Фонокорректоры — Exposure VXN Phono Amplifier

The VXN Phono Amplifier is an MM and MC phono stage from the VXN Series of Exposure, the British electronics company from Lancing, West Sussex. The series also includes two-way and three-way active crossovers and the VXN PSU power supply. The phono stage has no mains inlet of its own and must be powered by the VXN PSU, priced at GBP 1,010, while the phono stage costs GBP 1,790. Its circuit evolved from the XM3 phono stage.

Key specs that matter

Nominal output is 500 mV, and maximum output is 7.8 V at 1 kHz, with an output impedance of 50 ohm. THD is below 0.005% at 1 kHz. Frequency response is 30 Hz to 20 kHz ±0.25 dB, with a roll-off below 30 Hz. The moving-magnet input produces 500 mV from 5 mV, equal to 40 dB, and its S/N exceeds 82 dB A-weighted. The moving-coil input produces 500 mV from 500 µV, equal to 60 dB, with signal to noise ratio above 72 dB. MM loading is fixed at 47 kOhm and 220 pF, and MC loading can be set from 32 to 1,000 ohm in twelve steps through rear DIP switches. Outputs are single-ended RCA only. Power consumption is below 10 W. The phono stage measures 218 x 90 x 348 mm and weighs 2 kg, in black, with a three-year guarantee.

Engineering and use context

Exposure builds the whole signal path from discrete transistors, with no integrated circuits. A discrete FET input stage leads the circuit, and the MC stage places transistors in parallel to lower noise. Multi-stage low-noise regulators follow the external supply, and cascode circuitry improves the rejection of power supply noise. The RIAA stages use polypropylene capacitors, and only polystyrene and polypropylene capacitors are used in the audio path. Toshiba bipolar transistors form the output stage. Moving the mains transformer into the VXN PSU keeps it outside the phono chassis. The PSU has two 30 V outputs and one 12 V output, and twin power inputs on the phono stage allow a second PSU to supply the left and right channels separately. The MM and MC selector is on the front panel. The deliberate bass roll-off limits rumble and warp signals. The case is aluminium with an extruded front.

Pairing

Its nominal output suits any line input, including Exposure's 3510 and 5510 amplifiers, and the MC loading range covers most moving-coil cartridges.

Alternatives

The Exposure XM3 Phono Amplifier is the compact XM-series phono stage on which the VXN circuit is based.