Фонокорректоры — Vincent PHO-701

The PHO-701 is a two-box valve hybrid phono preamplifier from Vincent, developed from the PHO-700. It adds two things to its predecessor - DIP switches for setting cartridge load and capacitance, and a USB output for digitising records. The power supply sits in its own case, the same unit Vincent uses for its PHO-8 phono stage, and connects to the audio chassis through a nine-pin DIN cable.

Key specs that matter

A single stereo RCA input can be switched between moving magnet and low output moving coil operation. Gain is 40 dB for MM and 60 dB for MC, with input sensitivity figures of 58 mV and 6.8 mV respectively. The MM input presents 47 kohm with capacitance adjustable from 15 to 350 pF, while the MC input is adjustable from 99 to 1,000 ohm with a fixed 15 pF. Signal to noise ratio is above 81 dB for MM and above 69 dB for MC. Frequency response runs from 10 Hz to 20 kHz, harmonic distortion stays below 0.05 % between 20 Hz and 20 kHz, and output impedance is 250 ohm. Each of the two cases measures 130 x 95 x 225 mm, the unit weighs 2.2 kg, and maximum power consumption is 15 W.

Engineering and use context

A single 12AU7 double triode, visible through a window in the front panel, works in the signal path alongside solid-state circuitry. Parts from Nichicon, Wima and other suppliers are used to lower noise. Placing transformer and regulation in a separate box from the gain stages keeps hum and ripple from the mains out of the sensitive phono circuit, with the voltage regulated and filtered before it reaches the audio board. The DIP switches are located on the underside of the audio chassis, and the owner sets load and capacitance to the values listed in the cartridge user guide. For archiving, a Cirrus Logic CS5340 converter samples the equalised signal at a fixed 24-bit and 192 kHz, and a computer recognises the device as USB-Audio without a dedicated driver, so any recording software can capture the stream.

Pairing

The low-impedance output can feed a line level input on a receiver, preamplifier or integrated amplifier through one stereo RCA output. With its MM gain the stage matches ordinary moving magnet cartridges, and the higher MC gain and the adjustable loading cover low output moving coil designs. A PC or Mac connected to the USB port can record vinyl with free software such as Audacity.

Alternatives

The Vincent PHO-8 is another phono preamplifier from the brand and uses the same outboard power supply as the PHO-701.