I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R it takes
20 seconds for the boom box to recognize the tracks and be ready to play it
after inserting the CD. With Memorex 52x, it takes only 2 seconds for boom
to recognize the tracks. Does it mean that Memorex is better quality? I
would have thought the gold coloration ;-) & Maxell name would make the
former a better quality?

Thanks.

-s

"Surinder Singh" wrote in message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R it
takes
20 seconds for the boom box to recognize the tracks and be ready to play
it
after inserting the CD. With Memorex 52x, it takes only 2 seconds for
boom
to recognize the tracks. Does it mean that Memorex is better quality? I
would have thought the gold coloration ;-) & Maxell name would make the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no burn
conditions.
The CD player has a calibration function that enables it to correctly
recognize these conditions.
Depending upon the design of the player, the ability to recognize disks with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD players to fail to
recognize CD-Rs, because insufficient range had been built into the
calibration function.

What you observe has more to do with the player than the disk.
Gold as a reflective material has a signficant advantage for archival use.
However, it is somewhat less reflective than aluminum.

It has to do with the reflectivity of the CD media. The older players were
not too sensitive to the characteristics of the disks you would burn on your
own burner. Most of the newer players manufactured today are very sensitive
to be able to play the home burned CD's.

On some of the older models, it is possible to force them to play the home
burned CD disks, by going in there and doing a re-calibration of the
player's alignment. In part of this recalibration, on purpose, the laser
current may be able to be increased a bit. Specialized tools, training, and
the service manual would be necessary to do this type of work. If the laser
current is increased however, its life span will be shortened, because it
was not designed to work at the higher intensity.

I found that the blue reflective coloured media type CD disks were better
for recording music to be played on standard CD players. I did some as long
as 3 years ago, left them in the car all of the time (through winter and
summer), and they still work very well.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Surinder Singh" wrote in message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R it takes
20 seconds for the boom box to recognize the tracks and be ready to play it
after inserting the CD. With Memorex 52x, it takes only 2 seconds for boom
to recognize the tracks. Does it mean that Memorex is better quality? I
would have thought the gold coloration ;-) & Maxell name would make the
former a better quality?

Thanks.

-s

With VERY few exceptions, audio CD players do not calibrate laser power
automatically. Some are adjusted with physical potentiometers, some newer
ones do it in a service mode using eeproms, but once set, the laser
calibration is done.
Focus is adjusted dynamically while playing, and of course during the focus
search routine. Focus offset value is kept in memory until the next disc
read operation so that if the PLAY button is pressed again, it can spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R it
takes
20 seconds for the boom box to recognize the tracks and be ready to play
it
after inserting the CD. With Memorex 52x, it takes only 2 seconds for
boom
to recognize the tracks. Does it mean that Memorex is better quality? I
would have thought the gold coloration ;-) & Maxell name would make the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no burn
conditions.
The CD player has a calibration function that enables it to correctly
recognize these conditions.
Depending upon the design of the player, the ability to recognize disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD players to fail
to
recognize CD-Rs, because insufficient range had been built into the
calibration function.

What you observe has more to do with the player than the disk.
Gold as a reflective material has a signficant advantage for archival use.
However, it is somewhat less reflective than aluminum.

Robert Morein wrote:


"Surinder Singh" wrote in message
.. .
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R it
takes
20 seconds for the boom box to recognize the tracks and be ready to play
it
after inserting the CD. With Memorex 52x, it takes only 2 seconds for
boom
to recognize the tracks. Does it mean that Memorex is better quality? I
would have thought the gold coloration ;-) & Maxell name would make the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no burn
conditions.
The CD player has a calibration function that enables it to correctly
recognize these conditions.
Depending upon the design of the player, the ability to recognize disks with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD players to fail to
recognize CD-Rs, because insufficient range had been built into the
calibration function.

What you observe has more to do with the player than the disk.

Bob - would the differences in CD player calibration that you describe be the
primary reason that, so I've been told by several, automobile CD players are
very much a gamble when using CD-R's?

As one who does a lot or home recordings from my LP/CD collection for use in a
"high-end' automobile audio system (Nakamichi, Audio Arts, MB Quart, Monster
Cable), I've avoided even considering an indash CD player and CD recording
essentially for that reason. I eoulfn't want to invest in a CD automobile
player which might or might not play CD-R's. Of course, as pointed out in the
other thread on "high-end" audiophile equipment, my automobile is the proud
posessor of a Nakamichi TD-1200 Mobile "Dragon" Cassette Deck/Head Unit
(installation was a chore, since this monster comes in 2 pieces - one just for
the electronics !) which is fed a steady diet of Maxell Metal C-90's encoded
with Dolby C and careful level settings recorded on a 3-head Nakamichi deck.
I've had these products for several years, and they are extremely rugged and
the performance is exceptional.







Gold as a reflective material has a signficant advantage for archival use.
However, it is somewhat less reflective than aluminum.










Bruce J. Richman

"Bruce J. Richman" wrote in message
...

Bob - would the differences in CD player calibration that you describe be
the
primary reason that, so I've been told by several, automobile CD players
are
very much a gamble when using CD-R's?

As one who does a lot or home recordings from my LP/CD collection for use
in a
"high-end' automobile audio system (Nakamichi, Audio Arts, MB Quart,
Monster
Cable), I've avoided even considering an indash CD player and CD
recording
essentially for that reason. I eoulfn't want to invest in a CD
automobile
player which might or might not play CD-R's.

I don't think that is an issue these days. My stock CD players
in both my Chevy and my Toyota have no problem playing CD-Rs.
Early in the days of CD-R burners, my first 4x burner that couldn't
reliably burn faster than 1x, I had some problems but not any more.
But just to be safe, take a CD-R to the dealer and try it.
I will point out that CD-Rs are a lot more sensitive to sunlight
than CDs. Leaving one on the dash will kill it in no time.

Of course, as pointed out in the
other thread on "high-end" audiophile equipment, my automobile is the
proud
posessor of a Nakamichi TD-1200 Mobile "Dragon" Cassette Deck/Head Unit
(installation was a chore, since this monster comes in 2 pieces - one
just for
the electronics !) which is fed a steady diet of Maxell Metal C-90's
encoded
with Dolby C and careful level settings recorded on a 3-head Nakamichi
deck.
I've had these products for several years, and they are extremely rugged
and
the performance is exceptional.

Did you ever look into dbx for cassette? Far superior to dolby IMO.

ScottW

Surinder Singh wrote:
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R it
takes 20 seconds for the boom box to recognize the tracks and be
ready to play it after inserting the CD. With Memorex 52x, it takes
only 2 seconds for boom to recognize the tracks. Does it mean that
Memorex is better quality? I would have thought the gold coloration
;-) & Maxell name would make the former a better quality?


No. it means your boom-box is crap quality. I have a Philips one like that
too. It only ever plays CD-R up to about 5 minutes, if at all.


geoff

Sorry, Mark, I can't agree.

The following tech sheet http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
.. Automatic follower operation (tracking gain and track detection level)

Because lasers wear and output decays over time, calibration to the
reflected signal at a particular point in the life in the product is
essential.

This feature is frequently referred to as AGC, and has been implemented with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is multi-read capable,
which means that it can read a CD-RW, which of all the available blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so good. It is
remarkable that Sony built multi-read into their products long before CD-RW
was in frequent use.

I have the service manual for all my players, and none of these older,
multiread capable units have either a calibration pot or a service mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not calibrate laser power
automatically. Some are adjusted with physical potentiometers, some newer
ones do it in a service mode using eeproms, but once set, the laser
calibration is done.
Focus is adjusted dynamically while playing, and of course during the
focus
search routine. Focus offset value is kept in memory until the next disc
read operation so that if the PLAY button is pressed again, it can spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R it
takes
20 seconds for the boom box to recognize the tracks and be ready to
play
it
after inserting the CD. With Memorex 52x, it takes only 2 seconds for
boom
to recognize the tracks. Does it mean that Memorex is better quality?
I
would have thought the gold coloration ;-) & Maxell name would make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no burn
conditions.
The CD player has a calibration function that enables it to correctly
recognize these conditions.
Depending upon the design of the player, the ability to recognize disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD players to
fail
to
recognize CD-Rs, because insufficient range had been built into the
calibration function.

What you observe has more to do with the player than the disk.
Gold as a reflective material has a signficant advantage for archival
use.
However, it is somewhat less reflective than aluminum.

I was talking CD-R, not RW, haven't tried those in the older Sony's but I
would be surprised. Lots of other units use the Sony pickups, and none of
them boost the laser power based on reflectivity - a constant current is
maintained as a voltage drop across a resistor, indicating a constant laser
diode current, regardless of reflected signal received back to the diode
pack. The APC (not ACG) transistor is mainly a switch, though as I say the
current is kept nearly constant.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Sorry, Mark, I can't agree.

The following tech sheet
http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
. Automatic follower operation (tracking gain and track detection level)

Because lasers wear and output decays over time, calibration to the
reflected signal at a particular point in the life in the product is
essential.

This feature is frequently referred to as AGC, and has been implemented
with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is multi-read capable,
which means that it can read a CD-RW, which of all the available blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so good. It is
remarkable that Sony built multi-read into their products long before
CD-RW
was in frequent use.

I have the service manual for all my players, and none of these older,
multiread capable units have either a calibration pot or a service mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not calibrate laser power
automatically. Some are adjusted with physical potentiometers, some
newer
ones do it in a service mode using eeproms, but once set, the laser
calibration is done.
Focus is adjusted dynamically while playing, and of course during the
focus
search routine. Focus offset value is kept in memory until the next
disc
read operation so that if the PLAY button is pressed again, it can spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R
it
takes
20 seconds for the boom box to recognize the tracks and be ready to
play
it
after inserting the CD. With Memorex 52x, it takes only 2 seconds
for
boom
to recognize the tracks. Does it mean that Memorex is better
quality?
I
would have thought the gold coloration ;-) & Maxell name would make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no burn
conditions.
The CD player has a calibration function that enables it to correctly
recognize these conditions.
Depending upon the design of the player, the ability to recognize
disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD players to
fail
to
recognize CD-Rs, because insufficient range had been built into the
calibration function.

What you observe has more to do with the player than the disk.
Gold as a reflective material has a signficant advantage for archival
use.
However, it is somewhat less reflective than aluminum.

"Bruce J. Richman" wrote in message
...
Robert Morein wrote:


"Surinder Singh" wrote in message
.. .
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R it
takes
20 seconds for the boom box to recognize the tracks and be ready to
play
it
after inserting the CD. With Memorex 52x, it takes only 2 seconds for
boom
to recognize the tracks. Does it mean that Memorex is better quality?
I
would have thought the gold coloration ;-) & Maxell name would make the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no burn
conditions.
The CD player has a calibration function that enables it to correctly
recognize these conditions.
Depending upon the design of the player, the ability to recognize disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD players to fail
to
recognize CD-Rs, because insufficient range had been built into the
calibration function.

What you observe has more to do with the player than the disk.

Bob - would the differences in CD player calibration that you describe be
the
primary reason that, so I've been told by several, automobile CD players
are
very much a gamble when using CD-R's?

It's plausible.
My buddy Larry has had an enormous assortment of players over the years.
Many of these were high end offerings that typically incorporate either a
Sony, Philips, or Panasonic mechanism. The capability varies widely.

I have had stunning success with Sony mechanisms. Even Sony portables can
play many, but not all CD-R's.
I suspect that the same ability may be found in Sony car audio.
If I were you, I'd burn several different blanks and take them to a store
for trial:
1. Verbatim (blue)
2. Maxell (clear)
3. Kodak
4. CD-RW

My main concern about car CD changers is what I percieve as the tendency to
damage disks. If product availability weren't such a problem, I'd consider
Minidisc.


As one who does a lot or home recordings from my LP/CD collection for use
in a
"high-end' automobile audio system (Nakamichi, Audio Arts, MB Quart,
Monster
Cable), I've avoided even considering an indash CD player and CD recording
essentially for that reason. I eoulfn't want to invest in a CD automobile
player which might or might not play CD-R's. Of course, as pointed out in
the
other thread on "high-end" audiophile equipment, my automobile is the
proud
posessor of a Nakamichi TD-1200 Mobile "Dragon" Cassette Deck/Head Unit
(installation was a chore, since this monster comes in 2 pieces - one just
for
the electronics !) which is fed a steady diet of Maxell Metal C-90's
encoded
with Dolby C and careful level settings recorded on a 3-head Nakamichi
deck.
I've had these products for several years, and they are extremely rugged
and
the performance is exceptional.







Gold as a reflective material has a signficant advantage for archival
use.
However, it is somewhat less reflective than aluminum.










Bruce J. Richman

Robert Morein wrote:
My main concern about car CD changers is what I percieve as the
tendency to damage disks.

??? Since 97 I've been running two GM automobile 12 disc changers
almost continously, each with at least 8-10 cdr's and I've never had 1
cdr go bad.

Robert Morein wrote:

Sorry, Mark, I can't agree.

The following tech sheet http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
. Automatic follower operation (tracking gain and track detection level)

Because lasers wear and output decays over time, calibration to the
reflected signal at a particular point in the life in the product is
essential.

This feature is frequently referred to as AGC, and has been implemented with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is multi-read capable,
which means that it can read a CD-RW, which of all the available blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so good. It is
remarkable that Sony built multi-read into their products long before CD-RW
was in frequent use.

My Denon I had ten years ago (bought new about 1992, IIRC) had no
problems, either. It did have an "amplified" mode so that if the
disc was reading poorly, it would basically double the sensitivity.
Another way around the problem. Never ever had it fail to read
a CD-R of any type.

"Mark D. Zacharias" wrote in message
...
I was talking CD-R, not RW, haven't tried those in the older Sony's but I
would be surprised. Lots of other units use the Sony pickups, and none of
them boost the laser power based on reflectivity - a constant current is
maintained as a voltage drop across a resistor, indicating a constant
laser
diode current, regardless of reflected signal received back to the diode
pack. The APC (not ACG) transistor is mainly a switch, though as I say the
current is kept nearly constant.

Mark Z.

I did not intend to imply that AGC is an adjustment of the laser diode.
It is an adjustment of the threshold detector.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Sorry, Mark, I can't agree.

The following tech sheet
http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
. Automatic follower operation (tracking gain and track detection level)

Because lasers wear and output decays over time, calibration to the
reflected signal at a particular point in the life in the product is
essential.

This feature is frequently referred to as AGC, and has been implemented
with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is multi-read
capable,
which means that it can read a CD-RW, which of all the available blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so good. It is
remarkable that Sony built multi-read into their products long before
CD-RW
was in frequent use.

I have the service manual for all my players, and none of these older,
multiread capable units have either a calibration pot or a service mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not calibrate laser
power
automatically. Some are adjusted with physical potentiometers, some
newer
ones do it in a service mode using eeproms, but once set, the laser
calibration is done.
Focus is adjusted dynamically while playing, and of course during the
focus
search routine. Focus offset value is kept in memory until the next
disc
read operation so that if the PLAY button is pressed again, it can
spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold CD-R
it
takes
20 seconds for the boom box to recognize the tracks and be ready
to
play
it
after inserting the CD. With Memorex 52x, it takes only 2 seconds
for
boom
to recognize the tracks. Does it mean that Memorex is better
quality?
I
would have thought the gold coloration ;-) & Maxell name would
make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no
burn
conditions.
The CD player has a calibration function that enables it to
correctly
recognize these conditions.
Depending upon the design of the player, the ability to recognize
disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD players to
fail
to
recognize CD-Rs, because insufficient range had been built into the
calibration function.

What you observe has more to do with the player than the disk.
Gold as a reflective material has a signficant advantage for
archival
use.
However, it is somewhat less reflective than aluminum.

And yet the laser power is not calibrated according to any disc
reflectivity, merely to provide a constant laser current, which is virtually
the same regardless of whether any laser light returns from the disc at all.

In a multi-read model, which I will admit I have not studied, this may be
different. Your old Sony however, isn't multi-read in the same sense as a
modern CD-ROM device. It may just have the laser power turned up somewhat.

The only unit I have seen which calibrated the laser output on playback was
a karaoke model - unknown Chinese vendor. Viewing the HF pattern on a 'scope
one could observe the laser "eye pattern" ramping up depending on the disc
type. Your Sony does not do this.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Mark D. Zacharias" wrote in message
...
I was talking CD-R, not RW, haven't tried those in the older Sony's but
I
would be surprised. Lots of other units use the Sony pickups, and none
of
them boost the laser power based on reflectivity - a constant current is
maintained as a voltage drop across a resistor, indicating a constant
laser
diode current, regardless of reflected signal received back to the diode
pack. The APC (not ACG) transistor is mainly a switch, though as I say
the
current is kept nearly constant.

Mark Z.

I did not intend to imply that AGC is an adjustment of the laser diode.
It is an adjustment of the threshold detector.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Sorry, Mark, I can't agree.

The following tech sheet
http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
. Automatic follower operation (tracking gain and track detection
level)

Because lasers wear and output decays over time, calibration to the
reflected signal at a particular point in the life in the product is
essential.

This feature is frequently referred to as AGC, and has been
implemented
with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is multi-read
capable,
which means that it can read a CD-RW, which of all the available
blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so good. It
is
remarkable that Sony built multi-read into their products long before
CD-RW
was in frequent use.

I have the service manual for all my players, and none of these older,
multiread capable units have either a calibration pot or a service
mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not calibrate laser
power
automatically. Some are adjusted with physical potentiometers, some
newer
ones do it in a service mode using eeproms, but once set, the laser
calibration is done.
Focus is adjusted dynamically while playing, and of course during
the
focus
search routine. Focus offset value is kept in memory until the next
disc
read operation so that if the PLAY button is pressed again, it can
spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold
CD-R
it
takes
20 seconds for the boom box to recognize the tracks and be ready
to
play
it
after inserting the CD. With Memorex 52x, it takes only 2
seconds
for
boom
to recognize the tracks. Does it mean that Memorex is better
quality?
I
would have thought the gold coloration ;-) & Maxell name would
make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no
burn
conditions.
The CD player has a calibration function that enables it to
correctly
recognize these conditions.
Depending upon the design of the player, the ability to recognize
disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD players
to
fail
to
recognize CD-Rs, because insufficient range had been built into
the
calibration function.

What you observe has more to do with the player than the disk.
Gold as a reflective material has a signficant advantage for
archival
use.
However, it is somewhat less reflective than aluminum.

"Bruce J. Richman" wrote in message


As one who does a lot or home recordings from my LP/CD collection for
use in a "high-end' automobile audio system (Nakamichi, Audio Arts,
MB Quart, Monster Cable), I've avoided even considering an indash CD
player and CD recording essentially for that reason. I eoulfn't want
to invest in a CD automobile player which might or might not play
CD-R's.

Thanks Richman for admitting that your luddite attitudes about home audio
have infested your car.

It's obvious that fear of change and hatred of new technology dominate your
decision-making process.

Please read my post again.
I said that AGC is a threshold detector function. It has nothing to do with
laser diode power calibration.
Sony players do nothing special with the laser diode. The AGC function
provides variable threshold detection, which is what gives it the ability to
read Orange Book.


"Mark D. Zacharias" wrote in message
...
And yet the laser power is not calibrated according to any disc
reflectivity, merely to provide a constant laser current, which is
virtually
the same regardless of whether any laser light returns from the disc at
all.

In a multi-read model, which I will admit I have not studied, this may be
different. Your old Sony however, isn't multi-read in the same sense as a
modern CD-ROM device. It may just have the laser power turned up somewhat.

The only unit I have seen which calibrated the laser output on playback
was
a karaoke model - unknown Chinese vendor. Viewing the HF pattern on a
'scope
one could observe the laser "eye pattern" ramping up depending on the disc
type. Your Sony does not do this.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Mark D. Zacharias" wrote in message
...
I was talking CD-R, not RW, haven't tried those in the older Sony's
but
I
would be surprised. Lots of other units use the Sony pickups, and none
of
them boost the laser power based on reflectivity - a constant current
is
maintained as a voltage drop across a resistor, indicating a constant
laser
diode current, regardless of reflected signal received back to the
diode
pack. The APC (not ACG) transistor is mainly a switch, though as I say
the
current is kept nearly constant.

Mark Z.

I did not intend to imply that AGC is an adjustment of the laser diode.
It is an adjustment of the threshold detector.



--
Please reply only to Group. I regret this is necessary. Viruses and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Sorry, Mark, I can't agree.

The following tech sheet
http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
. Automatic follower operation (tracking gain and track detection
level)

Because lasers wear and output decays over time, calibration to the
reflected signal at a particular point in the life in the product is
essential.

This feature is frequently referred to as AGC, and has been
implemented
with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is multi-read
capable,
which means that it can read a CD-RW, which of all the available
blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so good. It
is
remarkable that Sony built multi-read into their products long
before
CD-RW
was in frequent use.

I have the service manual for all my players, and none of these
older,
multiread capable units have either a calibration pot or a service
mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not calibrate laser
power
automatically. Some are adjusted with physical potentiometers,
some
newer
ones do it in a service mode using eeproms, but once set, the
laser
calibration is done.
Focus is adjusted dynamically while playing, and of course during
the
focus
search routine. Focus offset value is kept in memory until the
next
disc
read operation so that if the PLAY button is pressed again, it can
spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell Gold
CD-R
it
takes
20 seconds for the boom box to recognize the tracks and be
ready
to
play
it
after inserting the CD. With Memorex 52x, it takes only 2
seconds
for
boom
to recognize the tracks. Does it mean that Memorex is better
quality?
I
would have thought the gold coloration ;-) & Maxell name would
make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the burn/no
burn
conditions.
The CD player has a calibration function that enables it to
correctly
recognize these conditions.
Depending upon the design of the player, the ability to
recognize
disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD
players
to
fail
to
recognize CD-Rs, because insufficient range had been built into
the
calibration function.

What you observe has more to do with the player than the disk.
Gold as a reflective material has a signficant advantage for
archival
use.
However, it is somewhat less reflective than aluminum.

I think we're at cross purposes. Red Book doesn't define CD-RW as opposed to
CD-R, does it?

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Please read my post again.
I said that AGC is a threshold detector function. It has nothing to do
with
laser diode power calibration.
Sony players do nothing special with the laser diode. The AGC function
provides variable threshold detection, which is what gives it the ability
to
read Orange Book.


"Mark D. Zacharias" wrote in message
...
And yet the laser power is not calibrated according to any disc
reflectivity, merely to provide a constant laser current, which is
virtually
the same regardless of whether any laser light returns from the disc at
all.

In a multi-read model, which I will admit I have not studied, this may
be
different. Your old Sony however, isn't multi-read in the same sense as
a
modern CD-ROM device. It may just have the laser power turned up
somewhat.

The only unit I have seen which calibrated the laser output on playback
was
a karaoke model - unknown Chinese vendor. Viewing the HF pattern on a
'scope
one could observe the laser "eye pattern" ramping up depending on the
disc
type. Your Sony does not do this.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Mark D. Zacharias" wrote in message
...
I was talking CD-R, not RW, haven't tried those in the older Sony's
but
I
would be surprised. Lots of other units use the Sony pickups, and
none
of
them boost the laser power based on reflectivity - a constant
current
is
maintained as a voltage drop across a resistor, indicating a
constant
laser
diode current, regardless of reflected signal received back to the
diode
pack. The APC (not ACG) transistor is mainly a switch, though as I
say
the
current is kept nearly constant.

Mark Z.

I did not intend to imply that AGC is an adjustment of the laser
diode.
It is an adjustment of the threshold detector.



--
Please reply only to Group. I regret this is necessary. Viruses and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Sorry, Mark, I can't agree.

The following tech sheet
http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
. Automatic follower operation (tracking gain and track detection
level)

Because lasers wear and output decays over time, calibration to
the
reflected signal at a particular point in the life in the product
is
essential.

This feature is frequently referred to as AGC, and has been
implemented
with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is multi-read
capable,
which means that it can read a CD-RW, which of all the available
blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so good.
It
is
remarkable that Sony built multi-read into their products long
before
CD-RW
was in frequent use.

I have the service manual for all my players, and none of these
older,
multiread capable units have either a calibration pot or a service
mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not calibrate
laser
power
automatically. Some are adjusted with physical potentiometers,
some
newer
ones do it in a service mode using eeproms, but once set, the
laser
calibration is done.
Focus is adjusted dynamically while playing, and of course
during
the
focus
search routine. Focus offset value is kept in memory until the
next
disc
read operation so that if the PLAY button is pressed again, it
can
spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in
message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell
Gold
CD-R
it
takes
20 seconds for the boom box to recognize the tracks and be
ready
to
play
it
after inserting the CD. With Memorex 52x, it takes only 2
seconds
for
boom
to recognize the tracks. Does it mean that Memorex is
better
quality?
I
would have thought the gold coloration ;-) & Maxell name
would
make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the
burn/no
burn
conditions.
The CD player has a calibration function that enables it to
correctly
recognize these conditions.
Depending upon the design of the player, the ability to
recognize
disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD
players
to
fail
to
recognize CD-Rs, because insufficient range had been built
into
the
calibration function.

What you observe has more to do with the player than the disk.
Gold as a reflective material has a signficant advantage for
archival
use.
However, it is somewhat less reflective than aluminum.

I believe CD-RW is Orange Book.

"Mark D. Zacharias" wrote in message
...
I think we're at cross purposes. Red Book doesn't define CD-RW as opposed
to
CD-R, does it?

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Please read my post again.
I said that AGC is a threshold detector function. It has nothing to do
with
laser diode power calibration.
Sony players do nothing special with the laser diode. The AGC function
provides variable threshold detection, which is what gives it the
ability
to
read Orange Book.


"Mark D. Zacharias" wrote in message
...
And yet the laser power is not calibrated according to any disc
reflectivity, merely to provide a constant laser current, which is
virtually
the same regardless of whether any laser light returns from the disc
at
all.

In a multi-read model, which I will admit I have not studied, this may
be
different. Your old Sony however, isn't multi-read in the same sense
as
a
modern CD-ROM device. It may just have the laser power turned up
somewhat.

The only unit I have seen which calibrated the laser output on
playback
was
a karaoke model - unknown Chinese vendor. Viewing the HF pattern on a
'scope
one could observe the laser "eye pattern" ramping up depending on the
disc
type. Your Sony does not do this.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Mark D. Zacharias" wrote in message
...
I was talking CD-R, not RW, haven't tried those in the older
Sony's
but
I
would be surprised. Lots of other units use the Sony pickups, and
none
of
them boost the laser power based on reflectivity - a constant
current
is
maintained as a voltage drop across a resistor, indicating a
constant
laser
diode current, regardless of reflected signal received back to the
diode
pack. The APC (not ACG) transistor is mainly a switch, though as I
say
the
current is kept nearly constant.

Mark Z.

I did not intend to imply that AGC is an adjustment of the laser
diode.
It is an adjustment of the threshold detector.



--
Please reply only to Group. I regret this is necessary. Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Sorry, Mark, I can't agree.

The following tech sheet
http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
. Automatic follower operation (tracking gain and track
detection
level)

Because lasers wear and output decays over time, calibration to
the
reflected signal at a particular point in the life in the
product
is
essential.

This feature is frequently referred to as AGC, and has been
implemented
with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is
multi-read
capable,
which means that it can read a CD-RW, which of all the available
blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so
good.
It
is
remarkable that Sony built multi-read into their products long
before
CD-RW
was in frequent use.

I have the service manual for all my players, and none of these
older,
multiread capable units have either a calibration pot or a
service
mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not calibrate
laser
power
automatically. Some are adjusted with physical potentiometers,
some
newer
ones do it in a service mode using eeproms, but once set, the
laser
calibration is done.
Focus is adjusted dynamically while playing, and of course
during
the
focus
search routine. Focus offset value is kept in memory until
the
next
disc
read operation so that if the PLAY button is pressed again, it
can
spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary.
Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in
message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell
Gold
CD-R
it
takes
20 seconds for the boom box to recognize the tracks and be
ready
to
play
it
after inserting the CD. With Memorex 52x, it takes only 2
seconds
for
boom
to recognize the tracks. Does it mean that Memorex is
better
quality?
I
would have thought the gold coloration ;-) & Maxell name
would
make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the
burn/no
burn
conditions.
The CD player has a calibration function that enables it to
correctly
recognize these conditions.
Depending upon the design of the player, the ability to
recognize
disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD
players
to
fail
to
recognize CD-Rs, because insufficient range had been built
into
the
calibration function.

What you observe has more to do with the player than the
disk.
Gold as a reflective material has a signficant advantage for
archival
use.
However, it is somewhat less reflective than aluminum.

Well, if we're interested in continuing this mini-thread, if you don't mind,
let me just ask this, based on my recollection of an earlier post - does
your old Sony read CD-RW discs, as opposed to CD-R discs?

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
I believe CD-RW is Orange Book.

"Mark D. Zacharias" wrote in message
...
I think we're at cross purposes. Red Book doesn't define CD-RW as
opposed
to
CD-R, does it?

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Please read my post again.
I said that AGC is a threshold detector function. It has nothing to do
with
laser diode power calibration.
Sony players do nothing special with the laser diode. The AGC function
provides variable threshold detection, which is what gives it the
ability
to
read Orange Book.


"Mark D. Zacharias" wrote in message
...
And yet the laser power is not calibrated according to any disc
reflectivity, merely to provide a constant laser current, which is
virtually
the same regardless of whether any laser light returns from the disc
at
all.

In a multi-read model, which I will admit I have not studied, this
may
be
different. Your old Sony however, isn't multi-read in the same sense
as
a
modern CD-ROM device. It may just have the laser power turned up
somewhat.

The only unit I have seen which calibrated the laser output on
playback
was
a karaoke model - unknown Chinese vendor. Viewing the HF pattern on
a
'scope
one could observe the laser "eye pattern" ramping up depending on
the
disc
type. Your Sony does not do this.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Mark D. Zacharias" wrote in message
...
I was talking CD-R, not RW, haven't tried those in the older
Sony's
but
I
would be surprised. Lots of other units use the Sony pickups,
and
none
of
them boost the laser power based on reflectivity - a constant
current
is
maintained as a voltage drop across a resistor, indicating a
constant
laser
diode current, regardless of reflected signal received back to
the
diode
pack. The APC (not ACG) transistor is mainly a switch, though as
I
say
the
current is kept nearly constant.

Mark Z.

I did not intend to imply that AGC is an adjustment of the laser
diode.
It is an adjustment of the threshold detector.



--
Please reply only to Group. I regret this is necessary. Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Sorry, Mark, I can't agree.

The following tech sheet
http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller chip.
Among the features provided is
. Automatic follower operation (tracking gain and track
detection
level)

Because lasers wear and output decays over time, calibration
to
the
reflected signal at a particular point in the life in the
product
is
essential.

This feature is frequently referred to as AGC, and has been
implemented
with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is
multi-read
capable,
which means that it can read a CD-RW, which of all the
available
blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so
good.
It
is
remarkable that Sony built multi-read into their products long
before
CD-RW
was in frequent use.

I have the service manual for all my players, and none of
these
older,
multiread capable units have either a calibration pot or a
service
mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not calibrate
laser
power
automatically. Some are adjusted with physical
potentiometers,
some
newer
ones do it in a service mode using eeproms, but once set,
the
laser
calibration is done.
Focus is adjusted dynamically while playing, and of course
during
the
focus
search routine. Focus offset value is kept in memory until
the
next
disc
read operation so that if the PLAY button is pressed again,
it
can
spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary.
Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in
message
...
I play the CD's I burn in Phillipps Boombox. If I Maxell
Gold
CD-R
it
takes
20 seconds for the boom box to recognize the tracks and
be
ready
to
play
it
after inserting the CD. With Memorex 52x, it takes only
2
seconds
for
boom
to recognize the tracks. Does it mean that Memorex is
better
quality?
I
would have thought the gold coloration ;-) & Maxell name
would
make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the
burn/no
burn
conditions.
The CD player has a calibration function that enables it
to
correctly
recognize these conditions.
Depending upon the design of the player, the ability to
recognize
disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of CD
players
to
fail
to
recognize CD-Rs, because insufficient range had been built
into
the
calibration function.

What you observe has more to do with the player than the
disk.
Gold as a reflective material has a signficant advantage
for
archival
use.
However, it is somewhat less reflective than aluminum.

Yes, I have the following players that play CD-RW:
qty. 2 of CDP-202ES
qty. 1 of CDP-229ES


"Mark D. Zacharias" wrote in message
...
Well, if we're interested in continuing this mini-thread, if you don't
mind,
let me just ask this, based on my recollection of an earlier post - does
your old Sony read CD-RW discs, as opposed to CD-R discs?

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
I believe CD-RW is Orange Book.

"Mark D. Zacharias" wrote in message
...
I think we're at cross purposes. Red Book doesn't define CD-RW as
opposed
to
CD-R, does it?

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Please read my post again.
I said that AGC is a threshold detector function. It has nothing to
do
with
laser diode power calibration.
Sony players do nothing special with the laser diode. The AGC
function
provides variable threshold detection, which is what gives it the
ability
to
read Orange Book.


"Mark D. Zacharias" wrote in message
...
And yet the laser power is not calibrated according to any disc
reflectivity, merely to provide a constant laser current, which is
virtually
the same regardless of whether any laser light returns from the
disc
at
all.

In a multi-read model, which I will admit I have not studied, this
may
be
different. Your old Sony however, isn't multi-read in the same
sense
as
a
modern CD-ROM device. It may just have the laser power turned up
somewhat.

The only unit I have seen which calibrated the laser output on
playback
was
a karaoke model - unknown Chinese vendor. Viewing the HF pattern
on
a
'scope
one could observe the laser "eye pattern" ramping up depending on
the
disc
type. Your Sony does not do this.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Mark D. Zacharias" wrote in message
...
I was talking CD-R, not RW, haven't tried those in the older
Sony's
but
I
would be surprised. Lots of other units use the Sony pickups,
and
none
of
them boost the laser power based on reflectivity - a constant
current
is
maintained as a voltage drop across a resistor, indicating a
constant
laser
diode current, regardless of reflected signal received back to
the
diode
pack. The APC (not ACG) transistor is mainly a switch, though
as
I
say
the
current is kept nearly constant.

Mark Z.

I did not intend to imply that AGC is an adjustment of the laser
diode.
It is an adjustment of the threshold detector.



--
Please reply only to Group. I regret this is necessary.
Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...
Sorry, Mark, I can't agree.

The following tech sheet
http://www.sanyo.com/semiconductors/news/Vol66.pdf
gives specs on the Sayn LA9251M, a common CD controller
chip.
Among the features provided is
. Automatic follower operation (tracking gain and track
detection
level)

Because lasers wear and output decays over time, calibration
to
the
reflected signal at a particular point in the life in the
product
is
essential.

This feature is frequently referred to as AGC, and has been
implemented
with
varying degrees of effectivenss in different players.

For example, every Sony player I own, back to 1991, is
multi-read
capable,
which means that it can read a CD-RW, which of all the
available
blanks
differs the greatest from a pressing.

Most other brands were, at least in the past, not nearly so
good.
It
is
remarkable that Sony built multi-read into their products
long
before
CD-RW
was in frequent use.

I have the service manual for all my players, and none of
these
older,
multiread capable units have either a calibration pot or a
service
mode.



"Mark D. Zacharias" wrote in message
...
With VERY few exceptions, audio CD players do not
calibrate
laser
power
automatically. Some are adjusted with physical
potentiometers,
some
newer
ones do it in a service mode using eeproms, but once set,
the
laser
calibration is done.
Focus is adjusted dynamically while playing, and of course
during
the
focus
search routine. Focus offset value is kept in memory
until
the
next
disc
read operation so that if the PLAY button is pressed
again,
it
can
spin
immediately without doing another focus search.


Mark Z.

--
Please reply only to Group. I regret this is necessary.
Viruses
and
spam
have rendered my regular e-mail address useless.


"Robert Morein" wrote in message
...

"Surinder Singh" wrote in
message
...
I play the CD's I burn in Phillipps Boombox. If I
Maxell
Gold
CD-R
it
takes
20 seconds for the boom box to recognize the tracks
and
be
ready
to
play
it
after inserting the CD. With Memorex 52x, it takes
only
2
seconds
for
boom
to recognize the tracks. Does it mean that Memorex is
better
quality?
I
would have thought the gold coloration ;-) & Maxell
name
would
make
the
former a better quality?

Thanks.

Different CD disks have different reflectivities for the
burn/no
burn
conditions.
The CD player has a calibration function that enables it
to
correctly
recognize these conditions.
Depending upon the design of the player, the ability to
recognize
disks
with
different reflectivities vary.

Only a few years ago, it was common for many brands of
CD
players
to
fail
to
recognize CD-Rs, because insufficient range had been
built
into
the
calibration function.

What you observe has more to do with the player than the
disk.
Gold as a reflective material has a signficant advantage
for
archival
use.
However, it is somewhat less reflective than aluminum.

Mark D. Zacharias wrote:

Well, if we're interested in continuing this mini-thread, if you don't mind,
let me just ask this, based on my recollection of an earlier post - does
your old Sony read CD-RW discs, as opposed to CD-R discs?

Mark Z.

If your CD player can read a CDRW, then it's got quite strong laser
beam. CDRW are the hardest to read, then come CDRs, then the regular
audio CDs you buy at places like Tower Records. From my experience with
CDRWs, they are significantly harder to read than CDRs when you go from
player to player. If I make a CD, I want to know that it will play in a
CD boombox, my car stereo, my home player, etc, without difficulty. With
CDRWs, usually one of those items misses. Couple that with the fact that
they take longer to burn and cost more when compared to CDRs, I gave up
on CDRWs. I just burn CDRs as tests. Cost per CDR is cheaper than even a
TDK D90 normal cassette, so no biggie.

CD

"Codifus" wrote in message
et...
Mark D. Zacharias wrote:

Well, if we're interested in continuing this mini-thread, if you don't
mind,
let me just ask this, based on my recollection of an earlier post - does
your old Sony read CD-RW discs, as opposed to CD-R discs?

Mark Z.

If your CD player can read a CDRW, then it's got quite strong laser
beam.

It is not a question of beam strength.
Photodetectors can be incredibly sensitive, far more than required to sense
the reflection from a CD of any type.

The problem for the designer is to determine what level of reflectivity is
equivalent to a transition, and what level is the base reflectivity level.

This requires what is commonly referred to as an AGC circuit, though it may
go by different names. It determines the threshold that applies to the
particular disk.

Although this is a simple circuit, designers originally made AGC circuits
that could accomodate the range of various CD pressings. As the available
types of media diversified, AGC circuits were required to function over a
wider range.

Exhibiting an unusual degree of foresight, Sony CD players were equipped
with AGC circuits capable of handling media that would not be in common use
for years. Other manufacturers, particularly Panasonic, lagged developments
in media.

I need to give this a try on some old Sonys.

mz

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"WorldJAZZ" wrote in message
...

"Codifus" wrote in message
et...
Mark D. Zacharias wrote:

Well, if we're interested in continuing this mini-thread, if you don't
mind,
let me just ask this, based on my recollection of an earlier post -
does
your old Sony read CD-RW discs, as opposed to CD-R discs?

Mark Z.

If your CD player can read a CDRW, then it's got quite strong laser
beam.

It is not a question of beam strength.
Photodetectors can be incredibly sensitive, far more than required to
sense
the reflection from a CD of any type.

The problem for the designer is to determine what level of reflectivity is
equivalent to a transition, and what level is the base reflectivity level.

This requires what is commonly referred to as an AGC circuit, though it
may
go by different names. It determines the threshold that applies to the
particular disk.

Although this is a simple circuit, designers originally made AGC circuits
that could accomodate the range of various CD pressings. As the available
types of media diversified, AGC circuits were required to function over a
wider range.

Exhibiting an unusual degree of foresight, Sony CD players were equipped
with AGC circuits capable of handling media that would not be in common
use
for years. Other manufacturers, particularly Panasonic, lagged
developments
in media.

WorldJAZZ wrote:

"Codifus" wrote in message
et...

Mark D. Zacharias wrote:


Well, if we're interested in continuing this mini-thread, if you don't

mind,

let me just ask this, based on my recollection of an earlier post - does
your old Sony read CD-RW discs, as opposed to CD-R discs?

Mark Z.


If your CD player can read a CDRW, then it's got quite strong laser
beam.


It is not a question of beam strength.
Photodetectors can be incredibly sensitive, far more than required to sense
the reflection from a CD of any type.

The problem for the designer is to determine what level of reflectivity is
equivalent to a transition, and what level is the base reflectivity level.

This requires what is commonly referred to as an AGC circuit, though it may
go by different names. It determines the threshold that applies to the
particular disk.

Although this is a simple circuit, designers originally made AGC circuits
that could accomodate the range of various CD pressings. As the available
types of media diversified, AGC circuits were required to function over a
wider range.

Exhibiting an unusual degree of foresight, Sony CD players were equipped
with AGC circuits capable of handling media that would not be in common use
for years. Other manufacturers, particularly Panasonic, lagged developments
in media.


Nice. I wish my old Sony player was still functional. It would have been
nice to try out a CDRW on it. Anyhow, since CDRWs are still the most
finicky, these well adjusted AGC cicuits could only benefit someone who
buys all Sony CD players, one in their car, home, walkman, etc.

CD