CDM 4/11 vs CDM 4/19 - diyAudio
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Old 17th August 2006, 02:14 PM   #1
adhoc is offline adhoc  Australia
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Question CDM 4/11 vs CDM 4/19

Hello all,

First off, like a good boy, I have searched. But I have still not gotten all the information I need.

I here today asking about the differences between the 4/11 and 4/19 CDM mechanisms.

From my research here, all I can tell is that the 19 is the 'standard' version while the 11 is the 'hall motor' version. Can anyone tell me what 'hall motor' means? Is this a better motor?

If someone could point out any other differences, I would be most grateful.

Cheers!
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Old 17th August 2006, 02:28 PM   #2
anatech is offline anatech  Canada
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Hi adhoc,
The /XX is the option code, as you have mentioned. A hall motor is one where the disc motor has no brushes. The coils are energized in sequence from the rotor position. Hall effect elements provide the position information.

These motors are the ones you see where the rotor sits just over a small circuit board. It's a very flat assembly, but wide.

-Chris
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Old 17th August 2006, 02:48 PM   #3
adhoc is offline adhoc  Australia
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anatech, thank you for your reply.

My research here has indicated that 'brushless' motors make for superior transports due to their better mechanical characteristics. Am I correct? Would you happen to be able to elaborate on these 'better mechanical characteristics'?

Cheers!
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Old 17th August 2006, 02:55 PM   #4
anatech is offline anatech  Canada
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Hi adhoc,
That is a question that has many variables. It depends on the number of poles for one. It's true there are no brushes to wear, but I see more bearings gone anyway.

I have a deep distrust for anything Philips makes. They are usually very inexpensively constructed. So I will not comment any further.

-Chris
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Old 21st August 2006, 10:03 AM   #5
PetrL is offline PetrL  Czech Republic
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Adhoc, a Philips player with CDM4 *can* make excellent transport. I use one with CDM4/25 (? -- no sticker). But I also have CD650 with CDM2/10 which is clearly much worse. Both have hall motor... Now I bought same player as first one, but with CDM2 mechanism, so I'll compare them. The thing is that the radial bearing of the rotor on these motors isn't very good or durable, one has to select, which is not too expensive.

"I have a deep distrust for anything Philips makes" -- same for me, except for those swingarm transports and tda1541 But this is history.
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Old 24th August 2006, 08:01 AM   #6
PetrL is offline PetrL  Czech Republic
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Only to close my previous post: the other player with CDM2/29 is equaly good transport as the one with CDM4/25(?). Very good microdynamics top to bottom. Pitty that CD-650 doesn't catch it at all, because it has remote. Perhaps a jitter problem...
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Old 26th August 2006, 08:59 AM   #7
tubee is offline tubee  Netherlands
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The on the CDM-2 is not that bad. I have played 18 years (!) with a CDM2 in CD640, it still plays. Every Philips (standard) CDM after its predecessor became more flimsy every time. CDM-0 & 1 has roll bearings on arm, Cdm 1 is from alu. CDM 2 has all features of 0 and 1 but single ball as bearing and more plastic as base, though this is quite rigid glass fibre filled polyester. Imo the CDM 4 is the last reasonally good CDM, but there are exceptions: CDM-4/25 is not as good as other CDM-4's with lower suffix #.
My current project has a modified CDM2-(00081 as suffix#) This diy player weighs about 8 kg's allready.
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Old 26th August 2006, 09:37 AM   #8
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Quote:
Originally posted by adhoc
anatech, thank you for your reply.

My research here has indicated that 'brushless' motors make for superior transports due to their better mechanical characteristics. Am I correct? Would you happen to be able to elaborate on these 'better mechanical characteristics'?

Cheers!
Brushless motors do radiate far less RF. In (for example) a TEAC T1 I can measure that at the SPDIF output. 2 capacitors solve a lot of these problems.

best
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Old 26th August 2006, 01:55 PM   #9
anatech is offline anatech  Canada
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Hi Guido,
Quote:
Brushless motors do radiate far less RF.
I hadn't considered that, of course it is undeniably true!

-Chris
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Old 28th August 2006, 08:25 AM   #10
PetrL is offline PetrL  Czech Republic
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I think the CDM4/25 is older than CDM4/19, even older than CDM4/11. It has just different laser head than CDM2 or CDM4/11, the rest seems equal. Re the bearing, is there a reversible way to take away the platter from shaft? This would allow a bronze bushing or the like and new life for these plastic chassis, better than new.
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