Фонокорректоры — Audio Research PH9

Audio Research's PH9 is a phono preamplifier with valve gain stages, made by a company founded in 1970 with its headquarters and production in Maple Grove, Minnesota. Everything is housed in one chassis, and the signal path is built around a trio of 6H30P dual triodes, which the maker describes as a simple and clear path from cartridge to output.

Key specs that matter

RIAA accuracy is held within 0.2 dB from 5 Hz to 20 kHz, and the 1 dB points fall below 0.3 Hz and above 80 kHz. Distortion stays under 0.015% at 3 V RMS output at 1 kHz, and noise is 77 dB with shorted inputs. Cartridge loading is selectable between 47k, 1000, 500, 200 and 100 ohms, so both moving-magnet and low-impedance moving-coil designs can be matched. Maximum input is 80 mV RMS at 1 kHz. Output impedance is 200 ohms. Rated output is 0.5 V RMS from 10 Hz to 60 kHz into a 100k ohm load, and polarity is non-inverting.

Engineering and use context

Beyond the three gain-stage tubes, one 6550WE and one further 6H30P work in the power supply. Low and high voltage supplies are both electronically regulated, line regulation is better than 0.01%, and an automatic two-minute warm-up and brown-out mute protects the output at switch-on and during mains dips. The load setting can be changed on the fly from the supplied metal remote, and a menu system covers cartridge impedance, tube hours and auto shutdown. Six front push buttons handle power, menu, option, enter, input and mute. Mains versions exist for 100 to 125 V at 60 Hz and 200 to 250 V at 50 or 60 Hz, with consumption of 120 W maximum and 2 W in standby. The chassis is 48 cm wide and 34.8 cm deep, the handles extend 4 cm forward of the front panel, and the net weight is 7 kg, rising to 10.7 kg when shipped.

Pairing

Audio Research specifies the following line stage or integrated amplifier input as a load of 50k to 100k ohms with 100 pF, and sets the limits at 10k ohms minimum and 2000 pF maximum, which also caps the total capacitance of the interconnect run. The maker describes the PH9 as suited to most cartridge and turntable combinations, with the five load steps chosen from the remote while a record is playing and the gain-stage tube hours tracked in the on-screen menu so replacement can be planned.

Alternatives

The Audio Research Reference Phono 10 is a two-chassis dual-mono phono stage with switchable Low and High gain and selectable Columbia and Decca equalisation curves.