At the time (1983 – 1985), Harman Kardon said they had designed the PM660 to be the ultimate integrated amplifier, and I must say that its smooth, crisp sound really impressed me.
It is a very muscular 80-watt amplifier that has no shortage of power or clarity.
As with HK’s other components, its power rating is deceptively conservative. It can deliver 80 pure watts into 8 ohms hour after hour. But when the music starts demanding more, the HOC’s design has plenty in reserve.
Four rows of black anodized sharfin heatsinks and a properly isolated phono stage.
An MM/MC selection switch and a four-way capacitance adjustment for phono 1 that is MM.
Healthy, reliable and very powerful.
In terms of features, the PM660 has everything an audiophile needs. Like variable intensity bypass, accommodations for two cassette decks and two pairs of speakers, as well as high and low filters. In addition, two-way cassette copying, audio muting, tone correction, and a mono/stereo/stereo reversing switch.
In addition, a Tape Out selector lets you record from one source, such as your tuner, while listening to another, such as your turntable.
For the ultimate in critical listening, the PM660 also gives you a Main Direct switch that routes the audio signal directly from the Function Select switch to the power amplifier. This completely eliminates balancing, tone control, mode and filter circuitry, providing the simplest signal path for the highest fidelity.
One detail, instead of abruptly turning the speakers on with the “click” of a relay, the 660 introduces sound with a smooth transition from silence that takes no more than a fraction of a second, a small thing no doubt, but Harman Kardon prided themselves with this amplifier by paying as much attention to detail as they do to the basics.
Despite its unobtrusive appearance to an audiophile, the PM660 is undoubtedly a great value integrated amplifier. By any standard.
Power output: 80 watts per channel into 8Ω (stereo)
Frequency response: 4Hz to 140kHz
Total harmonic distortion: 0.06%
Signal to noise ratio: 78dB (MM), 80dB (line)
Semiconductors: 100 transistors, 16 diodes, 20 zener diodes, 2 bridge diodes, 2 varistors
Dimensions: 440 x 130 x 403mm