The Infamous Marantz Mini Stereo Boombox CH-53/CP-53

It’s been called the James Bond Marantz, the smallest hi-fi component system ever made, but when boxed in it’s flight case, it’s a portable boombox similar to the AIWA Compos or the Hitachi Lo-D units that looks great on the shelf but is also portable.

Always in the top five grails for boombox collectors worldwide, this unit is as mysterious as it is rare. No brochures or ads have been found showing the unit or the specs. The only photo of the unit for sale is an ancient photo of the Akihabara District in Tokyo circa 1980 with a price of 44,300 Yen, close to $443.00 USD in 1980 making it a fairly expensive unit.

Edit: These famous photos were originally posted by our member cassette2go years ago and they made it all the way around the internet!

Rumors have floated around that this unit was made for Marantz Japan Executives or that it was found for sale in airport flight lounges but the photo confirms it was for sale at the retail level as well.

Over the last 10 years I’ve found units for sale worldwide; I’ve chased units in Canada, South America, Japan and Thailand, sometimes they also turn up in the US. Past members that have owned these include ARKAY
http://audiokarma.org/forums/index.php?threads/got-the-most-unusual-marantz-ive-ever-seen.128675/

HIFI Tom had two units he posted on S2G around 2008 and I think someone in California had the entire set with box, owner’s and service manual.
http://www.stereo2go.com/topic/index.php?content_oid=372703924766363709&board_oid=193392314111653340

The units were made in Japan sometime around 1980, which was a tumultuous time for Marantz. Superscope, the owner of Marantz, based in Chatsworth California, was running into financial trouble and sold rights to the Marantz Name and Distribution to three different entities. Marantz Japan was one of the semiautonomous branches handling Asia and also doing most of the manufacturing of the boomboxes and stereo components and it was left largely intact. I recently talked with a director of development for Marantz USA in the 70’s and he had no knowledge of the MS-53 Units.

https://www.whathifi.com/news/60-years-marantz-are-all-about-music

Edit....Museum of Magnetic Sound Recording has a great history, read the comments from one of the 70's design engineers.

http://museumofmagneticsoundrecording.org/ManufacturersSony.html

The basic unit is an amplifier, a tuner, two speakers and either a tape deck or an equalizer. The tape deck is a walkman-style unit that could also be separated from the entire unit. The rest of the unit is powered by a 13.5 volt, very heavy, wall wart.



These units were not meant to be separated, the speakers have their own power supply and, with the exception of the tape deck, the components have a ribbon cable connecting them making them useless on their own. Everything is connected together by a somewhat complicated plug-in power system using the wall-wart.

I own three of the systems, while the basic system is the same, the name and part numbers on the units is different. I have a Marantz System that seems to be made for USA, a Unix/Marantz System that seems to be made for Asia and another Marantz System with Unix Part Numbers that I believe was one of the prototypes. I’m missing two accessories, a stereo microphone for the tape deck walkman and the Unix Branded Handle, I also don’t have the paper versions of the manuals.

More coming......

Disclaimer: Since there is no definitive source of information on these units I’m going by observations and previous posts and information pulled off the internet. Some of my information may be wrong, if you have information on these units please contribute.

 

The system is usually either of two units known as the Marantz MS-53 or the UNIX UMS-5 pencompo, I haven't found out what "pencompo" means yet. The UNIX Name was used in Japan by Marantz and was put on their boomboxes and this little system, they were labeled "UNIX" on the front with a "made by Marantz" on the back, very similar to Superscope Units that had the same "made by Marantz" on the back.

Marantz/UNIX Boomboxes are very rare outside of Japan and I believe it was due to copyright infringement. Another rumor is that Marantz sold the name "UNIX" in the early 80's for big dollars and it only shows up on units from 1980 to mid-80's. Marantz/UNIX Boomboxes go for pretty good money but the personal cassette players go for several hundred US Dollars when they do show up for sale.

The system came in two separate boxes, one holding the speakers and power supply and the other had the tuner and amplifier. Unfortunately I haven't found photos of the stand or flight case boxed up.

 

I borrowed this photo from another site; the poster used to be a proficient S2G Poster that always had great advice and kind words.

He found one of the units with the UNIX stand that holds it all together, this would have been similar to the flight case. I think the retail photo from Akihabara above shows the units with the stand but the photo is not that clear. The interesting part is the components on the photo below have a Marantz Label with this UNIX Stand, the branding is never mixed except for the label on the back always says manufactured by Marantz. When I get around to posting the actual units you'll see that the UNIX Units have a blue strip on the bottom (as seen in the photo above). I think all of the systems had a Marantz Antenna, I haven't seen a UNIX Branded Antenna and the Akihabara Photo has one antenna in the middle that looks like it says "Marantz" but it's really hard to see. (edit-the boxed units have a "UNIX" Branded Antenna Drawing)

I don't know what the black cassette-size box is to the left of the components, they are also on the Akihabara Units. You can also see the Akihabara Set on the left has a tape player while the other units just look like an amp, tuner and speaker.

 

The form of the units seems to be based on the personal tape deck, the units are all identical in size. I've found three versions of Marantz or Unix Branded Tape Players that may have gone with this system of which I own two, the Marantz CP-53 which came with the Marantz Branded System. I don't know which tape deck went with the UNIX System but I was told it was the PC-30 (non-recording), mine has "strange" branding on it making me think it was the prototype. And then there is the UNIX PC-36 Personal Cassette Player which is a mirror image of the Marantz CP-53. I feel like the UNIX PC-36 would have been a better fit since it had recording ability.

The cool thing is all the tape decks mentioned above broadcast an FM signal so there's no need to physically hook the decks to the main system. There's a lot of features on these decks that are not found on other tape decks (that I know of). It will be cool to get your opinion A O when I post more photos of the tape deck.

I think HiFi Tom had two, I seem to remember some cat-fights between members that didn't believe one member should have two of these systems but it was more around 2008 that this system was first posted. HiFi might have been with Arkay when he found his in Hong Kong.

If someone could identify the boxes in the top photo and date of manufacture we might be able to figure out a timeline, there might be some other bombshells in this thread.

 

Here's the back of the of the UNIX Unit, this is on Reli's Site but I own the unit. This is the unit in the flight case. The UNIX Part Numbers are different than the Marantz Branded Units and there is a serial number underneath each unit. The tuner on the top, UST-5 is powered by the ribbon cable, the bottom unit, the UEQ-5 Equalizer, has a plug for power and a 9v battery box. There is no cover for the battery box and I can't remember what it's for, maybe lights on the unit?

While the optional tape deck broadcasts on the FM band, there are still in and out jacks for it on the amplifier. The tape deck has an interesting mixing feature that I haven't explored yet but I'm thinking you could DJ with this unit as the tape deck has dual microphone inputs and dual headphone outputs.

These units are the same height as the tape deck, around 1" tall. There is a screw missing from the GND hole that my other units have. The gray is plastic but the top, face plate and chassis are metal. The tape deck is 100% metal except for the battery door.

 

Thanks for checking out the thread! These micro systems are pretty amazing, a lot of thought went into them and it was a ominous time for Marantz. Luckily these don't seem to have anything in common with the Phillips/Marantz mass-marketed junk that came out in the 80's (yes, there were a few exceptions). One of my theories is that these are reconfigured car audio units, hence the 13.5 voltage requirement but that might be a longshot.

The amp is in the middle marked USC-5, it's ribbon cable is fixed while the top tuner is the UST-5 and the cable is removeable. The tuner has to be above the amp due to the orientation of the cable. Someone at Marantz wanted these two units separated but it's more cosmetic since I can't use the tuner as a stand-alone unit. You could use the amp and speakers as a stand alone unit with an accessory like a turntable. Behind the ribbon cable that connects the bottom EQ UEQ-5 and the amp is another 13.5v input connection.

The EQ can be powered by the ribbon cable, it is removable on both units, I don't know what the other two power connections are for. I don't think they are in the manual as that has only the amp and tuner on the cover. The EQ was supposedly sold as an option and the amp does not need it to work.

My guess is Marantz wanted the flexibility to use the EQ with the portable tape deck. I'm not sure what the audio path would be but there is a "mixing" button on the tape player, along with some other goodies. One of the output jacks goes to the speakers, it splits into two jacks, one for each speaker.

Power for the unit is either the very heavy 13.5v wall wart, it's a little complicated and would be very difficult to figure out if you found this system with out it. It goes from wall to speaker to speaker to main system. The unit is portable using the optional flight case which has a battery tray built in the back.

 

The speakers for the Marantz 53 and the UNIX UMS-5 are very interesting little units. The Marantz Speakers are model number LS-53 and the UNIX Speakers are ULS-5, I believe the 5 is the wattage and the 3 is the number of components. With 4 ohms and 5 watts, these have all-metal enclosures held together with four screws that compresses the body to back panel and front panel. I checked a bunch of my boomboxes and none of them have metal enclosures, the more heavy duty units have plywood or pressboard, the traditional materials you would associate with stereo equipment. I think I have some Realistic Minimus Speaker from the early 80's that are metal but they are the exception.

The rear panel has four connection points, 13.5 volts in and out and amp and direct in. The power jacks are part of the complicated power system that goes from speaker to speaker to the amp. These speakers tend to show up in Japan on their own which makes me think that they were also used for other portable equipment.

These are the only photos I've ever seen of the interiors of the speakers. There is also three pieces of insulation covering the speaker that I didn't show. I'm sure vibration was a big concern so they used gaskets on both the front and back panels. The four mounting bolts are inside of black PVC flexible tubing and the rear circuit board is encased with glue holding it to the back panel (it is also screwed in).

Some of the more observant might notice the FOUR speaker wires, it's actually just two with two wires going to a light under the speaker. Marantz Branded Speakers have a red light and UNIX Speakers have a green light.

You can see by the build of these enclosures that a lot of thought went into them, these are not off the shelf components, the panels have pins so the gaskets don't move and the gaskets themselves are made just for these units. You can see in the photos how nice the parts fit together with that perfectly fit gasket. Almost all of my speakers have a stickered serial number, only one set is identical all the others are different numbers.

 

My engineering knowledge doesn't cover the recessed holes on the back panel. I feel like they were for a jig to nest and assemble the units but the odd thing is the Marantz Unit has two extra reliefs on the top edge. I haven't opened any other speakers and don't really want to unless they quit working but does anybody with more manufacturing experience know why these would be different? You can see by the last photo how nicely everything looks, reading the comments left by "Paul" on Museumofmagneticsoundrecording.org (posted above) makes me think that the Tushinskys Brothers had a hand in developing these...

"Customers could be assured that their Marantz product would draw attention to itself, visually as well as audibly."

"Many of us in the Product Development area were pushing for technological innovations. Fred Tushinsky generally resisted those. He was willing to compete on performance specifications, but he preferred to focus on the outward, superficial appearance of the product. I remember a product meeting once with Fred where we were looking at the new offerings from competitor Yamaha. The Yamaha receiver looked like a piece of jewelry, and Fred was determined to out-do Yamaha in that department"

In 1980 the AIWA Compo and Toshiba Aurex were the "little" stereo units to beat, I have to believe Superscope wanted something better. At the time Marantz was developing a player piano that used a cassette deck for input, so nothing is off the table.

 

And just to add more folklore to the subject I've got some links to the UNIX Name. These days it's a computer system that might have been started by AT&T. According to this article the "Open Group" now owns world-wide rights to the name.
http://web.deu.edu.tr/berent/unix/otherunix.html

This is much more interesting from Computerworld 4/9/84, where Marantz Japan claims the name was stolen from their 1962 registered trademark for it's radio cassette recorder they developed in 1962. What entity of Marantz developed this? (page 23)
https://books.google.com/books?id=mt0cw1-3PIkC&pg=PA23&lpg=PA23&dq=unix+trademark,+marantz+japan&source=bl&ots=bIV9XfeSyJ&sig=RBH2Gi9ixqggM1BE5YtssTkybRQ&hl=en&sa=X&ved=0ahUKEwiCtKvw0IHaAhWCr4MKHbEEBk4Q6AEIMjAC#v=onepage&q=unix trademark, marantz japan&f=false

And a more current article from 2003 where they are still fighting over the UNIX Name
http://www.zdnet.com/article/who-really-owns-unix/

Somewhere I've read that Marantz received millions to give up the UNIX Name, AT&T pretty much owned telephone service so they had big enough pocket books to buy the copyright but I haven't found that information yet. UNIX Boomboxes and Portable Tape Players go for big dollars on Japanese Sites so don't underestimate the quality. I've got another thread comparing some small Sansui boxes to Marantz/UNIX and they are the same boxes. My small collection of Sansui Boxes are heavy even though they are small (heavy = quality to me : )

 

Ok, now for some of the good stuff, the Marantz CP-53 Portable Stereo Cassette Recorder and the Marantz/Unix PC-30 Stereo Cassette Player (that I own). From all the internet information I've read on these units, it either came with just the amp, tuner and speakers or you could buy the cassette deck or EQ as an option ( 3 components x 5 watts + 53?). The Marantz System is easy, it had the CP-53 Stereo Cassette Player as an option, this is the only known Marantz "walkman" type player I know of. Yes there's the Superscope/Marantz Line of PMD or CD "field recorders" and these are top notch but this is a traditional style player similar to a Sony Walkman and about 1/4 the size of the PMD/CD Units.

I'm not an expert but I've never seen the Marantz CP-53 for sale outside of being bundled with the Marantz MS System. There is really no literature or ads on-line, if you have some please post! The UNIX System was a little more obtainable, at least in Japan, they had the PC-30 and the PC-36 and I think they were the first generation Marantz Walkman Style Players, I posted a few more models in the walkman area below.

The UNIX PC-36 is identical to the Marantz CP-53 except that the Marantz is gold and the UNIX is silver. I don't own the UNIX PC-36 and I'm going by photos I've seen but I do own a PC-30 (which is branded Marantz).

So if your really confused I'll post my photo; the Marantz and Unix Portable Cassette Players are extremely rare. PC-30 is normally associated with UNIX Branding but mine has a Marantz Tag on it, I'll get to that later but when these do show up they have UNIX Branding. I bought the only CP-53 I've seen for sale in the last 15+ years (with a full system) but there were at least two members on the old forum that also had the set with the tape deck.

 

As you can see, the case is exactly the same but there are some small differences. The biggest is the recording feature on the Marantz CP-53 but the UNIX/Marantz PC-30 is also missing the tape counter and a "hot shoe" for the stereo microphone. Of course the PC-30 doesn't record so it doesn't need the microphone. The UNIX PC-36 would be equal to the Marantz CP-53 but I was sold the Marantz Branded PC-30 as the cassette deck for the UNIX Micro System Pencompo that I own.

Here's some photos of a recent overseas auction of a PC-36, this one went for close to $100.00 USD, a steal for a Marantz or UNIX Portable Cassette Player, they seem to hover around the $300.00 USD Range. These units are all metal and heavy, some of the buttons are plastic but these were very well built. I think the last numbers on the sticker indicate the serial number, It wouldn't surprise me if they made less than 400 of these players.

I know AO is going to ask what that little sticker and hole is on the left side panel, it's for a threaded antenna. The sticker has two arrows and the other hole on the control right side is also threaded so they had an antenna which needed two connection points. Now ARKAY is going to step in and say "but there is no radio." and he's correct, I think the antenna is to broadcast your tape player to the micro system (or receiver that can get 87-90 MHZ). I don't have the proper antenna and have never seen one, the system comes with rabbit ears but they hook directly to the tuner.

Some of the more observant will notice the "STEREO MIXING/ON AIR" labels, truly unique for a small cassette player, and yes the Velcro is part of the player.

 

So I just noticed that the UNIX PC-36 and My PC-30 broadcasts on the 77-78 MHz band and the Marantz CP-53 broadcasts on the 87-90 MHz band which might confirm that the UNIX was only meant for the Japanese Domestic Market and the Marantz was for North America (our FM starts at 80 MHz). I don't know what the European Bands are, maybe someone can help?

 

Now's your chance to own one, this tasty unit just came up for sale. Unfortunately with these systems it seems like you either get the ultra-rare box (with EQ) or the ultra rare cassette player (without box). This one has no cassette player.

This unit does have aftermarket connections, notice the wye connection at the speaker output jack which might hamper other connections. They are not showing the 13.5 volt wall wart, meaning you will have to power this with batteries only until you find the proper transformer. It looks like it's also missing the ultra-cool antenna that should be nested in the back cover with the batteries.

https://www.ebay.com/itm/RARE-VINTA...142581?hash=item4b40d36375:g:DwYAAOSwjzJa07II

 

This UNIX Unit is fresh off a Japanese Auction and includes the UNIX PC-36 Personal Tape Player. While the components look a little roached out, it does seem to include most of the cables and the antenna. This might be a true UNIX Antenna since it looks different with it's white, maybe gold, base, unfortunately there is not a good photo of it. Bidding was fast and furious on this as the auction site adds five minutes if the bid is near the closing time. It eventually went for a staggering $368.94 USD before adding in shipping. If the buyer reads this please post more photos of the antenna.

 

So I forgot that S2G still had a Facebook Page, I was looking for something and this beautiful photo showed up from yesterday. Barbosa Ricardo posted Marantz Gold, never seen before in the box CP-53 and EQ-53. Drool while you can, hopefully he's on this site as well. So he found the very rare EQ-53 but there's a box of the CP-53 showing headphones with a microphone helping to explain the on-air mixing function of the tape player. The original box also shows the super rare mic that plugs directly into the player. and mentions a carrying case.

Of course we get "Not a big fan of Marantz" from the posting, unfortunately he doesn't know what he has......