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
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
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
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
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
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
Attachments
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
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
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:
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:
Attachments
Hi Lourens,
No, you didn't make me angry in the least. Sorry if it read that way.
I was in my 20's when I was forced to buy those CDs. A big chunk of cash for a young guy. I've always found Philips to charge far too much for their spares. I have trouble finding any respect for that company. High prices and very poor customer support.
It appears that the different instructions pertain to a different RF level due to circuit changes. I am positive the actual CD is the same (5 & 5A). I used to do warranty on Revox product and was starting Studer when Harmon International bought Studer. They used the exact same dics that I already had.
Notice the mirror disc? I think they wanted around $500 for it back then. We tried to use it to set up the arm, it took too much time and they determined that this would be a factory job only. I'm so glad I didn't buy that disc.
-Chris
No, you didn't make me angry in the least. Sorry if it read that way.
I was in my 20's when I was forced to buy those CDs. A big chunk of cash for a young guy. I've always found Philips to charge far too much for their spares. I have trouble finding any respect for that company. High prices and very poor customer support.
It appears that the different instructions pertain to a different RF level due to circuit changes. I am positive the actual CD is the same (5 & 5A). I used to do warranty on Revox product and was starting Studer when Harmon International bought Studer. They used the exact same dics that I already had.
Notice the mirror disc? I think they wanted around $500 for it back then. We tried to use it to set up the arm, it took too much time and they determined that this would be a factory job only. I'm so glad I didn't buy that disc.
-Chris
I want to check the focus gain and tracking gain adjustments on my VRDS-T1 transport and note that the manual calls for use of track 4 from YEDS-18. Having read the previous post I'm wondering if I can use an alternative test disc like CD-CHECK or a self generated test tone to perform these operations or am I tied to using the YEDS-18 disc?
Also does anyone know of a source for the PV test discs? Seems to be OOP at present.
cheers
Paul
Also does anyone know of a source for the PV test discs? Seems to be OOP at present.
cheers
Paul
Hi spzzkt,
Track 4 on YEDS-18 is a testtone of 100Hz, full scale (0dB Headroom).
There are no simulated errors on YEDS-18 like on CD-Check
You can use CD-Check, my disc provided a very clear eyepattern.
Track one on CD-Check is error free. The only problem is, after 20 seconds the testtone (500hz mixed with 20khz) will fade to silence. So the eypattern will have lesser lines to judge.
BTW Focus/tracking gain adjustments on my Nakamichi was to be done without playing a disc. One IC had to be fed with a generated testtone (!) using a bandpassfilter. Strange and too complicated for me.
I then made the fine tuning with two ordinary discs. One very old Polygram with some very sharp dropouts, but normal reflection. (Manufacturing errors, I guess)
The other one was a burned CD, which is lesser reflective.
When the Polygran disc played with no dropouts, the burned CD would not play at all. The sweet spot was where both discs would play.
But every company seems to have different adjustment procedures, even though the players might share the same laserhead. I don´t recall the adjustment procedures of the Sony 552ESD, (released the same time as my Nak, 1986) but as far as I remember, for adjusting focus/tracking gain on this player, a CD with simulated dropouts was needed.
All the best,
Salar
Track 4 on YEDS-18 is a testtone of 100Hz, full scale (0dB Headroom).
There are no simulated errors on YEDS-18 like on CD-Check
You can use CD-Check, my disc provided a very clear eyepattern.
Track one on CD-Check is error free. The only problem is, after 20 seconds the testtone (500hz mixed with 20khz) will fade to silence. So the eypattern will have lesser lines to judge.
BTW Focus/tracking gain adjustments on my Nakamichi was to be done without playing a disc. One IC had to be fed with a generated testtone (!) using a bandpassfilter. Strange and too complicated for me.
I then made the fine tuning with two ordinary discs. One very old Polygram with some very sharp dropouts, but normal reflection. (Manufacturing errors, I guess)
The other one was a burned CD, which is lesser reflective.
When the Polygran disc played with no dropouts, the burned CD would not play at all. The sweet spot was where both discs would play.
But every company seems to have different adjustment procedures, even though the players might share the same laserhead. I don´t recall the adjustment procedures of the Sony 552ESD, (released the same time as my Nak, 1986) but as far as I remember, for adjusting focus/tracking gain on this player, a CD with simulated dropouts was needed.
All the best,
Salar
Hi Paul,
Now, one more time. You can not copy or create a test disc for the purpose of setting up a CD player. It's not the encoded information you need! What is required are the physical constants of the disc in question. Reflectivity, pit shape, pitch and more are the things you need. These are all dependent on the recording and materials used in the manufacture of a disc. By virtue that recordable CD's are made differently than the ones stamped out (like an LP record - or 45 rpm I guess), they will be worse to use than any old CD premade with music on it.
Same goes for test tapes BTW. And still people try to make their own!
-Chris
That would be a wise move.
Now, one more time. You can not copy or create a test disc for the purpose of setting up a CD player. It's not the encoded information you need! What is required are the physical constants of the disc in question. Reflectivity, pit shape, pitch and more are the things you need. These are all dependent on the recording and materials used in the manufacture of a disc. By virtue that recordable CD's are made differently than the ones stamped out (like an LP record - or 45 rpm I guess), they will be worse to use than any old CD premade with music on it.
Same goes for test tapes BTW. And still people try to make their own!
-Chris
Hi Paul,
Sine wave signal. You use it to set the gain of the focus or tracking servo. Normally this is done while the unit is playing a CD with no defects. This bit is very important.
This method was very common in earlier or higher end CD players. It is not a fine adjustment and you will find a bit of latitude in the adjustment. I wouldn't touch this one. The critical electrical adjustments would be the tracking and focus offsets. E-F balance is the most critical adjustment. Then you may find slice level, VCO and a DC for the VCO (early Philips) and sometimes a 7.35 KHz adjustment on early Sony types. There are others that engineering departments have cooked up. These days its mostly active servo to give "okay" performance. Other times the pots have been replaced with fixed resistors. Really, how much would it cost to leave the trimmer in??
There are a number of mechanical adjustments in some players. Firstly, make sure the disc table height is bang on. If there is a diffraction grating adjustment, it's unpleasant. It is a hairy, fine adjustment and you may scratch discs doing this. Do not do unless you have to. Early Pioneer heads are famous for this and they will not run out of the box. Azimuth is another (early Yamaha) and possibly a few more. Some times you may have to shim the guide rods even though there is no adjustment proper. This separates the men from the bald men. Some adjustments interact. Yahoo!
The OMS-5/7 have every adjustment pretty much (except diffraction - thank goodness!). They are almost perfect when done correctly.
-Chris
Edit: I haven't seen those discs in a while. Let me know if you find them please. Old Colony Sound used to sell them.
Sine wave signal. You use it to set the gain of the focus or tracking servo. Normally this is done while the unit is playing a CD with no defects. This bit is very important.
This method was very common in earlier or higher end CD players. It is not a fine adjustment and you will find a bit of latitude in the adjustment. I wouldn't touch this one. The critical electrical adjustments would be the tracking and focus offsets. E-F balance is the most critical adjustment. Then you may find slice level, VCO and a DC for the VCO (early Philips) and sometimes a 7.35 KHz adjustment on early Sony types. There are others that engineering departments have cooked up. These days its mostly active servo to give "okay" performance. Other times the pots have been replaced with fixed resistors. Really, how much would it cost to leave the trimmer in??
There are a number of mechanical adjustments in some players. Firstly, make sure the disc table height is bang on. If there is a diffraction grating adjustment, it's unpleasant. It is a hairy, fine adjustment and you may scratch discs doing this. Do not do unless you have to. Early Pioneer heads are famous for this and they will not run out of the box. Azimuth is another (early Yamaha) and possibly a few more. Some times you may have to shim the guide rods even though there is no adjustment proper. This separates the men from the bald men. Some adjustments interact. Yahoo!
The OMS-5/7 have every adjustment pretty much (except diffraction - thank goodness!). They are almost perfect when done correctly.
-Chris
Edit: I haven't seen those discs in a while. Let me know if you find them please. Old Colony Sound used to sell them.
I made a strange experience concerning simulated errors on CD-CHECK. (Black stripes on the disc surface)
My Nak did fail already with 0.3 mm defects. My other player, a CDP-X5000 would play CD-CHECK with defects up to 1.2 mm.
I mentioned a Polygram disc I used for adjustment, which has errors on the reflective aluminium layer, not on the disc surface.
Even though these errors are very small, the Sony did fail to play this disc.
I managed to align the Nak to play the Polygram disc without clicking, but it did not improve in playing CD-CHECK at all.
Same with a cheap Phillips 723, passed all error levels of CD-Check, but failed to play errors on the reflective layer of the Polygram disc.
Do focal lenght of lenses differ in order to blur out scratches?
CD-CHECK has a 500hz sine wave mixed together with a 20000khz sine wave. The purpose is to give interpolation a tough job so that small errors are audible. But this mixed signal also helps to track down weak D/A Converters.
The Sony and Nak played played this mix perfectly (i.e only 500hz were audible - my hearing stops at 16khz),
But the Phillips (1-bit converter like the Sony) played the signal with weird "overtones" - sounded like 500hz were sent through a vocoder...
My Nak did fail already with 0.3 mm defects. My other player, a CDP-X5000 would play CD-CHECK with defects up to 1.2 mm.
I mentioned a Polygram disc I used for adjustment, which has errors on the reflective aluminium layer, not on the disc surface.
Even though these errors are very small, the Sony did fail to play this disc.
I managed to align the Nak to play the Polygram disc without clicking, but it did not improve in playing CD-CHECK at all.
Same with a cheap Phillips 723, passed all error levels of CD-Check, but failed to play errors on the reflective layer of the Polygram disc.
Do focal lenght of lenses differ in order to blur out scratches?
CD-CHECK has a 500hz sine wave mixed together with a 20000khz sine wave. The purpose is to give interpolation a tough job so that small errors are audible. But this mixed signal also helps to track down weak D/A Converters.
The Sony and Nak played played this mix perfectly (i.e only 500hz were audible - my hearing stops at 16khz),
But the Phillips (1-bit converter like the Sony) played the signal with weird "overtones" - sounded like 500hz were sent through a vocoder...
Hi Salar,
I hate "bitstream" or single bit types of D/A converters. Give me a multibit any day.
Different servo systems will deal with defects in different ways. You can't really equate them easily. In other words, get the machine playing the best you can on real discs.
The Nak OMS-5/7 is a single beam player, not like later models that were three bean players. Pit shape is very important for single beam systems.
The test tones generally only test audio systems as you've noted. I have never seen a 20 KHz mixed with 500 Hz signal. I bet it's revealing. The 500 Hz tone is normal to see on tracking disc as it is normally very easy to hear drop outs in a single tone. Too bad a counter connected to the C1 / C2 flags isn't more common.
-Chris
I hate "bitstream" or single bit types of D/A converters. Give me a multibit any day.
Different servo systems will deal with defects in different ways. You can't really equate them easily. In other words, get the machine playing the best you can on real discs.
The Nak OMS-5/7 is a single beam player, not like later models that were three bean players. Pit shape is very important for single beam systems.
The test tones generally only test audio systems as you've noted. I have never seen a 20 KHz mixed with 500 Hz signal. I bet it's revealing. The 500 Hz tone is normal to see on tracking disc as it is normally very easy to hear drop outs in a single tone. Too bad a counter connected to the C1 / C2 flags isn't more common.
-Chris
Hi anatech,
here´s a review of CD-Check where the test signals are described.
On CD-Check, it is a 500hz tone overloaded with 20050hz.
http://www.audioxpress.com/reviews/media/cddr1review.pdf
Well, I have the OMS-5EII, so it is a three beam laser.
I am still looking for a replacement for the spindle motor (RF-310TB-11400)
RF-310TA works as well, but it is only available in a shaft length of 14 or 23,5 mm, at least in Germany, even though Mabuchi´s catalogue states a shaft lenght of 18,5 mm, which fits the Nak.
Did not want to cut the shaft, so I had a 5mm high spacer with an additional bronce bearing milled. Theoretically sturdier, the bearing starts to "sing" at 200 rpm. Damped the whole assembly with felt, but it did not help that much...
here´s a review of CD-Check where the test signals are described.
On CD-Check, it is a 500hz tone overloaded with 20050hz.
http://www.audioxpress.com/reviews/media/cddr1review.pdf
Well, I have the OMS-5EII, so it is a three beam laser.
I am still looking for a replacement for the spindle motor (RF-310TB-11400)
RF-310TA works as well, but it is only available in a shaft length of 14 or 23,5 mm, at least in Germany, even though Mabuchi´s catalogue states a shaft lenght of 18,5 mm, which fits the Nak.
Did not want to cut the shaft, so I had a 5mm high spacer with an additional bronce bearing milled. Theoretically sturdier, the bearing starts to "sing" at 200 rpm. Damped the whole assembly with felt, but it did not help that much...