Sony DD portables genealogy

Updated table: Dec. 31 '22, D6 to ZX-7 (potted servo module), added Panasonic direct drive models (lots of attributes missing), DD30-DD33 bass expansion and servo IC fix, uploaded a PDF copy, TC-D3 and TC-D6C alternative model numbers added, DD11-DD22 motor and servo IC fix, DOL abbreviation corrected.

In the overview I consolidated (objective) information about the portable devices from Sony with the disc drive (DD) mechanism in a table and timeline.
All information is collected from various forums, threads, websites and related files, and input from S2Go members!
I was inspired by a thread that depicted on a timeline a set of the DD units, plus main capabilities and release year - can't find it back though.

The DD genealogy starts with the TC-D5 and ends with the DD22.
Related portables without the DD mechanism, but otherwise influential, have been included too.
Between units I added the text accompanying the arrows. The intent is to clarify the relation between the units, based on service manuals and findings from members of this forum,

Spotted an error, information to make the overview more complete, or want to contribute in any other way? Please let me know!



Updated timeline: May. 31 '23, Copy-paste inheritance DD and F5, minor other changes, D6 to ZX-7, DD30 to DD33, DD9 to DD33, and DD33 to DD22, D6 to ZX7, aligned details for most relations, changed dashed lines to solid for all with clear relation, added auto-reverse for DX100 and DD22.

With relation details:


Clean, without details:


Contributing members: TooCooL4, Machaneus, stuck-in-time, Mister X, mihokm, Valentin, theLAG80s, JK1210, rolandd74, and CDV.

 

Sony don't make a Direct Drive portable, they make Disc Drive units.
Not many companies make a Direct Drive portable and the ones that are made can be counted on the fingers of one hand.

 

What a oversight on my behalf.. I started the file with that title and did not look back. Will make the necessary changes to the first post and attachments!
@Mister X as moderator: is the thread is better moved to Chat Area or any other location, please relocate.

Edit: I just updated the PDF file and attached the latest copy to the first post.
The 2 remaining references were changed from Direct to Disc as @TooCooL4 pointed out.
I also added values for Total Current for some units and normalised a few columns for consistency.

 

Hi Emiel ,
What a wonderful DD world map !

Obviously a lot of work and study in there , it's a bit of a cliche but really thanks for sharing .
Following your invitation , some additions and a suggestion , a small contribution to your effort for completeness .

Aditions :

- Sony WM DD-10 is missing from the list , appeared on September 1989 referencing from the date on the service manual, its predecessor was DD-1 ,
on the front of the walkman is printed the Dolby logo "DOLBY B" whereas DD-1 has "DOLBY" missing B , reason being the following :

Dolby A was a professional noise reduction system from the 60's and Dolby B designed for consumer electronics (late 60's early70's) , so there wasn't any need to call it Dolby B on any consumer product , a plain " DOLBY " logo was enough as there wasn't really any choice.
With the appearance of Dolby C in 1980 for consumer electronics and its progressive popularity there was a choice so "Dolby" logo got its full name "Dolby B".

- Sony WM-5 was something like a transition model between WM-2 and WM DD it has the internals of WM-2 and the metal skin and shape that was to become so famous with the DD series , the equivalent of Tony Stark's first suit the ... IRON walk MAN !

- In column "Battery Voltage " in subnotes you may wish to add that WM DD-9 accepts alternatively to gumstick also a normal AA type 1.5 v battery cell .

Suggestion :

- Signal to noise ratio specifications column, not keen to go too deep on that and how important it is .

I can confirm that all your information in column "Design" are absolutely correct ! ( Maybe I can provide some additional info soon. )

Keep up the good work !

PS : WM DD-9 is unique because it can accept both types of battery at the same place , although not simultaneously , without the need of an external battery adapter .

 

Thanks for your feedback @Machaneus .
First given your listed location, I hope everything is well given the recent fires and very hot days.

• I will add the WM-DD10 to the list with the attributes you mention.
  Don't know why it escaped the overview in the first place.
• Dolby A - is your recommendation to create a different value for Dolby Noise reduction for the TC-D5 family and WM-DD?
  I just looked up images and the D5 top panel also features 'Dolby System', not Dolby B as I entered. By your explanation it is in fact Dolby B, let me know what you think.
• The WM5 I do have here (although in pieces) and I consider a transition model too.
  However since the mechanism is nothing like DD as you rightfully state - it features a normal pendrive motor with belt - I decided against including it as a line item.
  I will add to the design description of the WM-DD: transition model to first feature the signature metal housing. See it as a honourable (and important) mention.
• The description of the DD9 will be updated, since the DD9 is unique in this list in terms of gumstick OR AA.
  Outside the list, the WM-EX508 features the same functionality for instance, except battery compartment access is from the outside.
• The SNR ratio specifications I would like to keep for now as I would like to see if it is possible to hide columns (user configurable) from the overview.

Thanks again, keep the info coming!
Emiel

Edit: updated the first post picture and attachment to reflect the changes.

 

You are welcome @Emiel ,

Well the fire reached areas 25 km from the center of Athens even my brothers house has suffered minor damages to the exterior of his house but thankfully everyone is safe now , at least in this area , but a lot of people lost their homes and their jobs , the nightmare though is not over , there are still fires and the danger of floods in winter is very high , I would say a certainty , there was a massive loss of forests .
By the way a BIG thanks to all European and other countries who supported and all the people who came here to help !

Your listings are just fine no need to create a different value .
Dolby A was only for studios or something never on consumer products , walkmans cassette decks etc .
Dolby and Dolby B printings are the same thing in all walkmans .
After the appearance of Dolby C in 1980 and more specifically after WM D6C appears the Dolby B printing on walkmans , I mentioned it just for clarification. (it seems I didn't succeed though )

Yes D5 's "Dolby System" printing is actually Dolby B , all is correct in your listing .

I wasn't proposing WM-5 to be on the DD line model list and you were correct to not include it but I believe it deserves , as you said , an honorable mention !

 

Not as popular or well known as the walkmans, but Sony did make at least one boombox with the Disc Drive transport, the Sony ZX-7. I don't know if they made more than one model though. They're not frequently discussed and and Sony themselves didn't seem to point out the DD in it as much as they do with other DD units.

Heres's some scans from my copy of a mid 80's catalogue

 

Thank you for sharing @stuck-in-time .
This is a great addition to the list, it for sure was marketed as a portable!
It seems that the release year is 1983, month May. See Japanese brochure link below, last page. According to HifiEngine the end of production was in 1986.

Is it a mix of an earlier boombox and the WM-D6(C) judging the Wow and Flutter values?
Looking at the power consumption - total current - though, it seems to be a TC-D5 derivative in a boombox jacket. See the first post of the thread.
Peculiar it was not promoted more, since for instance Technics did it for the full size cassette deck BX707 with both Quartz and DD on door in the early '90s.
Any additional details are welcome!

There is a brochure available over at HifiEngine (https://www.hifiengine.com/manual_library/sony/zx-7.shtml).
I can't read Japanese, but is sure has nice images and the original retail price 62800 Yen.
The close up of the front indeed clearly shows Disc Drive, and Dolby NR (not Dolby B).


Edit: updated the first post picture and attachment to reflect the changes.

 

I added a note for Dolby NR and reformatted some columns for logical grouping and representation. Trust this works.

 

Regarding Dolby printed logos ZX7 is a good example , while the photo of the boombox in the brochure shows " DOLBY NR " printed (NR for Noise Reduction) in the brochure's text a paragraph is titled "Dolby NR / B type " , from generic to specific .





This might be of interest , disc drive principle grandfather ? From a Sony portable tape recorder circa 1964 - 5 .

 

Thanks again for the reply @Machaneus .
The devices predating the TC-D5 I don't have that much information about.
I love the automated translation feature, did not think yet of using it since I can't read Japanese.
The 3rd line is indeed peculiar..

 

Thanks for sharing. There is not a lot of info on the net about the DD10, a low cost German market only player. Great to see it in a German brochure from @autoreverser .

 

Strangely enough, on the front page it looks like they featured a red DDIII, while they kept it out of the specs. If color was the reason, they could have easily swapped it for the newer DD30 in red.

 

Forgot to ask a while back: do you have a model number of this recorder?

 

A slight difference with the walkman DDs, this used a added a separate idler wheel between the motor & capstan flywheel. I don't think this type of drive was used much in tape recorders, so it's interesting to see here. It's more commonly used in older generation turntables, called an idler-drive system. I would assume that it brings the same effect of minimizing wow & flutter of a DD mechanism, with the DD working in similar way with less parts needed.

Before the Sony DD, several other brands had also made "walkmans" similar system to the DD, where the capstan has rubber disc in its flywheel. National/Panasonic had the RQ-210 and Sanyo had, among many similar models, the M-508. The main difference with the Sony DD being that they do not have an FG system to regulate the speed.

I think it would be interesting to discuss why this system is not more widely adopted. These are early mono units and I haven't found any similarly driven units to fill the gap between them and the Sony DD around a decade later. Even wit the success of the Sony DD, competitors don't seem to be copying the system.

 

Those that have a separate idler wheel between the motor and flywheel may have a motor that runs off AC. If it uses and AC motor, it must rely on a pretty big flywheel to achieve a reasonable wow&flutter.
Mains frequency is fluctuating all the time, so a constant motor speed is hard to achieve. Instead, those units have a relatively loose rubber belt in order to "decouple" the motor speed variations from the flywheel.

In regard to why the DD system was not used more widely, one of the reasons may have been cost: both BOM cost and R&D cost. These units need special customized mechanical parts like flywheel, custom rubber, a custom motor, but also custom electronics such as an FG coil and a custom servo IC.
SONY designed the ICs themselves, so it wasn't a big deal if they were to mass produce a unit like this, but most other brands used off-the-shelf ICs from Sanyo, Toshiba, JRC and others because the R&D cost was too high.
Don't know about the mechanics, but judging by the big differences between SONY mechanisms and other brands, to me it seems those were designed in-house by SONY as well.

As a sidenote, SONY are still making their custom chips today in almost all products ranging from the PlayStation to photo cameras, video cameras, DAPs, noise cancelling headphones, etc.

 

Well observed @stuck-in-time , the idler drive system was used vastly in older record players , these were simple devices that usually you could carry around , they had a speaker , a small audio amplifier and run on batteries and /or mains , and as far as this topic is concerned , had a DC motor because there were as many varieties as you can think of .
Turntables on the other hand is a different species with specifications closer to that mentioned by @Valentin .

50 years ago as a young a boy I had such a record player , it was a perfectly working Philips but I was curious , I had to open it !
Now the idler didn't really surprise me it was kind of obvious , I thought it was clever the way the record speed changed from 33/45/78 with the stepped point of the motor.
What puzzled me was the motors structure , it was not like the Mabuchis on my electric toy cars !
Several years passed until I realized that this motor had a mechanism to keep its speed constant , it was a simple centrifugal motor power supply switch incorporated on the other end of the motor shaft !
When the centrifuge force exceeds the predetermined value ( that can be micro adjusted ) the power is cutoff the speed lowers the centrifuge force drops below the predetermined value and the switch engages again powering again the motor , that happens presumably many times per second , in practice the end result is a very accurate motor speed , who needs FG coils !

Sony TC-802 (photos above) uses an interpretation of this electromechanical motor speed stabilization in an oversized shape of the cylindrical motor that years later was used in the DD series but with an FG coil this time .
I was lucky to find this model many years ago in pristine condition , but the motor was completely dead.
Long story short , the motor brushes used the springy action of two tiny pieces of plastic foam to obtain firm contact with the commutator , these had been turned to dust after 40 or so years also the capacitor used to absorb current spikes from the aforementioned internal switch had gone bad at some point and the switch contacts lost any kind of conductivity , it was really hard to repair all this and equally hard to properly adjust the centrifugal switch .
After the repair it sounds great with natural sound really stable speed in any condition , and by now it has stood the test of time .
Now that potential collectors have been warned this is a very attractive machine with design unlike any other of its kind , high built quality well above from what pictures
can show.

The answer to why other manufacturers didn't use the Disc Drive system is simply because it was patented by Sony in 1987 (and designed by the brilliant engineer Mitsuru Ida) , at a time when portable cd players seemed to be the future , Sony rivals probably thought it was not a good investment to pay royalties for an aging medium and for some of them maybe it was also a matter of pride.

 

Great addition, thanks! It sounds a lot like a (centrifugal) governor that you can still see today in old machinery to keep the machine running at a predetermined, ideal speed. Usually by design to keep it from running to quickly and cause damage and to keep power/fuel consumption down.