Предусилители — Line Magnetic VV-3

The VV-3 is a 300B based line preamplifier from Line Magnetic, a business formed in 2005 by two brothers who first specialised in fixing and reproducing Western Electric, Altec and Jensen products. Line Magnetic describes it as the first commercial valve preamplifier to use transformer volume control, and only a limited number were built before parts supply problems ended production. Its transformers were designed to follow Western Electric practice.

Key specs that matter

Gain is 15.6 dB, and an input of 330 mV produces 2 V at the output, with a maximum output level of 8 V. Input impedance is 100 kOhm, and output impedance is 600 Ohm at most. Frequency response covers 10 Hz to 30 kHz within 1 dB. Noise sits more than 90 dB below signal, and the quoted THD figure is 0.3 percent. There are three inputs, two on Cardas RCA sockets and one on a Neutrik XLR, and two outputs, one Cardas RCA and one Neutrik XLR. The unit weighs 14.4 kg.

Engineering and use context

Instead of a potentiometer, the VV-3 sets level with a ladder type transformer attenuator operated through a very large volume knob. The output stage runs on four 12AU7 double triodes. The power supply follows the Western Electric WE20A pattern and holds a 300B, a VR75 or OA3 voltage regulator tube, a 12AT7, an EF86 and a 5AR4 rectifier, so rectification is done by a valve. The output transformers come from Lici Audio, whose iron cores were developed as audio transformers in the Western Electric style and wound with British enamelled wire. Units were supplied for local mains, with 240 V versions for Australia. The company builds its electronics with hand-soldered point-to-point wiring in two factories and describes its approach as keeping mid-century schematics while fitting modern components. The company also makes a separate transformer volume controller, the V-02, that uses the same attenuation principle, next to the LM-44, LM-129 and LM-1126 + 20B preamplifiers.

Pairing

The VV-3 can connect to a power amplifier by XLR or RCA cable. Three line sources can be connected at once, for example a DAC, a tuner and a phono stage. The brand's own tube power amplifiers use 300B, 805, EL34 or KT88 output valves and keep the system within one maker.

Alternatives

Another preamplifier from Line Magnetic is the LM-1126 + 20B, a two-chassis design based on the Western Electric 1126 with 11 dB of gain.