1977 saw another flurry of activity as those already in the competition released new models and some new players suddenly decided to enter into the Receiver War. It not only saw a quantum leap in terms of power but saw a new front in the Receiver War open up as well.
Technics SA-5770
It was not typical for HiFi manufacturers in the 1970s to have such a short product life-cycle, but Technics released the SA-5770 hot on the heels of their previous years model the SA-5760. It did not appear to have any appreciable difference to the SA-5760 and produced 165 Watts RMS @8ohms with 0.08% THD.
Inside it appeared much the same as the previous model as well.
The only reasons I can think of for it’s release was either that it was purely for marketing purposes – as in ‘Hey, look at our new model!’ or perhaps it was a bug-fix for the previous model??? (note: this is conjecture only and I am not aware of any actual problems in the SA-5760).
Yamaha CR-3020
Yamaha receivers from this period are renowned for their unique sound and are considered very high speed amplifiers with some vintage audiophiles suggesting that these amplifiers make regular speakers sound like monitors.
Up to this point Yamaha had been content doing their own thing but in 1977 they suddenly woke up to the markets demand for power and entered the melee with their CR-3020 Monster, equaling Pioneer SX-1250 with 160 Watts RMS per channel.
Yamaha utilised a laminate core dual-secondary power supply with 2x 27,000uf filter capacitors to drive the amplifier. But what was remarkable about this Receiver wasn’t it’s power output, it was that Yamaha had made marked improvement in total harmonic distortion reducing it down to 0.03% at its rated output of 160 Watts RMS across an amazingly wide harmonic spectrum of 5Hz to 100,000Hz!
This put the CR-3020 in a complete class of its own and heralded a new front in the Receiver War. Many manufactures had been content with a low THD rating of 0.1% however after the CR-3020, Monster Receivers now not only had to have the most RMS but also the lowest THD possible.
From a price perspective I have seen literature that indicated the the retail price in 1977 for this unit was $1,500.00USD which would make this the most expensive receiver we have yet seen in the war and would price this unit at around $5,890.00USD today! (2015)
Kenwood KR-9600
The 1977 Kentwood KR-9600 featured 160 Watts per channel RMS power and was powered by a laminate core transformer with dual secondaries and 4x 10,000uf capacitors. It was heavily promoted as featuring a dual power supply. With the release of this model it appeared that Kenwood were content with ‘keeping up’ in the Power Wars as opposed to breaking new records.
This model also saw a slight improvement of THD with a rating of 0.8% at the rated power output but measured over a much broader frequency spectrum of 5Hz to 50,000Hz, perhaps this was influenced by Yamaha CR-3020.
The amplifier was a Three-Stage design with the Power Amplifier Stage consisting of a Pure Complimentary Parallel Push-Pull OCL design incorporating a large IC Darlington Power Block to produce what Kenwood described as ‘exceptionally clear, smooth, silken sound’.
This Kenwood also included other great features such as Dual Stage, Triple-Tonal Controls, Dolby FM and Two Phono inputs with Dual Phono Pre-Amps to allow for a wide selection of cartridges.
Cosmetically this unit was a very attractive piece and was aimed at the ‘pro’ market by including rack mount handles and integrated left and right channel VU meters, a feature almost all future Monster Receivers would come to incorporate.
Another dark horse suddenly entered the Receiver War and raced to the top for a brief time and claimed the prize of having the worlds most powerful Receiver.
Not a name you would normally associate with high-end audio components today, Hitachi released in November 1977 the SR-2004 – a 200 Watt RMS per channel Receiver.
This surprising beast was built on a power supply of very similar design to Pioneer’s SX-1250 with a large toroidal transformer with dual-windings upon a common core and 4 filter capacitors with a combination of 2x 18,000uf and 2x 10,000uf caps.
This Receiver stands alone in the Receiver War with it’s unique Class G amplifier. Headroom in amplifiers from the mid 70s had been a big thing, but Hitachi claimed that this amplifier had the headroom to allow for brief periods to double it’s rated power output, apparently a feature of Class-G amplifier architecture. Reportedly this amplifier would run cool even when being pushed to it’s limits.
Hitachi being a electronics components manufacturer meant that almost all the components in this unit were produced by Hitachi with the exception of the transformer and the filter caps.
Again this amplifier was competing in the new front of the Receiver War and showed a slight reduction in THD with a rating of 0.08% across a broader frequency spectrum of 10Hz to 40,000Hz. Cosmetically this receiver was very similar to the Pioneer SX-1250, especially in it’s rear-end, however it incorporated the now highly popular Analogue VU meters into it’s fascia.
Dimensions: 580 x 186 x 447mm Weight: 25.5kg
Model 2500
Marantz who had been pro-active in the battle from the get-go, understood that it was pointless to merely equal their competitors power ratings. To maintain a dominant position in the market they had to SMASH IT!
And that they did with the release of the Marantz Model 2500 in 1977 with a thunderous rating of 250 Watts RMS per channel, beating the SX-1250 by a whopping 90 Watts RMS per channel, and Hitachi’s rating by a convincing 50 Watts RMS per channel!
Marantz had also moved to introduce a toroidal core transformer coupled to two ‘dual’ filter capacitors rated at 7,200uf x2 for a total capacitance of 14,400uf per ‘capacitor’.
The curious thing to note here is that this Marantz 2500 has less total capacitance then 
their previous top model the Marantz 2325 but was delivering double the power? I will leave the question as to how this would effect its dynamic power performance up to the listener.
The amplifier section incorporated Direct Coupling with a Quadrupled-Parallell Output Stage and the chassis was fitted with a cooling fan which would have required further shielding to prevent noise from leaking into the amplifier, however this fan apparently did its job very well and reportedly this model ran very cool even when pushed to its limits.
The Model 2500 also saw a marked improvement in Harmonic Distortion with a rating of 0.05% THD at it’s full power of 250 Watts RMS 8 ohms per channel measured between 20Hz to 20,000Hz.
An aesthetically impressive unit the Model 2500 also featured an oscilloscope display for added pleasure, along with all the bells and whistles one could expect in top model.
With an original retail price of $1,750.00 USD on release in 1977 would price this unit at over $6,870.00 USD in 2015, and make it the most expensive Receiver in the War to date.
Marantz had decisively won the power wars in 1977 in what can only be described as a quantum leap in power output. Marantz had once again made their mark as both leaders and innovators of High Fidelity.
Posted In: Article, Featured
Tagged: `, receivers wars
Drew
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Some people debate which was the first 100+ watt per channel receiver: The Pioneer SX-1010, the Kenwood KR-9400, or the Marantz 2325?
It doesn’t matter, they are all great receivers!
Drew
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Great write up on the Receiver Wars. However, it’s a shame that the Sansui G-8000 or G-9000 was not even mentioned because they were actually the 2 most powerful Sansui receivers of the 1970’s.
The 22,000 and 33,000 are NOT receivers. They are a separate power amp with a preamp/tuner.
admin Author
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Yes you are right! I did mention that Sansui (and Rotel) were technically CHEATING but decided to make allowances for it because the G22000 & G33000 are just so AWESOME! Maybe I am being corrupted by modern politics 😉 When I get time I will have to mention the G9000.
STDevil
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An absolutely lovely article. I was a young lad in the 70s when my dad bought a SX-939; not a monster but close to it. I enjoy vintage audio and apparently so do many others!
Terry tate
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Very good article well written
Spencer Carson
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Wow. Great info. I run a store in Seattle and I get to see this stuff on a daily basis. Though I haven’t owned most of these monsters I have had a lot of their smaller brothers in the shop including a Marantz 2330, Kenwood KR-7600, Sansui 5050, and many more! Thanks for writing such an easy to read fun article!
Spencer
Owner
Turntables & Trails
Seattle, WA
David G
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I just wanted to say thanks for putting this piece together. I have just entered the world of receivers in hopes of
buying my first. I’m a child of the 70’s, so it really is exciting to enter into this audio sphere. Your article
cleared up the issue of why so many receivers of that era seem to be so sought after, and at such premium prices !
Cheers for a job well done.
Bob
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I just bought two of the best. Marantz 2325 and Pioneer SX-1250. Waiting to rebuild them so I can hear what music can sound like from them.
Brandon
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A fun read and thanks for putting it together. I’m now a proud owner of a fully restored Marantz. Every cap , diode, transistors, extra soft start relay etc on every board has been replaced.
Let me say, it’s a privilege to hear this and I can’t thank enough the engineer who did this out of passion.
I’m a LUCKY individual to be hearing music so softly at times and thunderous at others while at the same times the delicate details of the music. The cadence , rhythm, attack and decay of handling 15″ woofers on my Klipsch Belle’s on VERY low volume at one in the morning while little one sleep is truly a sign of a great receiver.
Anyway, hearing so much about the musicality of Sansui G-22000/33000 I’ll be looking for one just out of curiosity.
Folks, get a Marantz 2500 fully “off the frame” restoration and you’ll never regret it.
Cheers.
maick
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I owned a Kenwood 9600. Great unit. I ran JBL L100s and L166s through it. It didn’t even blink.
Jason
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Interesting that Harman Kardon stayed out of these wars.
David
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Realistic STA-2080 anyone?
Benjamin Tarr
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I still own my Pioneer SX-1250. My father garbage picked it for me as a kid in the early 2000’s and to this day I still can’t understand why someone would just throw away a fully working beauty. . . . . Okay a few bulbs were burnt out and three knobs were missing but still fully functional (all fixed up now). Things like this normally are far out of reach for my budget so I feel extremely honored to own such a blessing. The warmth this thing reproduces is inviting even if you’re listing to MP3’s. It will even put most vacuum tube units to shame even through my cheep craigslist speakers. (I plan on getting some used “cheap” Vandersteen Model 2’s for it.) My bias is for the Pioneer but the truth is all vintage high fidelity receivers from this era are truly a class above anything made today. They’re envious inducing for all your friends so for the love of God don’t keep anything like that in your garage.
Lee Martin
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I have a Pioneer 1280, Sansui 9090 and a Marantz 2325. I love my 9090 and the other two are great. I just prefer Sansui products. I have never turned the volume above 2 and you can’t hear a person next to you. Crisp clean and loud. I also like some of the stuff Luxman put out there.
Lincolnman
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Nice write up. This is the most extensive chronological account I have seen of the major blows in the war. Most turn into a list of “all the monsters”.
The last page regarding the real purpose of this type of equipment seals the deal on this being a well thought out article.
ChefE
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I enjoyed reading the article. I thought you did a great job compiling the key elements of the receiver war for a historical and educational perspective in a nutshell and included specific specs on specific models of receivers as support . This article wasn’t meant to showcase all the wonderful receivers during that time. There’s other articles and debates on that. Every person involved in the receiver war has a favorite and excuses why others wouldn’t be given the time of day, even if they were better. Right Marantz people?
On another note- I’d like to think the real winners of the receiver war are the receivers that are still going strong, all original , without issues, and without the ‘for its age’ excuse.
Paulo Martins
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Amazing article!
I delighted to read these lines. Thank you for resurrecting the genealogy of these timeless monsters.
I’m just one more fan of these machines. Unfortunately in Europe followed the english model – integrated amplifiers and let pass completely these Ferraris…
In my collection i have 2 Marantz 2270, one Pioneer SX-850, one Pioneer SX-950, one Pioneer SX-1050 (bought 2 days ago) and the Sansui 9090, my all time favorite one!
in the future i want to get the SX-1250 and the Sansui9090DB.
Please write an article about the Marantz 2270. He is not one monster receiver, but he deserves it.
From Portugal,
Paulo
Paulo Martins
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It would also be good to write a review about the SX-1050, the little brother of the Pioneer SX-1250.
The Pioneer SX-1050 has “only” 120 horses :0)
Greg C
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Fabulous website! Thanks for all your work putting it together. One correction: Your quoted power of Yamaha CR1000 is wrong. Its correct RMS rating (20-20kHz at 0.1% THD), is 70wpc @ 8 ohms. IHF rating is 100wpc @ 8 ohms. Not “40wpc RMS” and “70 wpc IHF,” respectively, as stated in your article above. For reference, I cite the manufacturer’s original brochure, which can be found in the online HiFi Engine library. Thank you, in advance, for making this correction.
admin Author
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Done! Thanks for the info.
Cheers
Lutin
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Great job, i am Lucky cause i use à 5760 with infinity kappa, both in a mint condition. Only pleasure and strengh
À french man
Jason uk
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I have a pioneer sx1010 and feel privaliged to be a part of the receiver wars and this great era for hifi
Eric
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The Monsters little family members watched the war from a different side. These models may be known as “Mid-Fi”, “Lo-Fi”, or ‘If-Fi’. If I had way more money then I would’ve bought a Hi-Fi monster.
And eventually I did. Now I have that and everything in between. I love the big receivers but when I use the lower tier audio I’m more at ease since the big ones , if something should happen to them….it’s not that simple and cheap to remedy the situation. There’s more at stake. Then again the rewards are somewhat higher too, although that’s subject to debate.
What I’m saying is let’s not forget the ones in the garage, bedroom, basement, man cave, dorm room, spare room, office, the one you brought to the girlfriends house (future wives?) and the ones she made you get rid of in your house.
Huseyin Kavak
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Awesome article I love those receiver amplifiers use to own If I’m not wrong Marantz 2325 paired up with Bose 901 produced unbelievable sound me and my friends enjoyed many years to come, it was a magic decades.
Jordan Richards
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Nice article but lacking certain pertinent call-outs.. The monster Pioneer & Technics receivers had fraudulent power output specs, for example the SX1980 actually put out 145W/ch rather than the claimed 270W/ch. Both receivers had robust power supplies but inadequate heat sinking area, and Pioneer was slapped with a an FTC Case & Desist about their fraudulent claims for the SX-1980. Basic problem was that neither receiver would NOT pass the FTS preconditioning tests. When tested rock-cold the SX-1980 would put 270W/ch but… as the heat sink heated up its power output would decrease significantly… The only monster receivers meeting & exceeding the FTC power output specs were the Marantz 2385, 2500 and 2600.. I actually have serial # 0002 model 2600 hand carried back from Japan by a close relative, it is in mint condition and I have turned down offers of >$9,000.. Great product, plenty of power, scope, 5 gang front end, quartz lock tuner, full complimentary output stage, patented servo-controlled heat-sink tunnel output stage…
admin Author
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Hi, and thanks! Interesting… do you have any articles to the support the fraudulent power output spec claim?
I could not find any reference to FTC cease and desist orders other than 1 comment on another website that also lacked any source references.
What I did find was 2 independent lab tests that told a different story:
The folks at Audio Magazine in the September 1978 issue reported on their laboratory tests on the Pioneer SX-1980 using both the older FTC standard and the newer 1978 IHF standard (with the specified warm up). Both their tests showed that the 270 Watt RMS rating was very conservative, with the SX-1980 delivering more than the 270 Watts claimed.
The reviewer went even further to say:
“Though the new [IHF mandated] “Dynamic Headroom” measurement is specified in dB, it should be mentioned that based upon the short-term signal used to measure the 2.3 dB headroom of this amplifier, it was producing nearly 460 watts of short-term power under these test conditions!”
Then there is HiFi Stereo Review, the November 1978 edition that published their Hirsch-Houck laboratory tests of the Pioneer SX-1980 using the new standard – IHF-A-202 1978 which included the prescribed one-hour preconditioning period at one-third rated power, they stated that the unit did not become excessively hot during this stage. Their tests indicated that the 270 Watt rating was quiet conservative with clipping occurring at around 300 Watts with intermodulation distortion measured at 0.045 percent at 300 watts.
I will check in later if I find some independent lab tests for the Technics.
Douglas1879
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Planar brand quad receiver.
After trying low end Electrovoice EV1144 & Sanyo quads I finished up in 1976 with a (owned by Canadian Electrohome) Planar XR-4120 receiver, rated at 4×30/2×70 watts RMS 20-20 kHz at 0.5% THD, which could handle all quad formats including full logic SQ. I enjoyed RCA CD-4 and had a library of about 20 CD-4 + 40 SQ & 1 QS LPs.
I built my own 4 towers each using Philips drivers-1 8 ohm AD80652-W, 1 AD5061-M, 1 AD2011-S & 1 AD8002 passive radiator, and crossovers using data from Philips published ‘Building Hi-Fi Speaker Systems’ by M.C.Hull. Dual (forget model) turntable with (forget model) cartridge & Shibata stylus compatible with CD-4 high frequency requirements. I also had a joystick 360 degree speaker control. Unfortunately my enjoyment was short-lived, since while on vacation my house was burgled with only my system taken. Presumably one of my kids had been talking about it and one of their acquaintances had unsavoury connections.
Planar were late into the short-lived quad market and went out of business. I remember the hefty 50 lb weight, more than some much higher rated receivers, even although the power transformer was toroidal.
Douglas1879
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As an example of the advertising problem, before I bought my Planar XR-4120 I had a large French Provincial cabinet (by Drexel) Motorola credenza since my wife liked it as a piece of furniture. Multiband radio, turntable brand I forget, cassette player (motherboard Nakamichi) and 3-way (12 inch woofers) speakers. Advertised as 350 watts, but this was dynamic power rating for 2 channels, no distortion figure quoted, which translated into less than 20 watts RMS/channel into 8 ohms. European ratings had for years been based on continuous RMS at specified distortion levels, usually into 8 ohms. As a ‘Brit’ with exposure in family radio & TV business since age 10, I was familiar with both systems, living in Canada 1963-72 & 1976 on.
Tony
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Hi.
Just wanted to congratulate you on your FANTASTIC Site. Who is the brilliant Hi-Fi Journalist who wrote the article on the Receiver Wars ?
Tony
admin Author
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Hi,
Thanks for your feedback, much appreciated!
I am glad you are enjoying the site 🙂 This site is a hobby of mine to spread the love of vintage HiFi, unfortunately I haven’t had the time to contribute to it lately.
Cheers!
Rustam
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Where is famous Akai ? This company also enjoined receiver wars with model AA 940 (classic two channel) stereo . Must added in this competition .
admin Author
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Hi R,
While I do love Akai gear from this period, they did not take part in the Receiver Wars. The war started with the 1974 100 Watt RMS per channel Pioneer SX-1010 while the Akai AA-940 was 66 Watts per channel. Likewise I do not include the celebrated Marantz 2270. Akai actually adopted a unique market approach and instead of competing in the raw power race, Akai opted to offer quadraphonic sound in their top of the line models.
Cheers!