Phonostages — Genuin Audio pearl

The pearl is a phono stage from Genuin Audio, the German analogue and loudspeaker company, designed by Walter Fuchs of Bochum, who adjusts the gain and frequency response linearity of each unit by hand at the end of production. It accepts two cartridges at once, a moving-coil or high-output moving-coil on a balanced XLR input and a moving-magnet or moving-iron on an RCA input, and it has balanced XLR outputs only. A further-optimised version can be built into Genuin's drive turntable.

Key specs that matter

The MC section offers input impedance from 125 ohm to 2 kOhm, 2 x 470 pF, gain of 20, 22, 24, 26 or 28 dB, common-mode rejection above 90 dB from 20 Hz to 20 kHz and output impedance of 2 x 47 ohm. The MM and MI section offers capacitance from 47 to 285 pF in five steps and gain of 37, 40, 42, 44 or 46 dB, and its S/N exceeds 80 dB unweighted. RIAA deviation from 10 Hz to 100 kHz is within ±0.3 dB and typically below 0.1 dB, both per channel and between channels. Maximum output exceeds 19 V balanced. THD+N and intermodulation distortion are each below 0.001%. A switchable subsonic filter works at 15.9 Hz with 18 dB per octave. The phono stage measures 205 x 63 x 262 mm and weighs 2.4 kg, and the external power supply measures 165 x 70 x 315 mm and weighs 4.1 kg.

Engineering and use context

Fuchs separated the two channels into independent circuits and runs every amplifier stage in Class A. Switching is handled by sealed relays with gold, silver and palladium crossbar contacts. The RIAA equalisation is split into two stages, one active for stability against overload and one passive, using paired 1% MKP capacitors, and it follows the RIAA curve without the Neumann time constant. The op-amps have distortion below 0.0001%, and resistors in the equalisation and output stages are 0.1% types. Settings are made with two rows of DIP switches underneath. The external supply uses a 250 VA toroidal transformer, a mains filter with DC suppression and stabilisation down to less than 25 µV of residual noise, with more than 40,000 µF of capacitance, and the phono unit itself holds more than 80,000 µF. The slide-in case combines a steel inner shell and an aluminium outer shell, with damped boards and rubber-ring feet.

Pairing

The balanced XLR outputs connect to preamplifiers with XLR inputs. Genuin's sting moving-coil cartridge, with its recommended 500 to 1,000 ohm load, falls within the pearl's MC range, and the drive turntable can hold an integrated version with additional Decca and Columbia curves.

Alternatives

At present Genuin Audio makes no other standalone phono stage, since the pearl is its only phono preamplifier.