Прочие устройства — Line Magnetic PR-23-22

The PR-23-22 corresponds to the unit Line Magnetic Audio of Foshan, China, calls the PR-22 Combined Excitation Power - a three-way field coil supply in a 485 x 320 x 450 mm case. It sits in the PR series of excitation units beside the PR-3, PR-5 and PR-12, and it exists to feed DC to the magnet windings of field coil drivers rather than to amplify any signal. It is the only three-way combined unit in that series.

Key specs that matter

Line Magnetic describes the PR-22 as an adjustable supply with vacuum tube rectification, aimed at drivers that need low voltage but high current. Mains input is 220 to 240 V AC or 100 to 120 V AC, both at 50 to 60 Hz. Three output selections are provided. The LOW terminal delivers 10 to 24 V DC, and the MID and HIGH terminals each deliver 3 to 10 V DC, all at 0.5 to 2 A. Rectification is handled by four tubes, either EL-6C types or the interchangeable EQ1-6/0.325. It weighs 39 kg.

Engineering and use context

A field coil driver replaces the permanent magnet with a second winding, and the magnetic field only exists while DC flows through that coil. The supply therefore becomes part of the loudspeaker motor, and its stability decides how steady the magnetic gap stays. Line Magnetic bases the main circuit on the Western Electric 4144 and uses some Western Electric materials inside. A pointer meter shows the output current, so the owner can set the excitation level by eye instead of guessing from a knob position. Splitting the output into three terminals lets one chassis energise several drivers of a multi-way horn system at once, each on the voltage band it was designed for, which removes the need for a separate box per driver.

Pairing

The maker names the drivers each terminal suits. HIGH and MID accept two 597 units or a single 597, one 555, one LM-755ex, one 594 or one RCA-1428. LOW takes two 555 drivers, a 594 or two TA-4181 units. Owners of other field coil drivers should check that the required voltage and current fall inside these windows before connecting, since the supply has nothing to do with the amplifier side of the chain and works with any tube or transistor amplifier driving those speakers.

Alternatives

The Line Magnetic PR-5 is a smaller single-tube excitation supply of 290 x 210 x 316 mm with a high terminal of 6 to 23 V and a low terminal of 2.6 to 8 V.