Фонокорректоры — Nagra Compact Phono

Nagra's Compact Phono is a phono stage built only for moving-coil cartridges by the Swiss firm that began in 1951 and is run today as Audio Technology Switzerland SA. It belongs to Nagra's Compact range and shares its chassis with the Nagra Streamer, while the circuit is derived from the microphone preamplifiers of the Nagra IV-S reel-to-reel recorder. Nagra traces the line back to its original PL-P phono stage and describes the Compact as carrying most of the quality of its bigger predecessors into a small case. The US price at launch was USD 4,950.

Key specs that matter

A hand-wound Nagra transformer with 10 dB of gain forms the input stage, and a switch selects 47.5 dB or 62 dB overall. Frequency response is 20 Hz to 50 kHz within 1 dB of the RIAA curve. Noise sits more than 80 dB down at 100 Hz on low gain and better than 72 dB on high gain, crosstalk exceeds 85 dB and 73 dB for the two settings, and THD plus noise stays below 0.1% at 1 kHz on a laboratory supply. Output impedance is under 10 ohm on low gain and under 25 ohm on high. Connections are RCA in and out plus a ground terminal. Power comes from 12 V DC, consumption is 0.5 W, and the case measures 185 x 166 x 41 mm and weighs 1.9 kg.

Engineering and use context

The step-up transformer is wound at the Nagra factory in Switzerland and is the same part used in the valve VPS phono stage. Behind it sits an all-discrete class A transistor circuit with a dual-mono layout, built with military grade transistors selected individually. An internal power stage uses high-rejection regulators and two-stage filtering. Cartridge loading is set by a plug-in mini-XLR resistor - the unit ships with 100 ohm, a value Nagra considers suitable for most cartridges, and other values come in a kit. The case is machined out of one aluminium billet, and its bottom plate is damped with 3M damping tape against internal vibration. Nagra's Compact VFS base was developed for the range as an optional support. The unit is rated for indoor use between 15 and 35 degrees C and is covered by a three-year warranty.

Pairing

Nagra matches the gain to cartridge output - high gain for cartridges below 0.7 mV, low gain above 0.7 mV. In place of the supplied adapter, owners can use a Nagra ACPS III, MPS or Classic PSU through an optional Lemo-to-DC cable, with the Classic PSU named as the best option. The RCA outputs connect to any line-level preamplifier.

Alternatives

Within Nagra's current catalogue, the HD Phono is another phono stage option from the Swiss maker.