1
2
3
4
5
6
7
8
9
10
11
12
Firsts seem to have come naturally to Harman Kardon, they were the inventors of the first Receiver and then only a few short years later the first Stereo Receiver.
So it might have gone unnoticed that Harman Kardon was the first HiFi company to introduce true twin-power Receivers into the market with separate power transformers, rectifier circuits, and filter capacitors for each channel.
But their competitors did notice. From the mid-1970s onwards twin power supplies began to appear in receivers and amplifiers from brands such as Marantz, Pioneer, Sansui and Kenwood, but these only appeared in their high-end units and in many cases it was not as well designed and executed as the technology Harmon Kardon had introduced into even their low-end models!
Integrated originally into their 1972 product line up, Harman Kardon’s Twin Power design provided numerous tangible benefits and some that were more subtle. These included doubling the current load capacity, incredible dynamic power and incredible channel separation with a high dampening factor to deliver what HK described as “Ultrawideband Sound”.
The HK-730 Twin Power: Completely separate power supplies for Ultra-Wideband Sound!
Most collectors and enthusiasts know that the power ratings of most quality vintage amps are highly conservative. Even systems rated at 15 Watt RMS seem to out perform many modern amps rated at seemingly much higher values. This seems to be doubly true for this amp. Rated at a modest 40 Watts RMS per channel this amp packs a punch that simply KO’s amps supposedly rated much higher.
This was evident when in 1977 the Boston Audio Society performed a comparison study in which the baby Harman Kardon 330C receiver rated at only 20 watts RMS per channel outclassed a 75 watt RMS per channel Marantz 2275 in some tests!
The Harman Kardon 330 – Marantz Killer???
Harman Kardon stated in their advertising material the conservative nature of the power ratings on these models, and they were right! Very rarely will you need to take the volume past 33% on this unit! (with exception to party animals and rock stars of course).
The HK 730 was the top-of-the-line model for their x30 range but they did offer an audiophile high-end series which they labelled Citation – but that’s another story!
Two amps were released that year in this class with the twin power supply design, the 430 Twin rated at 25 watts RMS and it’s big daddy 730 Twin.
These units along with their older cousins the 930 and the 630 have recently been (re)discovered by audiophiles and are rapidly gaining in popularity, with many preferring these units to high end Marantz, Sansui and Pioneer.
This model was also equipped with a uniquely patented Harman Kardon tuning section which measures not signal strength but signal to noise ratio, allowing for precision tuning for the purest sound possible.
I absolutely adore the styling of this amp with the large perspex black tuner and backlit indicator section and the aluminum fascia featuring Helvetica lettering! On a purely aesthetic note this unit works well to blend modern black HiFi components in a stack with the classic silver faced components.
The analog controls include contour (loudness), high and lo-cut, speaker selection, bass treble and volume controls. What I love about this unit is the abundance of inputs including two auxiliary and two tape inputs with options for tape dubbing, and one of my favourite features is the two turntable inputs which makes playing vinyl at parties easy and a lot of fun!
High Fidelity Review has to say this about the Harman Kardon 730:
“The 730 is exceptional in all these regards. Background noise is almost non-existent allowing for a perfect canvas onto which to “paint” music. Bass tones are always satisfying, and midrange and treble are very clear. Clipping is graceful, resulting in slightly compressed sound, but no apparent DC nasties. The 730 also demonstrates extraordinary tonal balance. The bass and treble controls are virtually unneeded the sound from the amplifiers is naturally so full and well balanced.” http://www.highfidelityreview.com/harman-kardon-730-receiver.html
SPECIFICATIONS
Tuning range: FM, MW
Power output: 40 watts per channel into 8Ω (stereo)
Frequency response: 4Hz to 130kHz
Total harmonic distortion: 0.1%
Damping factor: 30
Input sensitivity: 2.5mV (MM), 150mV (line)
Signal to noise ratio: 72dB (MM), 77dB (line)
Dimensions: 432 x 368 x 140mm
Weight: 13.7kg
Posted In: Receivers
Tim
·
Harmon Kardon? Not familiar with that co. I always thought is was HARMAN KARDON! Anyway, one of the amazing things about audio equipment reviews is that they are seldom negative. I have a 730, 670, 680, 690, 570, 880, 6900 integrated amp and a 3350. Of all of these, the 690i is the best sounding, but the 6900 is the best performing. The 730 is dynamic, but easily agitated and sounds rushed, trying to catch up to the music. The 690 is sweet and round sounding. The 6900 has great authority and general push. The best mid range, low mid and bass clarity, depth and accuracy (it is after all more than four time the rated power of the 730 and 13 years newer). Let’s be honest, the 680 and newer (don’t know about the post 90’s stuff) really outperform the 730. Nostalgia is a warm fuzzy that can’t make the sound better.
admin Author
·
Thanks for the proof read, and in the title line too! I usually dismiss out of hand pretty much all major-brand gear post 82 as junk with a few exceptions, however I have heard a few people tell me the Harman Kardon (correct spelling!) from the 80s is pretty good. Sounds like yours might need a good service, have you checked the DC offset and the caps?
Tim
·
I’m no expert on anything Harman after 1991 or so, (I have an 880VXI and a 3350 receiver), but the thought of buying “audiophile” equipment that is made in China and all software and computer chips doesn’t excite me. That said, my DAC is all chips and made in Thailand, I believe. Each of the generations of HK gear have a distinctive character, and each has btw, been serviced. The 730 is nice for low mids and up. Vocals and guitar are really great. Always dynamic. The 670 is a completely different beast. Much more depth, range and air. Not as tight, but bigger feel. The 680i is just amazing. It disappears. So accurate, true and round. The 690i has just a bit more reach and punch. It is also better looking in action, with only a single led on. The 6900 is again a completely different tool. Much more powerful, great range and about as neutral as possible. Definitely not as “sweet” but it plays speakers without coloration. I forgot the PM665. It bridges the tradition power supply era and is true twin power. Much more powerful than its 100wps would suggest. So there you go. I don’t how they compare to modern. I don’t like my music to sound processed or manufactured. I also think it best to avoid equipment with built in processors since this tech is changing so rapidly. I wonder how these sound compared to the Citation 16a or a Luxman R117? Thanks
Jake Swa
·
You are dreaming big time. Any HK after the 70’s can’t hold a candle. Not sure what you are listening to but maybe get your ears tested! I compared the Hk 402 with the 6500 etc. What a copout. Get the amps built in Japan and California and maybe Taiwain. Before Sidney Harman sold his company and before the iold embargo when mass machine production and cheap components set in.
Heath Dickerson
·
Just plugged in a garage sale Harman Kardon 730 they thought was toast . The lights are out and the pre-amp connectors were mia, rca’s to the rescue, for now. Hooked it up to freshly refoamed,DIY Advent’s also a garage sale find and for a grand total of 25 smakaroos I’m stoked about the sound coming from this blacked out little receiver.
Spencer Carson
·
I’ve owned two Harman / Kardon 430 models. People seem to generally ignore them when they are in the store, but they are in my to 5 favorite receivers I’ve owned in the shop (a list which includes Mcintosh, Marantz, Dynakit, etc.)
Jamie Lynn
·
This is a great article about Harman Karkon (as are the many other articles on this site) I feel that vintage Harman Kardon models are mostly ignored when it comes to articles and blogs. I recently purchased a 1979 Harman Kardon HK 670 in near mint condition, now there is very little info out there about this model and even less blogs, what is out there is filled with people complaining in some form about it either being under-powered, ugly and so on. But I still took the risk and purchased it. And I can say it was a very wise purchase.
This receiver has Excellent sound quality and I belive that the 670 has the same underrated wattage as the 730 model in this article. I have it hooked into a pair of Pioneer CS-G203 120 watt speakers and at 33% of its volume it made those Pioneers practically jump off the floor, and the sound quality was amazing!!
So I did some checking on its specs and compaired it to others that were in the receiver wars. even though Harman Kardon wasn’t in the receiver wars because they didn’t have the wattage it is my opinion that they were keeping up in sound quality. This receiver when compaired to the Pioneer SX-1980 has the same THD overall and in certain areas has better THD than the monster Pioneer.
This receiver gets forgotten and left behind by many but I feel that it is the “sleeper” receiver during that time. More attention should be give to this outstanding performer from the late 70’s to early 80’s.
I love reading your articles and please keep writing them.
Jamie Lynn
Vintage-Man
·
As a long time collector of many vintage amps and receivers … Had many and still have many Marantz, Pioneer Sansui off all models .. Can say I’ve probably had close to every model made as I also repair these. The Marantz seems to be the “in” model to have today and most say they are “warm” sounding… Well I have a lot of the high-end models still today but my daily listener is the HK 730. Not sure what it is maybe the true dual mono-block design but this is the best sounding and out performs my high end minus the 150+ watts which are not needed in my case as Iam not in a stadium. I don’t go by the paper and read it’s specs- but it’s simple layout seems to be something magical and as far as the warm sound this is in my humble opinion the closest you’ll ever get with out getting into the Tube amps. Highly Recommended!!!