Test CD for CD player adjustment

[anatech]

Hi DMJ3000,
I don't use YEDS series discs, but often it isn't the audio track that is important. It is the defect or lack of defects that are the point of the track. A constant tone make it easier to hear errors in tracking.

For focus offset, any CD that is within spec. can be used to set focus offset. Philips 5 test disc is stated as a standard Redbook CD. I'm sure almost every test disc series has one. Denon used certain commercial pressings (music CD's) that they tested for this. They even had a correction for tracking and focus gains depending on the CD (CA-1094 was the old number). So as long as you know the CD is within spec., you can use it. Let's face it, a good pressing will be closer than nothing, but a bad one can sent you off on your setup.

-Chris

[DMJ3000]

Hi anatech,
thanks for your useful information.

[Lourens]

Can somebody tell me what’s on the Philips/Studer Test CD 3, track 1? Need it for adjusting the laser current of the cdm1 in my Studer A727, according to the service manual.
BTW it should be really interesting to see the whole table of content of that cd...

[anatech]

Hi Lourens,
It may be the same as Philips #5. You could set the current with another service manual from Philips that uses the same CDM. I believe they output around 0.08 mW if you have a laser power meter. That would be in the ballpark.

The reflectivity of the disc is the important thing there. In other words, you really do need to use that CD in particular. No, a copy of it is quite useless.

-Chris

[Lourens]

Hi Chris,
Thanks for your quick response. You could be right. Unfortunately the service manuals of Philips CDM1, and the players using this drive, follow a very different adjustment method from the one in the A727 manual (see attachment), using Test cd 4822 387 30096 track 1 (is this #5?) or a laser simulatorprint....
Do you know what kind of signal (KHz, dB) is on track 1?

Lourens

[anatech]

Hi Lourens,
Interesting. The procedure you have listed looks very similar to the training I received with Philips. I'm trying to remember back. I am pretty sure this is Philips Test CD #5. The tracks are simply music (that I am sick off). It is the reflectivity of the CD that is important. So you see, it has nothing to do with the material encoded on the disc.

My copy of Philips #5 gives a low level, so that you tend to turn up the laser power too high. I found that out when a Philips tech was giving me hell. I brought my disc (bought from them) up and proved it was not my fault. It was actually set bang on with my disc. BTW, my cost was $200 for #5 and $250 for 5A. No choice, I had to buy them. Stinkers. No other test discs cost so much. Rape and pillage.

Your part number is a Revox number. I am pretty sure it is Philips #5.

-Chris

[Lourens]

Hi Chris,
Sorry I invoked such anger. I guess it was (and is!) just a matter of commercial self esteem to exercise ones monopolistic rights?
Meanwhile it is still a bit confusing looking at the different approaches for laser adjustment. I compared several manuals, all of cdm1 equipped players from Studer (A727), Revox (B126/226) and Philips (CD104/204/304). The attached clips do show a certain consistency in the used test cd's though. My conclusion is that they all refer to the same disc numbers, but with different titles and part numbers:
#3 Revox part number 46240 = Studer 10.241.023.00 = Philips "Disc without defects" 4822 397 30096
#5/5A Revox 46241 =Studer 10.241.026.00

Never mind. I was just curious how to find an easy way to check some laser parameters after I compared a recently serviced A727 (ex NOB, Dutch public broadcast) with my own ones. In one of those I replaced the cdm1 for an almost unused one from a Philps CD104. They all sound different, of course

Lourens

Revox parts list:

[Lourens]

The Studer equivalent:

[Lourens]

Laser adjustment from Philips CD304/II manual:

[Lourens]

Revox laser adjustment: