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Old 5th September 2015, 03:30 PM   #1
Salar is offline Salar  Germany
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Default Quality CD-Mechanisms are long gone - let us build one ourselves!

I went to IFA fair in Berlin, spending a day in the area reserved for suppliers. Only one displayed boomboxes. None displayed OEM CD/DVD mechanisms.
One offered contact to some nonamers in China.
The CEO of an european company which does OEM for many High End CD told me, that Sanyo is the only brand left, that produces mechs for audio.
Sony, Philips (now Gibson) left the market. But Sanyo was aquired by Panasonic in 2011.
No hint on Panasonic Industrial that CD/DVD mechanismss are still produced for OEM.

So we are in the same situation as the record industry in the late eighties - which ended in producing sought high quality gear!

Patents for the CD have expired - so why not producing our own
high quality mechs? If a prototy can be built, crowdfunding could be the next step for mass production.

Some parts like laser diodes can be still obtained, there are some experts
in this forum who know a lot about laser assemblies, many broken assemblies can be scrutinized and compared and maybe even some retired developers can be found to give advice.
There is 3D printing for prototyping, the tough part will be the optical system, coils and proper aligning.
My dream would be a "classical" three beam laser which could be placed on different "baseplates" and therefor mechanically (and electronically) aligned to fit into older traverse mechanisms
as well as using it for actual DIY projects.

So the High End classic from the eighties can be revived (But I assume many of them are still running) or a diy player can be built from scratch.
Another "dream" would be swappable laser diodes thus they are the only aging part. (as far as I know, individual alignment is needed)
Brushless motors for durability are another must.

For the option of replacing old lasers:
Sony was a major supplier of RF amplifiers and servo controllers,
about three generations of ICs for RF amplification / servo Control / decoding were used roughly within the first ten years of production.
Later decoding and servo control was combined on one IC.

As for today, I have no idea, which decoders and servos are obtainable and can will be produced in the future.

Thread opened, any propositions?
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Old 5th September 2015, 03:35 PM   #2
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Maybe because it is the absolute end of the optical media era ? Haven't touched a CD for at least 3 years....and then, who still buys them ? It won't be a surprise that we will read that the media themselves are not produced anymore one of these days. I don't think nostalgia as with record players will let CD survive as it can already be seen that music is distributed on USB keys. The trend seems to be very high resolution files which CD players don't play. Playing FLAC or WAV on a nice SSD equipped media player is more convenient and better sounding in many cases. True, manufacturers are not very keen on audio anymore so many new audio devices have something to desire for. Some are nicely engineered devices that offer more possibilities than CD players and take a lot less space in the house. No need to adjust mechanics and to find obsolete laser units anymore

The special RF amplification/servo control/decoding chips are not produced by the big names anymore as they left the market or they are about to leave the market. if you insist on going on with CD then you will have to look into the chinese manufacturers that still produce CD stuff. I am not sure if quality is of prime importance for them. So even if you can make a mech and a laser (which will cost many hours), then the hunt for chips will begin. It probably is way easier to find a good old CDM4 player and find an extra mech for it in case it breaks down.

It will probably cost way less time and money to convert all your CD's to (lossless) FLAC files and play those on a low jitter audio player likely with better sound quality.

You never know what can happen though :

http://www.bloomberg.com/news/videos...ssette-factory
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Last edited by jean-paul; 5th September 2015 at 03:56 PM.
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Old 5th September 2015, 03:37 PM   #3
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The "RF" part and decoding is best done in ADC + DSP these days. An ASIC costs too much
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Old 5th September 2015, 05:07 PM   #4
anatech is online now anatech  Canada
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Hi Salar,
I agree completely. I do think it is worthwhile to create a flexible mechanism that will accept various laser assemblies. One thing I can guarantee is that with better transverse assemblies, you can make a vast improvement in the sound quality. So the better CD player depends on the head and transverse assy's. Chip sets for computer DVD / CD ROMs are available. But if you look back at the beginning, it was all done with op amps and SSI and MSI digital chips (small and medium complexity chips). Certainly a PIC can be programmed to process the transverse assy commands, plus run the digital side (or use two chips). Microchip has DSP chips and they can be reprogrammed while installed on the PCB. So we have I-V conversion and amplification to give us an RF waveform. The decoding engine can be a currently manufactured chip, or a DSP running a program - along with maybe a little more data memory for error correction. The D/A converter and audio path can be modular so you can have whatever decoding engine you want, coupled with tube, discrete or IC technologies. When I say tube stage, I mean more than a single token tube.

Then there is the chassis. Proper decoupling can be given attention, and it can become a beautiful work of art. So a new model is merely an alternate case and maybe some code touch-ups. Integration to home automation, or common control from the system can be retrofitted once the more popular formats are figured out.

A basic device that is extremely good with a set of options as the owner decides on, or wants to add later. We have experts in each field to call on for support. Using something like Microchip micro-controllers will free us from availability worries.

I don't know about replaceable laser diodes, but I would like to see that. Sanyo made some really good heads, they fell down by not making a good transverse mechanism. The heads didn't have a bearing surface and those wore out quickly. That, we have sorted out.

-Chris
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Old 5th September 2015, 06:10 PM   #5
Salar is offline Salar  Germany
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@jean-paul
I would rather prefer to stay on topic and not start a general if a development is useful.

But your link to the cassette factory is encouraging.
At least the funeral for the CD is luxurious, this is actually sold for $17.500!
C.E.C. TL 0 CD transport | Stereophile.com
Pressed CDs will probably last until 2080. Would be nice to have a mechanism that still works then.

-Goal is to develop a durable CD-Mechanism which is at least on par with
first generation mechanisms. This is not nostalgia. This mechs were top notch
with glass lenses and completely serviceable and adjustable laser heads.
Also brushless motors were widely used, gears was solid without play.

-Goal is to gather people here who might be willing to contribute their skills.
Some people / developers from the beginnings are welcome
-Goal is to find the suppliers needed for this mechanism.
-Goal is to develop a prototype with mechanics and servo systems which leads to
crowdfunding for mass - production.

I can provide the mechanical stuff like designing and milling the laser head and mechanism. In electronics I am an idiot. There is better people in the forum to deal with electronics.

@anatech.
No,I meant that it would be nice, if this newly developed laser head only could fit into old players (using mechanical / electronical adaptation)
But designing a new mechanism is the main goal. I completely agree to your post.

This is how the task was done in first generation consumer players:

SONY CDP-101 DE Service Manual free download, schematics, eeprom, repair info for electronics
PHILIPS CD100-00-05 SM Service Manual free download, schematics, eeprom, repair info for electronics
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Old 5th September 2015, 06:55 PM   #6
anatech is online now anatech  Canada
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Hi Salar,
I am really interested to see where we can take this.

The combination of a good transport and good electronics will be the first time they were put together. Old machines that worked had large, beautiful eye patterns. Today's chip sets can pull material from almost closed eye patterns. Imagine what they can do with a clear, open eye pattern. Stick this together with modern logic control and the D/A converters available today and you have something pretty special. Even the op amps are better these days!

I'll help where I can Salar.

-Chris
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Old 5th September 2015, 07:56 PM   #7
Salar is offline Salar  Germany
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Hi Chris!
That sounds great, lets start!

First shot, laser diodes.

http://rohmfs.rohm.com/en/products/d...eam/all_ld.pdf

Any other manufacturers? And where to look for photodiodes?
All the best, Salar
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Old 5th September 2015, 08:15 PM   #8
anatech is online now anatech  Canada
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Hi Salar,
You will notice that there is an extra diode in each. It is used as a monitor for laser output control.

Why not try to identify a laser head first, then figure out what laser diode it uses and go that way. Even the horrible HOP-M3 might work well in a different transverse mechanism. Note that that head is as cheap as you can probably get. The entire body is cheap plastic, so it will probably change dimensions in the longer run.

The Sanyo SF-90 line of heads is in a cast metal body, plus it usually has a nice eye pattern. This would be my suggested course to take. The signal is strong enough as to not need the I-V converters on the head. You could mount that stuff in the sled if you felt that strongly about it. Anyway, I think the optical path in the SF-90 is the best of everything that might be available. Once you have stable optics, you can worry about changing the laser diodes.

-Chris
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Old 5th September 2015, 08:33 PM   #9
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OK, I adapt. Is the choice for a laser diode also depending on what kind of mechanism will be used ? So the swingarm type, the later cheap "carriage" type mechs or the "floating" mechanism. I liked the Philips CDM swingarms a lot (no problem with gap of 4 mm) but the Pioneer magnetic floating mechs were faster and had no friction as the laser unit was floating in the air in a magnetic field ("Magnetschlitten "). Particularly the mech as used in Pioneer PD-8500 was a very fast and good one. No need to lubricate etc.

Pioneer PD-8500

Maybe the project will run more fluid if design goals are stated ? Choice of laser diode, choice of type of mechanism, direct drive or belt driven, choice of spindle motor (brushless 4 phase I take ?) and of course check availability of those parts first. If you like the CDM type swingarms you could take a cast aluminium chassis of an old CDM1 and design according the same dimensions and find a suitable laser and spindle motor for that. It will make it possible to fit the mechanism in older Philips/Marantz etc. CD players. The cast aluminum chassis is shaped not very complicated.
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Last edited by jean-paul; 5th September 2015 at 08:47 PM.
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Old 5th September 2015, 08:55 PM   #10
anatech is online now anatech  Canada
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Hi jean-paul,
Quote:
I liked the Philips CDM swingarms a lot
Have you seen the procedure to align the laser on those??? It is a nightmare that was properly a factory only setup. We had problems with the flexible PCB from the head.
Quote:
direct drive or belt driven
What was belt driven, the feed motor?
Quote:
Particularly the mech as used in Pioneer PD-8500 was a very fast and good one
The lens used to fall out of those, cheap crappy heads. I have one spare for a Denon machine.
The Sony KSS-151A mechanism was much better, faster due to lower mass. The Sony heads seemed to last just fine. Check the Tascam CD-401. The upper Denon machines used that head as well.

-Chris
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