This piece of equipment is used in stereo systems has a reference circuit that allows the reference signal to be phase shifted. Because this is a high voltage preamplifier it was made to pre process the signals and amplifies them for the demodulator. The demodulator then takes the signal and multiplies it together with the other signals. If the phase is adjusted for the reference signal the noise signals well be present when it reaches the output.

The Phase Linear 400 amplifiers also featured twin output meters and had six output transistors per channel, along with two drivers per channel. The heatsinks in the phase linear amplifier changed in this second generation, they were made in a different design that used less surface area and it was factory rated with a 5-250k HZ frequency response.

After the 1978 release of the Phase Linear 400 Series Two Bob Carver sold the Phase Lenear Company to the Pioneer Electronics Corporation and he then founded the Carver Corporation in 1979. Pioneer then added a high end cassette to the Phase Linear line. This addition did nothing to boost sales since the departure of Bob Carver and Pioneer then sold the Phase Linear line to Recoton. Recoton to date manufactures car stereo equipment.

There are still many of the Phase Linear 400 amplifiers in working condition and even replacement parts that can be found to make repairs on the amplifiers. Consider using these amplifiers with surround sound speakers or add an HD radio tuner.

Still not sure about the difference between phase amplifiers and preamp amplifiers? Read more on pre amps and see the differences.