Accuracy: A low range ac voltmeter offering a performance close to that of a full specification vu meter. Suitable for connecting across a 600 ohm line and self-contained except for requiring an external 3k6 resistor. Calibrated for use with a 3k6 ohm resistor 4vu above the scale marking so that the reference deflection (0vu) is produced by a signal 4vu above 1mW in 600ohms (1.228V). The response curves below give a comparison of the full specification vu meter with that of typical AL19, AL29 and AL39 meters. A variation in over swing between 0 and 5% can occur since the damping is not individually adjusted on each AL meter but allowed to fall within normal process parameters.
Operating Temperature: -13°F to 131°F (-25°C to 55°C).
Performance: IEC 268-17.

Publication: Why Sound Engineers Still Prefer Analog VU Meters in Recording Studios
Publication: VU Meters in High-End Sound Systems

Accuracy: A low range ac voltmeter offering a performance close to that of a full specification vu meter. Suitable for connecting across a 600 ohm line and self-contained except for requiring an external 3k6 resistor. Calibrated for use with a 3k6 ohm resistor 4vu above the scale marking so that the reference deflection (0vu) is produced by a signal 4vu above 1mW in 600ohms (1.228V). The response curves below give a comparison of the full specification vu meter with that of typical AL19, AL29 and AL39 meters. A variation in over swing between 0 and 5% can occur since the damping is not individually adjusted on each AL meter but allowed to fall within normal process parameters.
Operating Temperature: -13°F to 131°F (-25°C to 55°C).
Performance: IEC 268-17.

Publication: Why Sound Engineers Still Prefer Analog VU Meters in Recording Studios
Publication: VU Meters in High-End Sound Systems