you on the road' RIAA preamp with its limited +34.7dB gain (+45dB would be more typical) offering a 190mV output (re. 3.5mV/5cm/sec) that tops out at 500mV for <1% THD. Neither is the input overload particularly generous at just 9mV – that's just +8dB headroom over the nominal 3.5mV of the supplied AT-95E pick-up. (MM headroom is ideally ~100mV.) However, while distortion reaches ~2% THD for +18dB headroom, equivalent to the most extreme groove modulations likely to be encountered, these sorts of figures are still lower than would be produced by the cartridge itself...


Otherwise, distortion from the phono stage falls from 0.12%/20Hz to ~0.035%/1kHz at 200mV output [red trace, inset Graph] while the limited gain fortuitously serves up a low –88.8dBV residual noise and wide 82dB A-wtd S/N ratio – this being 'quieter' than a silent LP groove. Thorens has opted for a steep 'rumble/feedback' filter in its phono response [black trace, inset Graph] which is already –2.1dB down at 20Hz before falling to –6dB/9Hz. The treble is flat to within ±0.1dB up to 30kHz, rising thereafter to +2.5dB/100kHz. PM

Thorens GmbH
Bergisch Gladbach, Germany
Supplied by: Signature Audio Systems
07738 007776