Here we go!
Did all the measurements!
* on pins 1 and 7 of IC 6673 and 6675 signals are absolutely identical at 1000 Hz
* on the KILL relay: well, tested 30 Hz, 60 Hz, 360 Hz, 1000 Hz, 6000 Hz: signals are identical for left and right, or at least there is no measurable difference!
* on the audio plug (before the cable!): no measurable difference between left and right
Before someone ask: I used the whole screen to measure, i.e. I set the lowest possible divison (or the greatest, depending how you see it!) to have a signal over the whole display! I use the store function to compare right and left, all the curves overlap perfectly. Of course, I changed time scale for the test tones to have 2 periods on the display...
As you all wanted me to have it done, I swapped the 1540: on the amp, right channel is still a little bit louder than the left. But nothing you/I can hear!
ps: had a very nice groundloop with scope connected to the cd, which was connected to the amp...
Did all the measurements!
* on pins 1 and 7 of IC 6673 and 6675 signals are absolutely identical at 1000 Hz
* on the KILL relay: well, tested 30 Hz, 60 Hz, 360 Hz, 1000 Hz, 6000 Hz: signals are identical for left and right, or at least there is no measurable difference!
* on the audio plug (before the cable!): no measurable difference between left and right
Before someone ask: I used the whole screen to measure, i.e. I set the lowest possible divison (or the greatest, depending how you see it!) to have a signal over the whole display! I use the store function to compare right and left, all the curves overlap perfectly. Of course, I changed time scale for the test tones to have 2 periods on the display...
As you all wanted me to have it done, I swapped the 1540: on the amp, right channel is still a little bit louder than the left. But nothing you/I can hear!
ps: had a very nice groundloop with scope connected to the cd, which was connected to the amp...
Maybe some of you will come to the conclusion that they should kill me...
I rechecked with a second cd player: the small difference between left and right is present here too. So, 2 options: the cd has difference between left and right or the vu-meters from my amp show little discrepancy (more probable!).
Conclusion: the CD303 seems to work fine now! There is no more disortion and no more output level differences between left and right!
I don't know how this disappear as I didn't solder or change anything in the player since last time I measured. At this time, there were no more distortions, but left and right channel where unbalanced (~20% difference!). Now it's all away. Don't know why. Would like to say that I don't care, but that whout be a lie! I would really really like to know how and why the unbalance disappeared!
Now another question: as the player is working and "seems" to have no problem, should I change the caps from the PSU are let the old ones in and have the job done when one cap will fail? What would you do?
Second question: as the 1540D, 7011, 7030 and another philips one are mounted on sockets and can be easily switched, is there any alternatives to them? Clearly, I don't need to change them, I would just like to see/hear something else, how the sound can be changed and in which way it could be changed! Any experience?
I rechecked with a second cd player: the small difference between left and right is present here too. So, 2 options: the cd has difference between left and right or the vu-meters from my amp show little discrepancy (more probable!).
Conclusion: the CD303 seems to work fine now! There is no more disortion and no more output level differences between left and right!
I don't know how this disappear as I didn't solder or change anything in the player since last time I measured. At this time, there were no more distortions, but left and right channel where unbalanced (~20% difference!). Now it's all away. Don't know why. Would like to say that I don't care, but that whout be a lie! I would really really like to know how and why the unbalance disappeared!
Now another question: as the player is working and "seems" to have no problem, should I change the caps from the PSU are let the old ones in and have the job done when one cap will fail? What would you do?
Second question: as the 1540D, 7011, 7030 and another philips one are mounted on sockets and can be easily switched, is there any alternatives to them? Clearly, I don't need to change them, I would just like to see/hear something else, how the sound can be changed and in which way it could be changed! Any experience?
Hello Attila,
As long as you have learnt something
Something was obviously going on for you to say the sound was distorted.
Here's what I would do. That earlier measurement - pin 4 was it, the "unclean one" Change the 22 mfd cap on that pin ( both channels ). That seems a definite discrepancy that occured, and caps do fail intermitently sometimes.
You are going to love this --- first use the player for a day or two to make sure it's OK and then swap the TDA's back. Why ? Because their is a "balance" adjustment preset that will be set for the original positions. Haven't looked to see what the correct set up is. If you plan on keeping the player I probably would replace the caps, but be careful, get ones that are physically as well as electrically the same. Nothing worse than seeing bent legs and wrong sized parts all over the place. You want it to look original. What I would definitely do is swap the NE5532 for something "better", if it were me I would try the OPA2604. Been very pleased with those, sonically superb. A lot will disagree and say use something more modern, but I find them excellent.
As long as you have learnt something
Something was obviously going on for you to say the sound was distorted. Here's what I would do. That earlier measurement - pin 4 was it, the "unclean one" Change the 22 mfd cap on that pin ( both channels ). That seems a definite discrepancy that occured, and caps do fail intermitently sometimes.
You are going to love this --- first use the player for a day or two to make sure it's OK and then swap the TDA's back. Why ? Because their is a "balance" adjustment preset that will be set for the original positions. Haven't looked to see what the correct set up is. If you plan on keeping the player I probably would replace the caps, but be careful, get ones that are physically as well as electrically the same. Nothing worse than seeing bent legs and wrong sized parts all over the place. You want it to look original. What I would definitely do is swap the NE5532 for something "better", if it were me I would try the OPA2604. Been very pleased with those, sonically superb. A lot will disagree and say use something more modern, but I find them excellent.
As it is now cured by opening it up and wriggling parts around, it sounds like the original fault could have been nothing more than a bad ground somewhere.
Push all socketed chips well in.
If you do go for upgrades , remember :- one at a time!!
Then you will know when and where something has gone wrong (if it does!)
good luck
Andy
Push all socketed chips well in.
If you do go for upgrades , remember :- one at a time!!
Then you will know when and where something has gone wrong (if it does!)
good luck
Andy
Hi Mooly!
No question, I learned a lot with this player! And thanks to your help and from the other posters here I could go thrue this and now have a working player!
The sound was heavily distorted! Resoldering the joints helped to cure this, but there was still the output problem! When listening to music, it was obvious that the right channel was not as loud as the left. Now eerything's fine... At least for now!
And no question again, I'll keep this player! No other one has such a nice touch! It looks magic in the dark, the way to go to the next track is special too. I love it, and maybe I'll get a second one! (another amp to feed!)
I'll change the cap, I just hope that I can find some that look exactly the same. For the psu caps: I'll go for change them, only problem is to find some with the same dimensions. From what I saw, modern caps with the same values are smaller... I don't want my player to look empty, or messy. Maybe nobody will ever see its inside, but I would know it... If you could give me some advices for the caps, it would be nice. Someone wrote not to use the expensive ones. Ok, clearly I won't use 20 euro caps for the psu, but 3 euro per cap shouldn't be a problem. I found some with very low esr values, saddly a lit bit smaller than the original ones, maybe they are an option...
The TDAs: well, now I know how easy it is to swap them I'll put them on their original place in a couple of days, depending on how much music I'll listen
NE5532: hmm, I then should use a socket for the case I want the original back. Have to see
To "modern": well, if I'd like modern, I wouldn't have repaired my CD303 and wouldn't have "so much" old amps Modern s not always good!
poynton: all chips were pushed down. It was the first thing I did after opening "the cage". Maybe that helped solving my problem. I think, I'll never know!
And don't wory, I'll do mods one at time!
No question, I learned a lot with this player! And thanks to your help and from the other posters here I could go thrue this and now have a working player!
The sound was heavily distorted! Resoldering the joints helped to cure this, but there was still the output problem! When listening to music, it was obvious that the right channel was not as loud as the left. Now eerything's fine... At least for now!
And no question again, I'll keep this player! No other one has such a nice touch! It looks magic in the dark, the way to go to the next track is special too. I love it, and maybe I'll get a second one! (another amp to feed!)
I'll change the cap, I just hope that I can find some that look exactly the same. For the psu caps: I'll go for change them, only problem is to find some with the same dimensions. From what I saw, modern caps with the same values are smaller... I don't want my player to look empty, or messy. Maybe nobody will ever see its inside, but I would know it... If you could give me some advices for the caps, it would be nice. Someone wrote not to use the expensive ones. Ok, clearly I won't use 20 euro caps for the psu, but 3 euro per cap shouldn't be a problem. I found some with very low esr values, saddly a lit bit smaller than the original ones, maybe they are an option...
The TDAs: well, now I know how easy it is to swap them
I'll put them on their original place in a couple of days, depending on how much music I'll listen NE5532: hmm, I then should use a socket for the case I want the original back. Have to see
To "modern": well, if I'd like modern, I wouldn't have repaired my CD303 and wouldn't have "so much" old amps
Modern s not always good!poynton: all chips were pushed down. It was the first thing I did after opening "the cage". Maybe that helped solving my problem. I think, I'll never know!
And don't wory, I'll do mods one at time!
Hi Attila,
Final thoughts then - most electroylitics have a standard "pitch" leg spacing. Usually 2.5, 5, 7.5, 10 mm etc. That's the thing to check. A lot of suppliers list the dimensions such as,
http://cpc.farnell.com/jsp/search/b...arch_003&Ntt=capacitor&Ntx=&_requestid=153437
Just go for well respected products like Panasonic, not unbranded or weird names. No need for anything exotic.
Changing the OpAmps I believe will give you the most significant improvement. Socket's are OK for playing around and trying different IC's but may in certain cases cause stability problems with any exotic ( very wide bandwidth ) devices. I always add a small cap in range 0.01 to 0.1 mfd soldered directly to the supply pins 4 and 8. Solder on the chip itself -- do it neatly and you can still use them in sockets if you want.
If you want a taste of something different ( much better IMO ) swap them for TL072 's and see what you think. Cheap and available anywhere and fine in sockets as they are. Try them !
Have fun with it all and any questions just ask
Final thoughts then - most electroylitics have a standard "pitch" leg spacing. Usually 2.5, 5, 7.5, 10 mm etc. That's the thing to check. A lot of suppliers list the dimensions such as,
http://cpc.farnell.com/jsp/search/b...arch_003&Ntt=capacitor&Ntx=&_requestid=153437
Just go for well respected products like Panasonic, not unbranded or weird names. No need for anything exotic.
Changing the OpAmps I believe will give you the most significant improvement. Socket's are OK for playing around and trying different IC's but may in certain cases cause stability problems with any exotic ( very wide bandwidth ) devices. I always add a small cap in range 0.01 to 0.1 mfd soldered directly to the supply pins 4 and 8. Solder on the chip itself -- do it neatly and you can still use them in sockets if you want.
If you want a taste of something different ( much better IMO ) swap them for TL072 's and see what you think. Cheap and available anywhere and fine in sockets as they are. Try them !
Have fun with it all and any questions just ask
This thread could be also of interest in this case:
http://www.diyaudio.com/forums/showthread.php?t=40682
http://www.diyaudio.com/forums/showthread.php?t=40682
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