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Old CD Players?
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Look for a player with one DAC per channel and an oversampling digital filter. The earliest Japanese players lacked the digital filter and used a high-order (brickwall) analog filter at the output of the DAC chip to reject ultrasonic noise. These filters sounded terrible due to their poor transient response and high phase shift in the top audible octave or two. Many of the early players also shared one DAC between the two channels because DACs were so expensive. This design approach introduced a fixed time shift between the two channels that was also detrimental to sound quality.
You may not want to hear this, but most reviewers felt that the best-sounding early CD players were either made by Philips in Europe or built using Philips technology. These were most often sold in the U.S. under the Magnavox brand name, though some were also branded as Philco, Philips or Sylvania. Philips had a 4x oversampling digital filter from the start and used one DAC per channel. Their earliest DAC chips were only 14-bit, though the oversampling increased their resolution to 16 bits, and their second-generation machines used a similar 4x oversampling digital filter with a 16-bit dual DAC (the TDA1541) that's still well respected today. The Philips players from 1982 into the early 1990s also had a unique disc drive design with a swing arm instead of a radial laser sled. One of these drives in good condition will track CDs and CD-Rs that would cause most other drives to skip or mute.
You may not want to hear this, but most reviewers felt that the best-sounding early CD players were either made by Philips in Europe or built using Philips technology. These were most often sold in the U.S. under the Magnavox brand name, though some were also branded as Philco, Philips or Sylvania. Philips had a 4x oversampling digital filter from the start and used one DAC per channel. Their earliest DAC chips were only 14-bit, though the oversampling increased their resolution to 16 bits, and their second-generation machines used a similar 4x oversampling digital filter with a 16-bit dual DAC (the TDA1541) that's still well respected today. The Philips players from 1982 into the early 1990s also had a unique disc drive design with a swing arm instead of a radial laser sled. One of these drives in good condition will track CDs and CD-Rs that would cause most other drives to skip or mute.
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"High Density Linear Converter" sounds like a catch-phrase from the marketing department. I don't know if the technology behind it sounds good, bad or mediocre. I recommend going with the dual DAC and an oversampling digital filter, preferably at 4x or higher.
I'm not a huge fan of 1-bit converters, but you won't run into those if you're looking at players from the 1980s. If memory serves, they started appearing in CD players in the early 1990s. The Philips "Bitstream" players with a 1-bit DAC running at 8x were noticeably poorer-sounding than their 16-bit/4x players of a few years earlier. The Panasonic MASH and JVC PEM low-bit converters sounded better than the Philips Bitstream chip set, though not quite as dynamic or detailed as a good oversampling multi-bit chip set.
One additional point ... the analog stage after the DAC can also affect the sound for good or ill. There was a thriving cottage industry in the late 1980s and early 1990s that improved mass-market CD players -- sometimes quite radically -- by changing op amps, upgrading the power supply and replacing selected passive parts with higher-quality ones.
canuckaudiog
On a quest for high fidelity
+1. I have a Philips CD-160 with a TDA1541 and the 4x oversampling rate. It's a very musical sounding CD player.. I love it.
Coastsider
Curmudgeon
Sony used dual Phillips TDA1541 DACs in their CDP-507ES which wasn't even one of their really high end players in the mid 80's. It's also a bit easier to find replacement Laser blocks as the same one in the 507ES was used in a number of other Sony models that can be bought cheap as doners.
Buzz
Active Member
Found some info on this. What do you think?
Sony's multi-level digital-to-analog conversion is a significant step forward
in audio technology. To appreciate the advance, it's important to understand
three types of digital-to-analog converters: multi-bit, 1-bit and multi-level.
Multi level D/A conversion
D/A conversion in a typical early CD player employed 16
switches, corresponding to the 16 bitsof the CD sample. Each switch
produced a different level of current, according to the significance of the
bit.
In the 1980s, the overwhelming majority of CD players used multi-bit
Digital-to-Analog converters (DACs). Also called "ladder type" or "resistor
ladder" converters, these designs typically used one resistor switch for each
digital bit in the sample. The value ofthe resistor controlled the amount of
current that flowed when the switch was On. Each switch produced current
proportionate to the value ofthe corresponding bit. For example, the current for
the Least Significant Bit (LSB) was 1, the next bit was 2, the next 4, the next 16
and so on up to the 16th or Most Significant Bit (MSB), which had a value of
32,768.
While these converters could offer superb dynamic range, they were
susceptible to a distortion called nonlinearity. For anygiven output level, the
combination of switches set On and Off would always be the same. In this way,
if a switch's current source had an error, that error would always be reflected in
the output level and the linearity would always be spoiled in exactly the same
way.
This problem of errors and nonlinearity was especially important in the
MSB, because the MSB is so big in comparison to the other bits (for example,
32,768 times the current of the LSB). Soeven slight errors in the MSB could
overwhelm the value of the smaller bits, distorting the musical signal at the zero
cross, where the binary digits flip from 1111111111111111 to 0000000000000000.
These errors are generally masked by the music, when it is loud. But when the
music is soft, this problem of "low-levelnonlinearity" can imparta grit or hardness
to the music that university researchers found to be audible.
For this reason, technologists developed 1-bit D/A converters that
bypassed the problem completely. Significant among these 1-bit designs was
Sony's own High Density Linear Converter™ circuit, which made its debut on the landmark CDP-X77ES in 1990 and has since been followed by Sony's Current Pulse 1-bit converter. Like other 1-bit converters, these Sony designs overcame the problem of zero-cross distortion, achieving superb low-level linearity for excellent sound, even during quiet passages and the reverberant tails at the end of musical notes.
guiller
Toscaninichus Australis
Where did you find this? It looks like a marketing speech at the time to me. I believe, as other have already express, that the 1-bit DACs were a step backwards (regarding sound quality ) when compared to the previous TOTL multibit DAC models.
Sony's description of its High-Density Linear Converter (TM) is typical marketing chatter describing a 1-bit DAC. While it's true that 1-bit converters can have better low-level linearity and better behavior at the zero crossing than multi-bit converters, it's also true that they have poorer transient response than multi-bit converters. That little fact didn't make it into the marketing blurb. The distortion mechanism is called slope-overload distortion. What happens is that the voltage or current step size in a 1-bit converter is small -- 1/32,768 of the full-scale voltage or current, assuming that the converter runs from -Vfs to +Vfs. If the input signal to the converter has a high slew rate, the converter can't add up its small steps quickly enough to follow the big change in the input signal, so it rounds off the transient.
There are ways to improve the transient response of a 1-bit converter. Panasonic used one of them in its MASH converter, which (IIRC) has a variable step size, so it acts more like a 4-bit converter running at 8x or faster instead of a true 1-bit converter. The other common approach is to increase the oversampling multiplier, running the 1-bit converter at 32x or faster rather than 8x, so that the time between voltage or current steps is reduced.
There are ways to improve the transient response of a 1-bit converter. Panasonic used one of them in its MASH converter, which (IIRC) has a variable step size, so it acts more like a 4-bit converter running at 8x or faster instead of a true 1-bit converter. The other common approach is to increase the oversampling multiplier, running the 1-bit converter at 32x or faster rather than 8x, so that the time between voltage or current steps is reduced.
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mhardy6647
Lunatic Member
The good thing about the vintage CD players is the build quality. The bad thing about them (in many cases; I'd argue in most cases) is having to listen to them.
bluesky
Lunatic Member
Used to have a mid 80s Sony. Can't remember the model number. It functioned perfect for 25+ years before it 'bit the dust'. It was really a good CD player, sounded fine too. Had a Denon too. It was a piece of junk.
New CD players really sound much better. It's astonishing really, and I don't even like CDs.
New CD players really sound much better. It's astonishing really, and I don't even like CDs.
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My experience has been that any player with 8X oversampling sounds very good out of the box, and if you upgrade the audio opamps and possibly the power supply caps, they sound as good as a new high end player.
Philips, Magnavox and Marantz players sound great but they use the older Philips CDM units which are no longer available and when they fail you have a boat anchor. I would not pay money for any old Philips unit. Some Sony lasers are no longer available, the KSS-151 and KSS-152, for example, so you have to be careful. Do your research when buying an older player. There are websites that tell you which laser and DAC was used. If you know of a player that sounds good to you, look up what DAC it uses and find another player with the same DAC and a Sony KSS-150A, KSS-210A, KSS-240A, KSS-213 laser. Those are currently available for $20 or less. Then when you buy the player, buy a spare laser.
Philips, Magnavox and Marantz players sound great but they use the older Philips CDM units which are no longer available and when they fail you have a boat anchor. I would not pay money for any old Philips unit. Some Sony lasers are no longer available, the KSS-151 and KSS-152, for example, so you have to be careful. Do your research when buying an older player. There are websites that tell you which laser and DAC was used. If you know of a player that sounds good to you, look up what DAC it uses and find another player with the same DAC and a Sony KSS-150A, KSS-210A, KSS-240A, KSS-213 laser. Those are currently available for $20 or less. Then when you buy the player, buy a spare laser.
Buzz
Active Member
Great info. My current Sony CDP-390 has a
TDA1543A DAC
KSS-240A Transport
So I think I am in good shape for the one player.
The lasers in those old Philips CDMs seldom go bad. The common failure modes are pretty well documented on the Net, and many of them are cheap and easy to address (such as the 33 uF axial-leaded cap in the CDM2/10 laser power supply or the flex cable that wiggles out of its clamp on the CDM2/10 drive). I wouldn't pay big money for an old Philips-built player, but I'd probably bite if one of them crossed my path at a reasonable price.
guiller
Toscaninichus Australis
Some further data regarding those Philips CDMs common failure reasons and more can be found here: http://lampizator.eu/LAMPIZATOR/TRANSPORT/laser/Laserology.html
Robinhawaii
Super Member
I really like my Audio Research CD2, not the best out there, but I can't really find anything to point out that is bad and it seems to still be holding it's value. Win, win 
Rob
Rob