I'm not really a tech-head (still very fond of CDM4Pro), but isn't the best transport perhaps a 3D scanner (only one moving part)? No idea how you would make the hardware or program the software for such an idea. 🙂
Again, just an idea that perhaps one could use for analogue and digital
Again, just an idea that perhaps one could use for analogue and digital
I would propose to regard the linear positioner
or linear drive as being set. Because Sony used the
same chipsets on them as well as on "classical"
mechs, evaluation should be relatively easy.
I throw the idea into the discussion that
for coarse movement the CD itself is being moved,
thus we are more free to implement the
fixed laser. I assume this system needs well
balanced parts to supress movement by off-
centered parts.
or linear drive as being set. Because Sony used the
same chipsets on them as well as on "classical"
mechs, evaluation should be relatively easy.
I throw the idea into the discussion that
for coarse movement the CD itself is being moved,
thus we are more free to implement the
fixed laser. I assume this system needs well
balanced parts to supress movement by off-
centered parts.
The (direct drive) linear slide used by Sony and others is like kicking a box to move it. Movement only happens when you kick with a high force to overcome the friction. The amount of movement is also not very precise and requires a fairly constant friction over the whole length of travel. A challenge to adapt it to work with the higher mass/friction of moving the CD plus other parts.
Are they using the same method of movment? Or a servo or stepper motor. I posted the link so that it would improve understanding. Claims about seektimes proves nothing about how it works.
Well, the mech discussed in the article is a BU-1 from Sony.
Got two players with it. I wonder if Mr Wotit who wrote it
was aware that those mechs are not produced any more.
The article sounds a bit like he assumed that linear motors
are common design in CD Players
Got two players with it. I wonder if Mr Wotit who wrote it
was aware that those mechs are not produced any more.
The article sounds a bit like he assumed that linear motors
are common design in CD Players
Hi Salar,
Yes, the linear tracking mechanism is fairly common in those pricier CD players. Yes, they used the same chip sets as the motor-gear products. Yes, they are noticeably quicker to position the head where it needs to be. This is a mechanism that I favor heavily. It's also fantastically reliable, needing only a clean and lubrication at intervals.
-Chris
Yes, the linear tracking mechanism is fairly common in those pricier CD players. Yes, they used the same chip sets as the motor-gear products. Yes, they are noticeably quicker to position the head where it needs to be. This is a mechanism that I favor heavily. It's also fantastically reliable, needing only a clean and lubrication at intervals.
-Chris
Hi Mark,
Servo motors are not used often (I have never seen one in a CD player). They are both noisy and slow compared to the linear slide types, making them an expensive, but more reliable option compared to the very common motor-gear combination most inexpensive CD players use.
Seek times and operating noise do matter when a customer is evaluating a CD player, and the linear motor is king of that hill. Having said that, it wouldn't surprise me to see a few pro-machines using stepper motor positioning. Pro machine referring to industry production equipment never seen by the public. You would actually be the authority on this I would think.
-Chris
Servo motors are not used often (I have never seen one in a CD player). They are both noisy and slow compared to the linear slide types, making them an expensive, but more reliable option compared to the very common motor-gear combination most inexpensive CD players use.
Seek times and operating noise do matter when a customer is evaluating a CD player, and the linear motor is king of that hill. Having said that, it wouldn't surprise me to see a few pro-machines using stepper motor positioning. Pro machine referring to industry production equipment never seen by the public. You would actually be the authority on this I would think.
-Chris
The linear slide is a servo where the feedback is sourced from the second coil and the tracking signal.
All the new ROM drives use stepper motors and a lead screw.
All the new ROM drives use stepper motors and a lead screw.
Keep it friendly guys.
NATDBERG, the theory of Redbook playback and data recovery is well established, in fact I spent 3 days with Sony in the early years, and servo design (covering focus/tracking/spindle) and how it all integrates and comes together as a whole was a major part of the course.
Over the years, a lot of myth and legend has appeared as to what may provide beneficial tweaks, or where the big designers got it wrong......
While its fine to put forward those ideas, you also need to back them up with real evidence that shows not only an improvement in performance, but also that it is not to the detriment of other areas of operation.
I put forward those ideas ages ago in this thread and those ideas were discussed. That ended a good while ago.
I have only recently spoken about the adding of any mass to a spindle and rejecting the assertion that adding mass causes problems which cannot be overcome - and I point to working examples of CD players still working 20 or 30 years which have much higher than average mass as evidence that they CAN be overcome and HAVE been overcome.
This is no argument here that the CD701 for example doesn't work so how can it be said that a higher mass cannot work and should not be contemplated and should be dismissed out of hand?
Sure, decide on priorities and decide against it as part of a design process .. but I simply don't think Anatech is keeping up with the thread and instead working himself up over some phantom stereotypical argument which is not being made by me at all.
So yes, he needs to calm down!
Sorry Chris, I think you are going a bit crazy about this.
What claims exactly do you think I am making? If you can clarify that then at least I can understand where your animosity is coming from.
The only claim I am definately making is that adding mass does not prevent CD players like the CD701 from working and therefore SHOULD there be anyone in this thread coming up with a scheme which may incidently add mass, then they absolutely should not be scared by you into silence.
For example, as much as you do not like them, many users do like to use a puck. It also simplifies the mechanics of a CD transport which helps the DIYer. And so a mech which can cope with the added mass of a puck and the mass of whatever an end-user wants to throw at it, should be provided for in the design of the basic mech mechanics (torque of motor for example).
If you wish to dictate what the end-user can and cannot do with the mech by narrowing the spec to a specific application simply because you only want to see people building CD transports the way you wish to build them.. then I politely suggest you would be damaging the mech's appeal. Go ahead and give it a weak-*** motor just to spitefully scupper their plans!
By way of moving the thinking beyond the CD-Pro2 style construction. Here's an interesting mech design by Denon:
Note how the motor section is a fairly simple mounting using bolt together parts (rather than a cast plate) and the laser, a swing-arm in this case, is attached to this motor base. It's a rather naked design that people are not used to these days but does lend to a modular design which may be easier to manufacture, construct, repair and modify.
Note how the motor section is a fairly simple mounting using bolt together parts (rather than a cast plate) and the laser, a swing-arm in this case, is attached to this motor base. It's a rather naked design that people are not used to these days but does lend to a modular design which may be easier to manufacture, construct, repair and modify.
Chris,
A bit O/T but something which I believe was lightly touched upon earlier in the thread. The Philips CDM-1 mechs were used widely but I've seen reference to those fitted to the Marantz CD94 and CD-12 (Philips CD-960 / LHH-1000) in particular as being 'tuned versions'. I was wondering if this was something confirmed to you by the factory and if you know just what this entailed? Or might it have just been marketing?
Thanks.
A bit O/T but something which I believe was lightly touched upon earlier in the thread. The Philips CDM-1 mechs were used widely but I've seen reference to those fitted to the Marantz CD94 and CD-12 (Philips CD-960 / LHH-1000) in particular as being 'tuned versions'. I was wondering if this was something confirmed to you by the factory and if you know just what this entailed? Or might it have just been marketing?
Thanks.
Hi Jonssen,
Wow, that was a long time ago in the life of CD transports. I'll be honest with you in that I had never heard of a tuned CDM-1 in anything. You have to figure that Revox and Studer used the very best in the way of transports, and they attempted to provide "right down to the component" type service for everything. If Studer or Revox didn't use anything like a tuned transport, I have trouble believing they were actually available. Back then, everyone pulled out all the stops to produce the best mech they could.
Philips transports were characterized by the base casting and basic parts being the normal way they would sell it. Then they added options (the slash code at the end of the number). I have seen these option lists and they did not include a tuned variant. To be honest with you - I can't see how a tuned version would exist as they were all adjusted as close to perfect as could be expected. Anything not "tuned" was "broke" and needed replacement.
I am wondering if that term wasn't maybe in the sales literature and maybe called out the brushless motor and some other accessories. There wasn't anything a manufacturer could do to "tune" anything except adjust it exactly per the manual (which we did anyhow). In the early days we had problems with not reading CDs, or skipping. Stuff that happened due to defective manufacture or poor handling. My favorite: CDs left in the bright sun that developed poor tracking and sound issues. Therefore, every company was very sensitive as to how their machines were serviced and set up. We really were under the gun to service units exactly per the manual and as close as we could get them to the performance level expected.
I'm sorry Jonssen, I can't confirm that one for you. I do have real doubts over what would have constituted a "tuned version". If you have any more information on this, it might be very interesting.
-Chris
Wow, that was a long time ago in the life of CD transports. I'll be honest with you in that I had never heard of a tuned CDM-1 in anything. You have to figure that Revox and Studer used the very best in the way of transports, and they attempted to provide "right down to the component" type service for everything. If Studer or Revox didn't use anything like a tuned transport, I have trouble believing they were actually available. Back then, everyone pulled out all the stops to produce the best mech they could.
Philips transports were characterized by the base casting and basic parts being the normal way they would sell it. Then they added options (the slash code at the end of the number). I have seen these option lists and they did not include a tuned variant. To be honest with you - I can't see how a tuned version would exist as they were all adjusted as close to perfect as could be expected. Anything not "tuned" was "broke" and needed replacement.
I am wondering if that term wasn't maybe in the sales literature and maybe called out the brushless motor and some other accessories. There wasn't anything a manufacturer could do to "tune" anything except adjust it exactly per the manual (which we did anyhow). In the early days we had problems with not reading CDs, or skipping. Stuff that happened due to defective manufacture or poor handling. My favorite: CDs left in the bright sun that developed poor tracking and sound issues. Therefore, every company was very sensitive as to how their machines were serviced and set up. We really were under the gun to service units exactly per the manual and as close as we could get them to the performance level expected.
I'm sorry Jonssen, I can't confirm that one for you. I do have real doubts over what would have constituted a "tuned version". If you have any more information on this, it might be very interesting.
-Chris
NATDBERG,
I think you should be quiet now. You have accused me of things I am not guilty of, and you seem to be trying to create trouble. I'm not trying to scare anyone into silence, but do have a problem with your approach to your beliefs and how you go about forcing the topic you wish to discuss onto others.
Sadly, the mechanisms that you like from Teac / Tascam are ones I am an expert on. You are reluctant to accept any first hand observations I have made about them. That means that you cannot be reasoned with and fail to understand the simple physics behind what makes a CD go.
This is the last time I will address your posts.
-Chris
I think you should be quiet now. You have accused me of things I am not guilty of, and you seem to be trying to create trouble. I'm not trying to scare anyone into silence, but do have a problem with your approach to your beliefs and how you go about forcing the topic you wish to discuss onto others.
Sadly, the mechanisms that you like from Teac / Tascam are ones I am an expert on. You are reluctant to accept any first hand observations I have made about them. That means that you cannot be reasoned with and fail to understand the simple physics behind what makes a CD go.
This is the last time I will address your posts.
-Chris
NATDBERG, The problem is that you see higher mass or clamping force as the goal here when in reality the designs you put forward don't accomplish this. The CD701 is a good example. What does it do better than other players? The answer can not be "it has more mass so it must be better". You need to explain why higher mass is an improvement. I like the idea of placing the spindle motor above the disc as used in the CD701. Is it really better than placing it under the disc? The same for the swingarm designs. Why would they work better? Are they easier to build? Can they work with three beam tracking? Are they more reliable? And, the answers should be technical, not BS. The same goes for anyone with a different opinion.
The idea of the option of using a puck. Does it complicate the design? will it improve playback? Salar's last idea is a good example. We just about understand how the linear slide works and he wants to see if we can implement it in a fixed optic design. No explanation as to why. My reply should have been "are you kidding?".
The idea of the option of using a puck. Does it complicate the design? will it improve playback? Salar's last idea is a good example. We just about understand how the linear slide works and he wants to see if we can implement it in a fixed optic design. No explanation as to why. My reply should have been "are you kidding?".
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The Denon DCD-1800 mech was already discussed. It was
unreliable (rubber surface) and shows angular
errors.
unreliable (rubber surface) and shows angular
errors.
Hi Chris,
This 'tuned version' business (CDM-1) is mentioned in a few places:
http://www.dutchaudioclassics.nl/philips_cdm_cd_mechanisme_list/
"Later, a special fine-tuned version of the Philips CDM1 developed for use in high-end players like the Marantz CD-94 and Marantz CD-95."
Marantz & Philips CDM drives on TVK, part #1
See table
DIY Audio Projects Forum • Marantz CD-95
See post (BTW, what's the 'TDA motor driver'?)
It doesn't make much sense to me either. Perhaps it's all disseminated from the mention on the Dutch Audio Classics site. Could it be 'special selection' in the same way the TDA1541 DAC chips were said to earn their crown ratings?
Philips TDA1541A d/a converter - DutchAudioClassics.nl
Jon.
P.S. The Dutch Audio Classics site credits the information to: All About Marantz - Stereo Sound.
"For the 50th Anniversary of Marantz in 2003 Stereo Sound published a limited-edition “All About Marantz” history book"
http://www.dutchaudioclassics.nl/Fo...-About-Marantz-Stereo-sound-50th-Anniversary/
http://www.amazon.com/Stereo-Sound-Marantz-Japanese-magazine/dp/488073098X
I'm becoming more sceptical... :-\
This 'tuned version' business (CDM-1) is mentioned in a few places:
http://www.dutchaudioclassics.nl/philips_cdm_cd_mechanisme_list/
"Later, a special fine-tuned version of the Philips CDM1 developed for use in high-end players like the Marantz CD-94 and Marantz CD-95."
Marantz & Philips CDM drives on TVK, part #1
See table
DIY Audio Projects Forum • Marantz CD-95
See post (BTW, what's the 'TDA motor driver'?)
It doesn't make much sense to me either. Perhaps it's all disseminated from the mention on the Dutch Audio Classics site. Could it be 'special selection' in the same way the TDA1541 DAC chips were said to earn their crown ratings?
Philips TDA1541A d/a converter - DutchAudioClassics.nl
Jon.
P.S. The Dutch Audio Classics site credits the information to: All About Marantz - Stereo Sound.
"For the 50th Anniversary of Marantz in 2003 Stereo Sound published a limited-edition “All About Marantz” history book"
http://www.dutchaudioclassics.nl/Fo...-About-Marantz-Stereo-sound-50th-Anniversary/
http://www.amazon.com/Stereo-Sound-Marantz-Japanese-magazine/dp/488073098X
I'm becoming more sceptical... :-\
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