Phono Preamplifier Soulution 550 Phono Stage

Soulution 550 Phono – dual-mono phono stage with up to 80 dB of gain and 1 MHz bandwidth

The Soulution 550 Phono is a phono stage with RIAA equalisation, designed for both MM and MC cartridges, including systems with very low output voltage. Delivering up to 80 dB of gain (a factor of 10,000) while preserving linearity and phase accuracy is one of the most demanding tasks in analogue engineering – the 550 Phono solves it through a combination of an ultra-wide bandwidth (internally 1 MHz/–3 dB), minimal distortion (THD+N < 0.002 % over 20 Hz – 20 kHz) and a signal-to-noise ratio of 100 dB.

Structurally it is a single-ended dual-mono design with separate power supplies for the left and right channels, which minimises crosstalk between channels (60 dB at 1 kHz). Both RCA inputs can be configured independently for MM or MC cartridges, with loading impedance selectable from the front panel or the remote control – 10 Ω to 1000 Ω for MC, 1000 Ω to 47 kΩ and 0 – 200 pF for MM. A switchable rumble filter < 20 Hz limits low-frequency cone excursions caused by warped records.

The output section uses power supplies and output stages identical to those of the Soulution 520 preamplifier. They are optimised for speed and precision, offer an output impedance of 10 Ω both balanced and single-ended, and can effortlessly drive virtually any interconnect cable. One balanced XLR and one single-ended RCA output are available, with a maximum output voltage of 11 VRMS (XLR) or 5.5 VRMS (RCA), at a current limit of 0.2 A.

The result of these solutions is audible straight away during playback: low noise and distortion at extremely small input levels preserve the tone colour of instruments, microdynamics and the intelligibility of quieter passages, while the separate channel power supplies contribute to stable imaging within the stereo stage. Weighing approximately 20 kg and measuring 442 × 143 × 448 mm, the unit also features LINK 12 V control for remote power-up within a system.

Key features

• Gain: Up to +66 dB (MC, XLR) and +55 dB (MM, XLR)
• Design: Dual-mono with separate power supplies per channel
• Inputs: 2 × RCA, configurable MM/MC with selectable loading
• Bandwidth and distortion: 0 – 1 MHz (–3 dB), THD+N < 0.002 %
• Outputs: XLR and RCA with 10 Ω impedance, rumble filter < 20 Hz