Harman Kardon PM665

Spring cleaning and clearing has made this very fine amplifier available for sale to you. Over the winter I completed a restoration on this PM665. The end result is great sounding and visually beautiful amplifier. The face plate is free of scratches and nicks as is the top and sides. The back has a couple very light scratches. Outside of that this unit is in very good condition. Under the hood is where the magic really shines. All of the electrolytic capacitors(including the 4 filter capacitors) were replaced with Nichicon, Panasonic and Cornell Dubilier capacitors. Wima film capacitors were used to replace the smaller values where space permitted. The power supply was completely rebuilt as the components had been subjected to excessive heat and were weak. The transistors were replaced, new diodes and resistors installed. All of the connections to the power supply were reflowed to eliminate any cracks and cold solder joints. On the drivers board, The same treatment was applied. The differential pairs were replaced with new transistors that were gain matched and glued together and then encased with shrink tubes so that the temperature changes remain the same across both transistors in the pair. The controls were cleaned and lubricated. Where possible, the control mechanism was disassembled so the cleaning could reach every part of the control. This is documented in the photos that show the slide control being disassembled and cleaned with De-Oxit and lubricated prior to re-assembly. On the output stage, the transistors were removed and the old heat transfer compound was removed. In place of the compound and Mica insulators , Silicon pads were used. This will eliminate any future need to replace the compound once it would have dried out. The trimmer resistors were upgraded to multi-turn Bourns units. This provides a greater level of accuracy when setting the DC Offset and BIAS. All thru the preamp and the input boards, the selection of new components was made with goal being to reduce noise and impedance. Once the restoration was completed, I set the DC offset and the BIAS to factory specs and then played the amplifier for the next 40 hrs. at varying volume levels while monitoring the BIAS and DC Offset. (This amplifier is rated at 100 watts/channel which is a little conservative as I was able to produce 112 watts before the amp started to clip) The settings held steady and didn't drift. I used this amplifier for the 3 months without any issues. At one point I set the amp to the "Separates" setting and used an external preamplifier and used the amp just for the amplifier only. It sounded really great and performed flawlessly. This amplifier has a great sounding bass and very detailed upper frequencies. The PM665 flies under the radar most of the time as many people are unaware of just how good a amplifier this is. This was produced just as Harman Kardon was at their zenith. As the 1970's ended the Watt Wars came to a close and the market changed. The emphasis moved from great sounding and great looking stereo to building units to a set price point which saw the introduction of black plastic stereos that no longer had that wonderful sound. Gone were the polished aluminum face and control knobs. The decade of the stereo wars was over and what was left was cheaply built stereo units that all looked the same and lacked that sound that we all knew and loved. Sure you could still buy new stereos that retained the sound and looks but the cost was more than the average person could afford as those were manufactured by hand for the most part and in very limited quantities. The same is true today. Those wonderful stereos are still available if you have the money to buy one new. The other option is to buy one that survived the last 40-50 years and has been restored. A properly restored and maintained stereo that just lasted 50 years should be able to last another 40-50 years. If you made it to here, thank you ! Upon the purchase of this amplifier I will double box the amp to protect it during transit.

Specifications

Power output: 100 watts per channel into 8Ω (stereo)

Frequency response: 0.2Hz to 150kHz

Total harmonic distortion: 0.08%

Damping factor: 65

Input sensitivity: 0.12mV (MC), 2.2mV (MM), 135mV (line)

Signal to noise ratio: 75dB (MC), 77dB (MM), 78dB (line)

Dimensions: 443 x 134 x 398mm

Weight: 13.5kg (29.7 lbs.)