The System 4000 amplifier and FM tuner looked very much like the System 3000, but the entire circuitry had been redesigned to give an output of 17 watts per channel. It received a somewhat ambivalent review in Tape magazine of June 1974. According to the reviewer,

The test result table shows that, in almost every area, the amplifier exceeds its manufacturer's specification. At the time of testing it was mistakenly thought to be a 20 watt amplifier. None of the figures gave any reason to doubt this and only when checking the price with the manufacturers did it emerge that the rated output was only 17 watts rms power.

For an amplifier intended to produce 20 watts per channel the results would be good; for one of 17 watts rating they are generally excellent ...

This is an amplifier that I would buy for myself if the manufacturers could sort out one or two minor problems with production. As it stands, the System 4000 is a triumph of engineering and design over production quality control.

Although it was heavily advertised in specialist hi-fi magazines, the System 4000 never really took off. Even so, it sold well enough to justify its continued production until late in the 1970s.