Phase Linear 4000 Preamp & (2) 400 Power Amps

Quadraphonic setup

Phase Linear 4000 Autocorrelation Pre-Amp

The 4000 Autocorrelation Preamplifier was a collaboration design by Bob Carver and Bill Skinner.  It was designed to expand or uncompress the sonics of recorded material.  In audio parlance, it is called dynamic headroom.  In the midst of all the knobs and toggles is the four channel balance joystick.  

The 4000 has the capability of controlling up to six components: a tuner, two tape decks, two turntables and an auxilliary.  It has three switched and three unswitched AC plugs.  The 4000 was manufactured from 1973 to 1977.  It is still highly sought after today.

This unit is in good shape both functionally and cosmetically.

PL 4000 Features and contols:
Inputs: Phono1, Phono2, Aux, Tuner, Tape1, Tape2
Outputs: Front Main, Rear Main, Aux, Tape1, Tape2
Controls: Volume, Joystick 4 Channel Balance, Left & Right Treble, Left & Right Bass, Unlimit Threshold, Correlation Threshold, Peak Unlimit on Expand, SQ 4CH/2CH. Active Equalizer In/Out, Stereo/Mono, Correlate In/Out, Tone Turnover Frquency select 40/150/2K/8K Hz.

Phase Linear 400 Ampifiers

The 400 amplifier was, perhaps, Phase Linear's most popular amplifier due to its more than adequate 200 watts per channel and reasonable price tag.  The 400 was introduced in 1972 with a list price around $500.

PL 400 features:
Twin output VU meters.
8 output transistors per channel.
Factory rated frequency response of 5-250 KHz
200 Watts per channel.

There are 2 versions of the 400 before moving to the 400 II model. This pair is the improved version of the 400 with the same additional heat sinking used in the 400 II model.

The 2 amps combined provide 4 channels at 200 Watts each. Both amps work and sound excellent. One Amp has a small scratch on the front face plate and the VU meter light is burnt out (easily replaced). The other amp has a 1/4" hole in the left most side of the faceplate where some chimp put a On/Off toggle switch. Despite the hole, cosmetics are still good and the VU meter light works.


All equipment is working. Enjoy!

The Pre-Amp Weighs about 18 lbs.
Each Amp weighs about 37 lbs.

Get a better look!

 View Amp 1 < -- -- > View Amp 2

 Click on each picture to view larger

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