Tested and seems to be working but due to its age it will need cleaning inside and out and most likely recapping at some point. Being sold as is.

HK770 from the early 80s(?) Works perfectly, but being sold as-is for parts or repair, as this is somewhere around a 40 year old amplifier. The cosmetics on this unit are not so good. There are scratches and a little paint missing…plus it needs a good cleaning (inside and out). Near zero dc on the output terminals. Hooked up a music source and it sounded great to me. Meters seem to function properly. Looks like the previous owner cut the power cord and added several feet to it (see photos). I let the unit run for several hours and it worked flawlessly. Let me know if you have any questions about the unit. Will need recapped eventually.

SPECIFICATIONS:Power output: 90 watts per channel into 8? (stereo)Frequency response: 0.15Hz to 180kHzTotal harmonic distortion: 0.08%Damping factor: 71Input sensitivity: 0.12mV (MC), 2.2mV (MM), 135mV (line)Signal to noise ratio: 74dB (MC), 73dB (MM), 75dB (line)Channel separation: 59dB (MM), 63dB (MC), 59dB (line)Dimensions: 443 x 134 x 398mmWeight: 10.3kgThis power amplifieramplifies but has distortion in one of the channels and it shows that someone tried to find the problem since one ofthe tantallium transistors on the bottom plate was placed on top.Returns are not accepted, please see the picturescarefully before purchasing the item, it is sold as seen inthe pictures

For sale: Harman Kardon HK 725 + HK 770 Ultrawideband Pre and Power amplifier from the golden times from Harman Kardon. A beautiful build and easy to serve versetile vintage audio sleeper. Harman Kardon HK770Stereo Power Amplifier (1982)SpecificationsPower output: 65 watts per channel into 8? (stereo)Frequency response: 20Hz to 20kHzDamping factor: 50Input sensitivity: 1.2VSignal to noise ratio: 123dBDimensions: 385 x 72.5 x 320mmWeight: 10.1kgYear: 1980 Stereo Pre-Amplifier (1980-82)SpecificationsFrequency response: 1Hz to 150kHzTotal harmonic distortion: 0.005%Input sensitivity: 2.3mV (MM), 145mV (line)Signal to noise ratio: 90dB (MM), 106dB (line)Dimensions: 385 x 72.5 x 320mmWeight: 4.2kgYear: 1980 Please do not hesitate to contact me regarding this offer or more detailed shipping and handling fees. Also feel free to follow my channel for more mostly vintage audio and speaker gear.Happy bid!

Harman Kardon, HK 770, amplifier

HARMAN KARDON : HK 715 : HK 725 : HK 770: HK 100M : Very rare vintage stereo system : The system consists of DC power amplifier , DC power pre - amplifier DC fm / am tuner and lastly DC cassette player . This system has been imported and works through a lower voltage than that used in the UK . There is a voltage converter supplied with the units to enable use within the Uk . Specifications are as follows : Twin Toroidal power ultrawideband direct current amplifier , 2 channel x 2 x 65 watts into 8 ohms , 20 Hz -20 kHz , damping factor : 50 , Input sensitivity 1.2 v , signal to noise ratio 123 dB , A - B four speaker outlet , dimensions 385 x 72.5 x 320 mm , weight 10.1 kg . Direct current pre-amplifier with switch button bass/ treble control function , frequency 1 Hz -150 KHz, total harmonic distortion 0.005% , input sensitivity 2.3 mV ( MM ) 145 mV ( line ) signal to noise ratio : 90 db ( MM ) 106 db (line) , dimensions 385 x 72.5 x 320 mm , weight 4.2 kg . Direct current tuner with am / fm step up / step down tuning , 87.5 MHz on frequency display , 96.2 MHz on frequency counter 999 KHz on frequency display , confirm that frequency reading on frequency counter is 1458 KHz : Direct current cassette player : Professionally serviced with receipt . For those who are familiar with this system words are few , for those who are not , they just do not make them like this anymore . Full metal chassis construction on all components .The pre-amplifier has a unusual switch bass / treble configuration with assisted EQ switch for refined precision listening , The power amplifier is heavy to lift and has several heat sinks on either side maintaining a good transference of heat for continuous long use . The cassette deck has various options for metal & normal tapes : And finally the tuner has a step up/ step down function for precise tuning ensures smooth transition from station to station. Light damage to the front of the power amplifier case (see picture nine ) and some usage marks to units over the years but given this system is over forty years old , the units are in good condition .This sale is for payment through eBay strictly and collection only as the system is to heavy for postage , plus the possibility of damage in transit enforces the reason for collection .In saying that I am willing to work with a buyer who wishes to arrange collection through service of a courier, but please note that I will not be held responsible for any damages which may occur whilst in transit. Please note the hi-fi stand is for display purposes only and is not included in the auction . Please DO not waste your time asking for a particular unit of the set to be sold separately, you will not receive a reply , serious inquiries welcomed .