Harman Kardon HK 775 mono amplifiers

[doucanoe]

I haven't purchased any solid state electronics for some time but I just couldn't pass these up. They are Harman Kardon HK 775 monos from the early 80's. I had never even seen a pair of these in the past and thought that others might be interested in checking them out.

The interior pic is off the internets. I haven't quite figured out how to get into them yet.

Harman Kardon HK 775
FIRST MANUFACTURED: 1981
LAST MANUFACTURED: 1983
SPECIFICATIONS:
General
Power Output : 130 watts, RMS/ch into 8 ohms from 20-20kHz with < 0.03% THD
Power Bandwidth : < 8Hz to 100kHz at 65 watts/ch with < 0.03% THD
Total Harmonic Distortion : 0.006% at rated output
Intermodulation Distortion : < 0.02% at rated output (60Hz - 7kHz)
Frequency Response : below 1Hz to beyond 300kHz +0, -3dB
Damping Factor : > 100
Slew Rate : 150V/ usec into 8 ohms@rated power output
Rise Time : SQUARE WAVE - 1.2usec into 8 ohms @ rated power output
Square Wave Tilt : < 2% at 20Hz
Transient Intermodulation Distortion (TIM) : < 0.007% at rated output
Crosstalk : 0
Each amp uses one toroidal transformer with + and - supplies
High and low voltage supplies for output and driver stages
Signal-to-Noise Ratio : 123dB (IHF-A)
Input Impedance : 24k ohms
Sensitivity : 1.2 volts for rated output

RC

 

[doucanoe]

Guts.

RC

 

[SoCal Sam]

Congrats! I've heard a pair of 775's on NS-1000M's and I was very impressed with the clarity and accuracy. They were playing the patching HK preamp (825?). The NS-1000M will punish sloppy amps and they will reward great amps, which IMHO, the 775 is. My tech tested them for square wave reproduction and the traces look fantastic at 20 Hz, 1 kHz, and 20 kHz. For the price, the performance is better than some very expensive amps I have seen on the scope.

 

[doucanoe]

Thanks. I think HK was somewhat sliding off the map quality wise during this period but I believe these to be part of their "high end" offerings at the time. I'm looking forward to hearing them after they have been gone over once or ten times. They might be a nice candidate for a rebuild.

RC

 

[redcoates7]

http://www.thevintageknob.org/THEVAULT2/HK700/HK700.html

As usual, Alex has the information online for the good stuff

Great little amplifiers...very good sounding IMHO...I like them quite a bit better than the matching preamp

 

[secondslc]

They might be a nice candidate for a rebuild.

RC

my ears perked up

In all honesty, the citation 17 pre and 730 receiver I have from them are built like tanks, and have never given me a lick of trouble.

Congrats ron....and welcome back to the dark side

 

[doucanoe]

my ears perked up

In all honesty, the citation 17 pre and 730 receiver I have from them are built like tanks, and have never given me a lick of trouble.

Congrats ron....and welcome back to the dark side

Yep, I have had the 430, 730 and 930 receivers. They are actually my favorites of any of the mid 70's receivers available at that time. My 430 sounds more like a tube amp than some tube amps I have heard

These might be fun ones for you to work on. I have already found the Technical manual with schematic online :thmbsp:

RC

 

[secondslc]

These might be fun ones for you to work on. I have already found the Technical manual with schematic online :thmbsp:

RC

Half my work is done! I'll be MORE than happy to check those guys out. Wanna help re-foam 12 imperial 9 drivers?

 

[theophile]

doucanoe,
I owned the integrated amp from that series,many moons ago.It was in a system which to this day,I still remember with fondness(and so do friends who heard it!).
I found the integrated to be very 3D,and remarkably lifelike.
I'd love to try a pair of those monos in my present system.

 

[Redboy]

Focus RC, focus!!!

 

[doucanoe]

Half my work is done! I'll be MORE than happy to check those guys out. Wanna help re-foam 12 imperial 9 drivers?

Sure :yes:

Focus RC, focus!!!

Just a mere momentary sidetrack

RC

 

[Inspiribomb]

pretty cool, Ron! Those look very nice, I thought about picking them up myself, but decided to pass. I'd like to hear them sometime.

 

[Hokieman]

Thanks. I think HK was somewhat sliding off the map quality wise during this period but I believe these to be part of their "high end" offerings at the time. I'm looking forward to hearing them after they have been gone over once or ten times. They might be a nice candidate for a rebuild.

RC

The only thing HK was losing ground on in those days was the "horsepower", or Watts Per Channel RMS wars, as well as the market share battle. In terms of quality of sound, power headroom, and clarity of sound for SS gear, I'll contend that the early 80's HK stuff could more than hold it's own with whatever its Japanese competitors were producing. Those of us who own both can appreciate the differences. My old HK570i still make my JBL's sing better than my big Marantz or my new old Pioneer. Here's hoping your new acquisition only needs the minor touch-up that most of these units require to stretch their legs again. The pure simplicity of these amps should make that likely.

 

[bryblob]

I must of called after you, he said a guy was coming to pick them up from an hour away, Oh well at least someone who will appreciate them got em

 

[VinylHanger]

I have a pair of those. I was using them hooked up to my Denon PMA-920 pre section and I love them. I have a few small issues with mine, but they will be singing soon. They are great amps, you will love them. :yes:

 

[doucanoe]

I have a pair of those. I was using them hooked up to my Denon PMA-920 pre section and I love them. I have a few small issues with mine, but they will be singing soon. They are great amps, you will love them. :yes:

I should get to them sooner or later. Glad to hear you are happy with yours. Sounds like they are going to make for some nice amps!

RC