Фонокорректоры — ModWright Instruments PH 150

The PH 150 is an all-valve, transformer-coupled phono stage from ModWright Instruments of Amboy, Washington, which the company calls its Reference Phono Stage. MM and MC pickups each have their own input, and power comes from a separate solid-state PS 150 supply connected by a 1.2 m eight-pin umbilical cable. ModWright's range also includes the PH 9.0 series of valve phono stages.

Key specs that matter

ModWright uses two 6C45 and two 6922 valves, with 6DJ8 and 7308 as possible substitutes for the 6922. Maximum gain is 72 dB for moving-coil and 57 dB for moving-magnet cartridges, and a front-panel control attenuates it by 0, 6 or 12 dB during play. MC loading is resistive at 10, 50, 100, 200, 500 or 1,000 ohm. MM loading is fixed at 47 kOhm, with capacitance of 0, 100, 220, 330, 470 or 680 pF. There is one RCA input pair for MM and one for MC, and outputs are an RCA pair and a fully balanced XLR pair, selected by a rear toggle. Frequency response is 20 Hz to 20 kHz ±0.2 dB. The phono stage measures about 432 x 127 x 305 mm and weighs about 8.6 kg, and the power supply about 267 x 127 x 216 mm and 6.8 kg.

Engineering and use context

The 6C45 is a high-transconductance triode suited to amplifying very small signals, and the 6922 double triodes follow it in the gain chain. Transformer coupling at the output provides the balanced XLR output and separates it galvanically from whatever preamplifier follows. The separate PS 150 supply keeps the power transformer away from the sensitive input circuits, and ModWright recommends placing it at a distance from the phono stage for the lowest noise. Front-panel controls select MM, mute or MC and switch between mono and stereo, which helps with mono records. A rear toggle inverts phase, and a ground lug takes the turntable's earth wire. After power-on, the output stays muted for about 25 seconds while the valves stabilise. The gain attenuator allows the output level to be matched to the rest of the system without changing cartridge loading. The PS 150 uses a 1.5 A slow-blow fuse on 120 V or 0.75 A on 240 V. ModWright gives a five-year warranty.

Pairing

The balanced XLR output suits ModWright's own preamplifiers and integrated amplifiers such as the KWH 225i, and other balanced preamplifiers. With its high MC gain and six load settings, the PH 150 accepts low-output moving-coil cartridges directly.

Alternatives

The ModWright PH 9.0 is another valve phono stage series in the ModWright range.