[SET Man]

Hey!

    I picked up a B&O CD-X CD player last year. The machine is in pristine condition. Although still works, but it need to be left on for awhile around 30 mins... likely those caps are going bad as expected for something that is now 37-40 years old. But at least it is good to see it working after warm up, a good sign.
   
   The reason I picked this up because I remembered when I was young I would see B&O and I've always love the way they look, even though they are not really a great performer for the price. And another reason is that I have a first generation disc player, the 1902 Victor Type E Talking Machine. So, I thought why not pick up a first gen CD player? Although the CD-X came out in 1985 weren't one the first CD player to hit the market, it was still using Philips' first gen CD transport the CDM-1 and first gen 14 bit DAC TDA1540 chip with 4X Oversampling. Ironically this machine doesn't have remote control!

    Anyway, I'm planning to restore the machine replacing all those caps in there. But I see there are mods and upgrades available like making it into operating in NOS mode, new Op-amps upgrades and etc. Now the question is... since I'll have to take it apart, should I just change those caps and keep it original as it was in 1985 or mod it make TDA154 into NOS mode?

   Honestly I'm leaning toward keeping original but at the same time I'm a fan of NOS DAC and the tinkering DIY side of myself want to mod it and see what it can really do. Well, let's see.

[viggen]

i just saw this video and hope it would help though it's not for a CD player but looks to be of similar vintage:

https://www.youtube.com/watch?v=HV6s2RHJfVk

i've always been curious bout the 1540 and would love a dac using that chip without the saa oversampling.  so, i'd love to see you rebuild it the way you like but somehow add a coax in haha.

[Nick B]

Hey!

    I picked up a B&O CD-X CD player last year. The machine is in pristine condition. Although still works, but it need to be left on for awhile around 30 mins... likely those caps are going bad as expected for something that is now 37-40 years old. But at least it is good to see it working after warm up, a good sign.
   
   The reason I picked this up because I remembered when I was young I would see B&O and I've always love the way they look, even though they are not really a great performer for the price. And another reason is that I have a first generation disc player, the 1902 Victor Type E Talking Machine. So, I thought why not pick up a first gen CD player? Although the CD-X came out in 1985 weren't one the first CD player to hit the market, it was still using Philips' first gen CD transport the CDM-1 and first gen 14 bit DAC TDA1540 chip with 4X Oversampling. Ironically this machine doesn't have remote control!

    Anyway, I'm planning to restore the machine replacing all those caps in there. But I see there are mods and upgrades available like making it into operating in NOS mode, new Op-amps upgrades and etc. Now the question is... since I'll have to take it apart, should I just change those caps and keep it original as it was in 1985 or mod it make TDA154 into NOS mode?

   Honestly I'm leaning toward keeping original but at the same time I'm a fan of NOS DAC and the tinkering DIY side of myself want to mod it and see what it can really do. Well, let's see.

What a nice find 👍 I would probably just change the caps and live with it for a while. You can do part 2 then whenever you like

[WGH]

... it was still using Philips' first gen CD transport the CDM-1 and first gen 14 bit DAC TDA1540 chip with 4X Oversampling.

But I see there are mods and upgrades available like making it into operating in NOS mode, new Op-amps upgrades and etc. Now the question is... since I'll have to take it apart, should I just change those caps and keep it original as it was in 1985 or mod it make TDA154 into NOS mode?

I would keep it original. I'm sure that B&O listened to both NOS and 4X oversampled and picked oversampled. Oversampling is not a bad thing, it is a cleaner way to filter out aliasing noise.


Surprisingly Google AI is right this time, most of the time it's only 50% right.

"Digital aliasing is a type of error that occurs when a signal is sampled at an insufficient rate, resulting in the misidentification of frequencies:

"Explanation
    "When an analog signal is digitized, it's sampled at specific points in time to create a digital copy. If the sampling rate is too low [14 bits in the TDA1540], the signal is undersampled, which can cause frequency components to be interpreted incorrectly. This results in the creation of false frequencies, or aliases, that weren't present in the original signal."


Ted Smith, PS Audio DirectStream’s lead developer wrote about the TDA1543 chip, which I would guess be similar and better:

"It’s [Philips TDA 1543 DAC] a very simple chip. For people who want NOS or R-2R style DACs it’s great. Also most people don’t seem to read the datasheet, the chip requires an opamp to meet its specs (which aren’t great), but many simply use resistors on its outputs which adds a lot of 2nd harmonic distortion and restricts the dynamic range.

"If your favorite music doesn’t have a lot of high frequencies and it doesn’t get too loud, the chip works well.

"Without an output filter the timing and waveshape of impulses is lost and PRaT will suffer, but if the original recording is already rolled off this won’t be a problem.
I suspect most people that really enjoy orchestral or, say, grunge [or rock] would be disappointed, but jazz trios, women’s solo voice, etc. should sound fine.”

[SET Man]

i just saw this video and hope it would help though it's not for a CD player but looks to be of similar vintage:

https://www.youtube.com/watch?v=HV6s2RHJfVk

i've always been curious bout the 1540 and would love a dac using that chip without the saa oversampling.  so, i'd love to see you rebuild it the way you like but somehow add a coax in haha.

    I like that Mend It Mark guy. Watched a few of his videos, very informative. I found  his video of fixing the PS Audio P300 after I recapped my P600, still it was interesting to see.
    Yeah, I'm tempted to make the CD-X into NOS while but I already have a a TDA1543 DAC in NOS mode. So, I'm still leaning toward keeping it original.

What a nice find 👍 I would probably just change the caps and live with it for a while. You can do part 2 then whenever you like

    I don't know if I want to take it apart twice though. But yeah, if my curiosity got the best of me I can do that down the road.

I would keep it original. I'm sure that B&O listened to both NOS and 4X oversampled and picked oversampled. Oversampling is not a bad thing, it is a cleaner way to filter out aliasing noise.

....

   It actually sound surprisingly pretty good as it right now with nearly 40 years caps in there. But I noticed the high can be a bit annoying and artificial to me though. I think the problem with the TDA1540 is that it is only a 14 bits chip and oversampling is to help it.

   I actually I have been using a simple TDA1543 in NOS mode since 2006... yes with just simple resistors. It is true that it doesn't do well in both extreme ends, but I do love the mid of this little DAC chip. I don't think I loss much of PRaT also. And I have compared it with a few DACs over the years including early ESS Saber chip, Topping D50(?) and Dendafrip ARES (original I think) and at the end I still like the simple TDA1543 better. And recently I built a tube buffer for it and now I feel that it is even better now.

   OK, I'll make plan to order parts for the B&O CD-X soon.
   

[John Tulett]

Nice vintage machine!
Although I don't know the history, after 40 years it's normal to find capacitors have aged.
Suggest first doing the capacitors replacement with good quality modern equivalents and see how it goes, you may like how it turns out.
Should your plans be to sell this B&O CD-X CD player one day, it may have more value restored to B&O's original specification.
Potential buyers looking to acquire genuine B&O equipment might shy away from modifications or upgrades not authorized by B&O.
On the other hand, if you have no plans to sell this vintage CD player and want to tinker, please share how it performs after modifying.
Whether it's just the capacitor replacements or other repairs, I wouldn't worry too much about having to take the unit apart twice, after the first time I'm sure you'll know what worked best for disassembly/reassembling.
 

[FullRangeMan]

Congratulations, its a elegant machine 
keep it original condition til it broke.

[SET Man]

Nice vintage machine!
Although I don't know the history, after 40 years it's normal to find capacitors have aged.
Suggest first doing the capacitors replacement with good quality modern equivalents and see how it goes, you may like how it turns out.
Should your plans be to sell this B&O CD-X CD player one day, it may have more value restored to B&O's original specification.
Potential buyers looking to acquire genuine B&O equipment might shy away from modifications or upgrades not authorized by B&O.
On the other hand, if you have no plans to sell this vintage CD player and want to tinker, please share how it performs after modifying.
Whether it's just the capacitor replacements or other repairs, I wouldn't worry too much about having to take the unit apart twice, after the first time I'm sure you'll know what worked best for disassembly/reassembling.

Hey!

    Well, I decided to keep it original. So, I will just recap it, put in new belt, fix the ground connections problem of which these machines are known to have. There's one mod that I decided to do though.... I'll be retrofitting it with a remote module kit. Yeah, I find it strange that this machine doesn't have remote while many cheaper players at that time come with remote.
   Anyway, I put it in my system and listening to it right now. After a long warm up both channels work. Amazingly this first gen CD transport from 1985 can read CD-R including the black CD-R discs!
   It actually sounds pretty good... no, it is not like a vinyl of which I prefer. But it is very enjoyable with very good mid. Personally I think Phillips was right about R2R type DAC chip but of course many Japanese companies went on to use Delta Sigma type DAC in the early '90s onward.
   OK, I've already ordered parts for this... I hope I won't @#2$&* this beautiful machine up! Wish me luck!