Предусилители — Line Magnetic LM-44

The LM-44 is a Line Magnetic tube preamp that recreates the Western Electric 44 together with a WE 20B style power supply, a pairing also sold under the combined name LM-44 and LM-20B. Line Magnetic dates from 2005, when two brothers opened a lab for restoring and building copies of classic American studio and cinema audio from Western Electric, Altec and Jensen, and the LM-44 continues that work with triodes taken from the Western Electric catalogue. Line Magnetic classes the LM-44 among its retro preamplifiers.

Key specs that matter

Gain is rated at 10 dB, an input impedance of 100 kOhm and a frequency response of 20 Hz to 20 kHz measured at 1 W. The main chassis is narrow, at 215 mm wide, 225 mm high and 460 mm deep, and it weighs 10.3 kg net. A second enclosure houses the power supply, which keeps the supply transformers apart from the audio circuit.

Engineering and use context

The signal circuit uses two 101D triodes and one 205D, both types that carry original Western Electric designations. The separate power chassis holds five further valves - a 300B, a 5U4 rectifier, a 313, a 6J7 and a 6X5 - giving eight tubes in the complete preamplifier. The design description states that splitting the supply into a dedicated chassis is intended to reduce electromagnetic interference reaching the amplifying stages. Line Magnetic states that every one of its products gets hand-made point-to-point wiring in the firm's own two plants, and that it keeps classic schematics while using current production parts. The same catalogue contains a transformer volume controller called the V-02, the LM-1126 + 20B dynamic expanding preamplifier and the LM-129, and the brand also builds valve amplifiers around EL34, KT88, 300B and 805 output tubes. Its range further includes phono preamplifiers and digital-to-analog converters fitted with vacuum tube output stages.

Pairing

The LM-44 offers moderate gain for bringing a line source up to power amplifier level. Its high input impedance asks little of a CD player, streamer or phono stage. Because the main unit is narrow, it and the supply can stand side by side. A Line Magnetic 300B or 805 power amplifier keeps the system inside the brand's own valve range.

Alternatives

Line Magnetic also makes the G-2 preamplifier, which uses 6SL7 and 6SN7 double triodes with a 5U4 rectifier, has 15.6 dB of gain and includes a remote volume control.