RCVR: Harman Kardon 900+ Quadraphonic Receiver

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Quadrockasaurus

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If you have any more photo's or comments to make on this Quadraphonic unit please feel free to post them in this thread....:)

Harman Kardon 900+ Quadraphonic Receiver

Rarity: RARE
Average Sale Price: UNKNOWN

Harman Kardon 900+ Quad Receiver.jpg

Top of the line in the Harman Kardon Quad receiver range in the early to mid 70's just above the 800+. The 900+ looks mostly identical to the successor/predecessor unit (Model 150+) with a few visual differences...i.e. tuning dial went from a three color combo on the 900+ to just green. (...not sure which unit replaced which..??:confused:). The 900+ was also OEM-ed/rebadged as the "Williamsons Model 128" Quad Receiver.

The 900+ has an onboard SQ decoder and CD4......don't have too much more info on this particular unit.

The 150+ units appear to be much more common than the scarce 900+.
 
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Disclord

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Does any QQ member prefer the "Joystick" approach to quad soundfield control? I do not - I can't ever get the setting to where it's "perfect" for every channel, and the ones I've seen seem to get dirty/noisy very easy, which leads to audio drop outs in some positions, etc... kinda like the cheap, unsealed front panel knobs in the Fosgate Tate II 101A: Television Tuner Cleaner spray is the 101A's best friend! I assume the earlier Fosgate Tate 101 Tetrasound has the same cheap controls too - it certainly looks like it does, the later 101A being a virtual clone of it.

Thanks for posting the picture - I LOVE looking at pictures of quad gear.
 

timbre4

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I lusted for a 900+ back in the day (1974), did manage to later (2000) find a 150+ on eBay that I enjoyed very much until a channel went out. If memory serves, I believe I later sold that receiver to Lou Dorren!

Next to the 150+ was the 44+ CD-4 demodulator and 8+ quad cartridge player. Coupled to some Advent speakers, Houses Of The Holy sounded like 1973 all over again.

If I find pictures I will post.
 

Doug G.

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Yup, a true beauty!

Ah, Houses of the Holy. I will play it today on my system which, coincidently, has stacked Advents in each corner.

EDIT: I think the 150+ was earlier because it seems they were around in the very early seventies and the 900+ was a little later. More towards the mid seventies.

Doug
 

Disclord

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I can't tell from the picture if any of the buttons are labeled as such, but did the built-in SQ decoder have any form of Logic, either Full Wave-Matching w/Front-Back (or F/B alone) or Full Logic with F/B Vari-Blend? It seems that the date the HK 900+ was retailed would put it in the "logic available" category, either discrete circuits or the Motorola/Fairchild Full-Logic IC set. (The number of Logic sets and the combinations that CBS made available was so insane - a "make-it-up-as-you-go-along" approach, which SQ [and to a lesser extent, QS] really was!)

As a side note regarding SQ Logic, it's too bad Sony never produced their own patented signal cancellation decoder - it was a true Parametric SQ decoder using Selective Cancellation like Vario-Matrix, Shadow Vector, Paramatrix and the Tate I/II DES; Sony had a QS version too - I've never been able to find out if either was sold in the Japanese market or not. Apparently, from what I've been told, Sony made high precision, and relatively low-cost, all-pass phase shifters for SQ and OEM'd them to other companies - Martin Willcocks told me they used Sony's 8-Pole phase shifters in the SQ decoder boards they sold to Audionics (the non-logic 'High Resolution' SQ unit) and in the first few designs of Willcocks prototype Tate DES decoders. The Fosgate Tate II 101A uses Sony's 6-Pole design (just the design and not an actual Sony-made board) and Audionics Space & Image Composer used the 8-Pole design.
 

Quadrockasaurus

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I've never had a unit with a joystick but I always assumed the locator/stick was pretty handy if you had a large room and regularly listened in different locations in that room and just HAD to have the soundfield perfect no matter where you were...

I wish I had more info on the 900...You'd think after so many years there would be some more info on this unit somewhere on the web....but there is very little, I got all the decoders info I have from the HK800+ ad Jon posted earlier in the Hardware section (..I'm assuming here that the top line 900+ would be equipped with the same decoders as the 800+)...I can barely make out the blurry details on the image I have...
 
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Quad Linda

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This is a nice piece. I'm working from memory on this, so forgive me if I'm a bit off on spec's. I sold a lot of H/K in the day, owned two cassette decks and some Citation gear. I considered buying a 900+, but never did. Sold a few, though. First, here's what's great about this piece: Ultrawideband-an amplifier that is capable of producing a wider frequency response than we can hear. Why? It is smoother and more responsive in the audible range. It has a faster "switching time" than most Quad pieces, adding to realism. These are the biggest reasons H/K sounds so good. Great features like an early version of 2-Zone operation. Connect tape 1 out to tape 1 in, and you can run it as two systems (stereo only) with separate sources: any source on Z1 (front amps) and tape 2 on Z2 (rear amps.) Separate bass, mid and treble controls for front & rear.

What leaves something to be desired:
The joystick is the biggest drawback. It's almost impossible to balance with these things. They look cool, but tend to be "all or nothing" controls. The joystick was the deal breaker in why I never bought a 900+. Individual knobs or linear pots work way better. Power isn't very high. I don't recall the power ratings, but I recall perhaps 30-40x4? I know the 800+ was 22x4. Since power is logarithmic, 40W is slightly higher than 20W, 3db to be exact. Yet, there is double the headroom. I recall that it was less than full logic for SQ (front-back logic only?) In pushing the limits of performance, reliability is sometimes compromised. H/K gear of this era isn't as reliable as some of it's competitors with lesser performance. It's the reason I sold off my H/K Citation gear. I still own a CD-401 3-head H/K cassette. Like Marantz pieces of this era, tuner sensitivity is not great. With an outdoor FM antenna or proximity to FM transmitters, FM will sound better than most receivers. CD-4, stereo LP's and Q4's will likely sound better through this than most other Quad receivers. The added bandwith will add immediacy to full frequency sources.

Sorry if I offended any H/K users. In light of everything I said, I believe that this is a terriffic sounding quad receiver, one of the best. Just be aware of it's strengths and weaknesses. It has simple lines and great styling.

Linda

I've never had a unit with a joystick but I always assumed the locator/stick was pretty handy if you had a large room and regularly listened in different locations in that room and just HAD to have the soundfield perfect no matter where you were...

I wish I had more info on the 900...You'd think after so many years there would be some more info on this unit somewhere on the web....but there is very little, I got all the decoders info I have from the HK800+ ad Jon posted earlier in the Hardware section (..I'm assuming here that the top line 900+ would be equipped with the same decoders as the 800+)...I can barely make out the blurry details on the image I have...
 

4morhktech

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I am a former customer service technician for H/K. I was with H/K from January 1974 to October 1988. I'm very familiar with the 900+ receiver. For about 12 years I was the only technician working on all multi-channel receivers at H/K's in-house customer service department first in Plainview, then Woodbury, NY. I know all of the weaknesses of all those "plus" models. I don't know exactly how many I worked on in total, but it had to be in the high hundreds, if not thousands. In other words, I probably had my hands on more 900+ units than any other individual technician in the world.

The 900+ (and the 100+ & 150+) was designed by H/K in the USA but custom manufactured exclusively for H/K by a company named "Crown Radio Company" in Japan, not to be confused with a similarly named American company based in Indiana. I understand that the 900+ had appeared a few years later in some foreign countries (South America?) as a counterfeit after it was discontinued by H/K, perhaps relabeled. I'd be curious seeing one relabeled... could be a collectors item.

The 900+ was basically an upgraded 150+ with slightly larger power transformers (TS-464 & TS-465 replacing the TS-436 & TS-436A transformers), a multi-color dial scale (replacing the green), and a CD-4 decoder built in replacing the phono preamp. On the 900+, the CD-4 board has the magnetic phono preamp stage. Also, the 900+ came standard with a wooden top (and side) cover. The 150+ had an optional wooden cabinet but came standard with a metal top cover.

In quad mode, each channel in the 900+ could easily deliver 45 Watts per channel into 8 ohms. In stereo bridge mode, it was rated at 90 Watts a channel in 8 ohms but easily did more. Over 100 Watts per channel stereo into 8 ohms was typical. Power output ratings on H/K products were always at the time very conservative.

Each of the 4 amplifier modules were the same circuit design (but not the same components, however) as the then top-of-the-line Citation 12 amplifier. However, the Citation 12 was produced in Plainview, NY with US-sourced components.

The 900+ was plagued with noise (hiss) at minimum volume as the 2SC458 tone board transistors aged. In customer service, I later replaced all 2SC458s on the tone board with Motorola substitutes (with a 43025972 H/K in-house part number) to prevent recurrence of the noise. Also, the tone board was a double-sided board with feedthroughs from one side to the other. Those feedthroughs were notorious for failing, or becoming intermittent, requiring re-soldering. I used to re-solder all as a precautionary measure. Gaining access to anything, especially the tone board, was tricky if you were unfamiliar with it's dis-assembly. Repairing the output boards was mostly impossible without removal. I used to remove defective output boards and rebuild them outside the receiver. I had a stash of rebuilt boards to replace the defective ones and then devoted a couple days to rebuilding a bunch so I could just replace a defective board with a rebuilt board assembly. Brand new output board assemblies were never available. Each output board was identical but had different lead lengths and therefore were coded with numbers 1,2,3 & 4 to indicate installation location.

As for the joystick, if everything is working correctly in the 900+, each channel will be equal in level and the joystick would be fine in dead-center. I thought the joystick idea to be quite ingenious. I don't know why anyone would have a problem with it.

I'm not sure anyone would be interested in any of this information but it's been stored in my brain for many years and I'm happy to share rather than taking it to my grave, for anyone interested. I wonder how many 900+ receivers still exist on this side of a landfill.

As for the 75+ and 800+, they were also designed by the H/K engineering team in the USA, but were custom manufactured by another company in Japan, not Crown.

I currently own a 75+, an 800+, and a 900+, none are currently being used and not for sale. All were acquired by me long after leaving H/K.

By the way, the 900+ pictured above has the incorrect tuning knob. The 900+ tuning knob was black. It looks like the one pictured came from a model 150+.
 

quadsearcher

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4morhktech, I'd be interested to know what the Motorola number was for the 43025972. I had a lot of noisy 2SC458s in an Akai quad 8track and replacing with a similar newer one (don't know the number offhand) helped, but not enough. Some day I plan to try all metal film to replace the carbon comp resistors (after replacing all caps for longevity) and see if that helps. If there was a known low-noise C458/ 123AP replacement I would get a bunch to keep on hand.
Good information, thanks for sharing.
 

4morhktech

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4morhktech, I'd be interested to know what the Motorola number was for the 43025972. I had a lot of noisy 2SC458s in an Akai quad 8track and replacing with a similar newer one (don't know the number offhand) helped, but not enough. Some day I plan to try all metal film to replace the carbon comp resistors (after replacing all caps for longevity) and see if that helps. If there was a known low-noise C458/ 123AP replacement I would get a bunch to keep on hand.
Good information, thanks for sharing.
It was a 2N3417, IIRC. They were general purpose devices used in a myriad of H/K products produced from the late 1960s into the late 1970s. They are not necessarily the lowest noise transistors available but they are magnitudes quieter than an aging 2SC458. And their reliability is high, they don't get worse with age. On the tone board of the 900+ they were fine. Be advised that the lead configuration is different than the 2SC458. The 2SC458 is ECB (when viewed from the beveled edge as the front, leads pointing down). The 2N3417 is EBC (when viewed from the flat part, leads pointing down). H/K bought the house-numbered 2N3417 in batches of at least 50,000. Not all were sourced from Motorola, however. Some came from National Semiconductor. They were fine too.
 

4morhktech

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Yup, a true beauty!

Ah, Houses of the Holy. I will play it today on my system which, coincidently, has stacked Advents in each corner.

EDIT: I think the 150+ was earlier because it seems they were around in the very early seventies and the 900+ was a little later. More towards the mid seventies.

Doug
Yup, the 150+ came out in 1972 and was discontinued in late 1974. The 900+ came out in 1973 and was discontinued in late 1975. There was an overlap when both models were being produced. The 900+ did not really replace the 150+. All remaining H/K quad models were discontinued due to lack of software support in late 1975... insufficient numbers of recordings were produced by the major record labels to support 4-channel hardware sales. As a matter of fact, H/K was supposed to come out with another quad receiver, the 700+. The 700+ was first destined to be built in Puerto Rico, then that changed to Plainview, NY. Production of the 700+ was canceled before it started (only a handful of pre-production prototypes were built). Some of the inventory of parts purchased for the 700+ was used to build the TA-600 stereo receiver in 1976 in Plainview. At the time, the TA-600 competed in a similar power/price range as the Japanese-produced model HK730. The TA-600 was conservatively rated 38W/chan while the 730 was 45W/chan. A great number of the US-made TA-600s were exported to European dealers because US-made products were hot ticket items there at the time. There are (or were) probably more TA-600s in Europe than the USA. Perhaps as many as 2000 TA-600s were actually produced. Not all of the 700+ parts were used up for production of the TA-600.
 

timbre4

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4morhktech - a HUGE thank you and QQ welcome to you! A big smile on my face reading your detailed first hand accounts about the HK quad receivers. It is holy grail stuff IMHO.

As to the joystick for balancing, this was the most ingenius solution to control/adjust a quad soundfield IMHO. It simplified several decisions or adjustments into a single intuitive move. My first quad system was the 1972 Panasonic receiver and Q8 deck with the quad joystick balancer on a 20 ft cable. Using that was a lot of fun as you could solo out channels and concentrate on certain elements of the mix. That was an integral part to my quad listening fun and I missed it a lot with later gear. One day I may have one for my Marantz 4140 without taking a mortgage to get one.

HK questions:
1. Any idea why there was not an integrated quad amp issued? (if there was I'm not aware)
2. Do you have any insights as to the HK 8+ quad cartridge deck? It was my favorite.

Thanks again for joining our site. :)
 

8trackman

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I'm not sure anyone would be interested in any of this information but it's been stored in my brain for many years and I'm happy to share rather than taking it to my grave, for anyone interested. I wonder how many 900+ receivers still exist on this side of a landfill.
I am interested, and I am glad that you are sharing this information with us, although I don't really understand all the technical details, the H/K 900+ was the first piece of quadraphonic equipment I had ever seen, and is partly why I am into Quad...never saw a receiver with a joy stick before......that's when my journey began lol
 
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8trackman

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As to the joystick for balancing, this was the most ingenius solution to control/adjust a quad soundfield IMHO. It simplified several decisions or adjustments into a single intuitive move. My first quad system was the 1972 Panasonic receiver and Q8 deck with the quad joystick balancer on a 20 ft cable. Using that was a lot of fun as you could solo out channels and concentrate on certain elements of the mix. That was an integral part to my quad listening fun and I missed it a lot with later gear. One day I may have one for my Marantz 4140 without taking a mortgage to get one.
I agree the remote is fun!.....sounds like I have the same system now that you did in 1972, I have all Technics/Panasonic gear.... haven't tried playing any quad vinyl yet buts its great for 8 tracks
 

timbre4

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You probably have REAL gear if Technics is involved! I had the very first (quite hissy) RE7750 receiver and RS 845US Q8 deck with the balancer. Nonetheless it brought me much joy when I was 14.
 

4morhktech

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4morhktech - a HUGE thank you and QQ welcome to you! A big smile on my face reading your detailed first hand accounts about the HK quad receivers. It is holy grail stuff IMHO.

As to the joystick for balancing, this was the most ingenius solution to control/adjust a quad soundfield IMHO. It simplified several decisions or adjustments into a single intuitive move. My first quad system was the 1972 Panasonic receiver and Q8 deck with the quad joystick balancer on a 20 ft cable. Using that was a lot of fun as you could solo out channels and concentrate on certain elements of the mix. That was an integral part to my quad listening fun and I missed it a lot with later gear. One day I may have one for my Marantz 4140 without taking a mortgage to get one.

HK questions:
1. Any idea why there was not an integrated quad amp issued? (if there was I'm not aware)
2. Do you have any insights as to the HK 8+ quad cartridge deck? It was my favorite.

Thanks again for joining our site. :)
1. I had nothing to do with marketing so the answer is just a guess on my part. Bear in mind that a receiver is nothing more than an integrated amplifier with an AM/FM tuner built in. At that time most customers opted for a receiver than an integrated amplifier. Since they marketed a series of quad receivers, why build one minus the AM/FM tuner? It probably would have been a sales dud just like the few integrated 2 channel amplifiers from that time period. Remember that marketing wants to concentrate on products that the majority of people want to buy.

2. I did not work on any tape equipment at H/K so my experience was limited to receivers, amplifiers, tuners, and preamps. There were other techs that specialized in tape products. I knew of the 8+ but never used one. I don't think the 8+ was a very popular product.
 

Quadrockasaurus

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4morhktech....another big thanks for taking the time to give us all this useful info on the 900+ (...and related) Quad units....(y):)

I'm assuming then, by the info that you've given, that the "Williamsons Model 128" receiver I listed in my original post is one of those "after the fact" counterfeit 900+ units you mentioned...and not the real McCoy.

FYI - found that info in an obscure post/thread in Audiokarma from a AK member in (..I think) Hong Kong.

Cheers.
 

4morhktech

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4morhktech....another big thanks for taking the time to give us all this useful info on the 900+ (...and related) Quad units....(y):)

I'm assuming then, by the info that you've given, that the "Williamsons Model 128" receiver I listed in my original post is one of those "after the fact" counterfeit 900+ units you mentioned...and not the real McCoy.

FYI - found that info in an obscure post/thread in Audiokarma from a AK member in (..I think) Hong Kong.

Cheers.
I posted a followup to that topic on AK last evening. Those relabeled 900+ are most likely from that batch of overproduced units from Crown. I would love to see a photo of the front and back (and anything else) of any relabeled 900+. Crown had taken the liberty of producing more product than ordered assuming they would be ahead of schedule on the next batch. H/K canceled the order for more units and Crown was left with a sh*tload of unsold product. First, H/K labeled 900+ started showing up for servicing at warranty stations without US installed modifications (to the CD-4 board), then lots of orders came in for owners manuals (that were typically packaged with the 900+ in Plainview, NY). This raised a red flag about the unauthorized units. One of the warranty stations shipped a counterfeit to the National Service Manager for evaluation and a notice was sent to all warranty stations to disallow warranty claims on the counterfeit units. The National Service Manager advised me to bring any to his attention brought in to H/K that slipped through the cracks in the receiving department. I saw a few suspects over the years (with H/K labeling) but it was a non-issue because they were repaired out-of-warranty. H/K was primarily interested in not having to pay warranty stations for repair of non-authorized units. From what I heard at the time, Crown was in bankruptcy, and the trail from trading company to trading company in Asia made litigation over it very difficult and the issue was mostly forgotten. All of the H/K personnel knowledgeable about the situation gradually left H/K or passed away, so by now you won't find a single currently employed Harman employee even aware of it today, or even care this long afterward. It only lives on here in discussion forums. But I have always wondered what happened to the bulk of the counterfeits. Now the puzzle is coming together for me.

Other than the fact that the counterfeits were not produced under H/K's authority or that H/K made a single dime from them, the counterfeits should be every bit the same as those sold legally under the H/K brand, with the exception that they don't have the small CD-4 modification board added to the CD-4 circuit. They were, after all, produced in the same Japanese factory as the legit units. However, the re-branded units may have additional changes that I'm not aware of.
 
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Quadrockasaurus

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As a matter of fact, H/K was supposed to come out with another quad receiver, the 700+. The 700+ was first destined to be built in Puerto Rico, then that changed to Plainview, NY. Production of the 700+ was canceled before it started (only a handful of pre-production prototypes were built).
Just curious....

....did any of the prototype 700+ units survive...?? Do any images exist..or brochures printed??. It sounds like that unit got pretty close to production, and I've noticed that with some other brands (..Astrocom, CM Labs, Marantz..etc) brochures were printed, or magazine images exist for stuff that ended up ultimately not being produced....
 
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