CD Player faulty output channel ?

Konzentr8

Member
2015-08-05 11:17 pm
Can anyone point me in the right direction as to cause of this ..... Sony CDP XB 720 E QS circa '98
Assuming all other possible causes have been eliminated by trial and error ( which they have ).
From cold after a day turned off everything is fine and the as it warms up the sound becomes noticeably quieter on the left channel. No distortion or cutting out etc just the volume imbalance .
Occasionally it will work all day with no issues and equal channel balance which makes it even more difficult to diagnose the cause.
Any advice or suggestions would be welcome.
 

Konzentr8

Member
2015-08-05 11:17 pm
Swap the left and right output leads, does it change sides?

Yes sorry forgot to say i had tried that and yes swopping output at the cd rca 's it changes from left to right .
I have eliminated everything past the cd player , cables ,amp and speakers have all been changed systematical and i have even set up in a different location to see if it was the room itself . Slowly driving me nuts .
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
Muting transistors leaky ? Remove them to prove the point.
 

Attachments

  • Capture.JPG
    Capture.JPG
    187 KB · Views: 32

Konzentr8

Member
2015-08-05 11:17 pm
Thanks for the help guys , problem now solved or more correctly identified .
Turns out theres not actually anything wrong with the Sony :/ In all the months i have been trying to find out the cause of the " problem " i never thought to change the cd player , this is my only source, but last night a friend gave me an old Marantz cd 4000 he no longer wanted.
Plugged it in for a test listen and exactly the same issue . Conclusion its not the equipment but my left ear appears to have a significant loss compared to the right :/ Now booked a hearing test to confirm .

With regard to the removal of the muting transistors ... worth doing anyway ? and can i just cut them out?
 

Konzentr8

Member
2015-08-05 11:17 pm
Thanks for the help guys , problem now solved or more correctly identified .
Turns out theres not actually anything wrong with the Sony :/ In all the months i have been trying to find out the cause of the " problem " i never thought to change the cd player , this is my only source, but last night a friend gave me an old Marantz cd 4000 he no longer wanted.
Plugged it in for a test listen and exactly the same issue . Conclusion its not the equipment but my left ear appears to have a significant loss compared to the right :/ Now booked a hearing test to confirm .

With regard to the removal of the muting transistors ... worth doing anyway ? and can i just cut them out?

Doesn't explain why swopping rca s round reverses things though my conclusion on that is its my imagination :)
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
Sorry to hear you think it might be your ears...... but I thought you had swapped leads and found the problem swapped sides :)

Removing muting transistors is something you would have to try. Personally I would leave them fitted as long as they are proved OK.

Although no home/on-line hearing test can be certified accurate you might glean something useful. Try this :

Free hearing test on line – Equal loudness contours and audiometry
 
Unless you are using headphones the effect of reducing one channel would be somewhat different from the effect of partial deafness in one ear. Swapping cables over would not affect your ears, for a start!

I think you need to review all the tests you did. Somewhere you didn't do what you thought you did. Easy to do this when under presssure.
 

Konzentr8

Member
2015-08-05 11:17 pm
I agree i did get really annoyed with the problem and think i ended up confusing things swopping components and cables etc . Problem is once our brains,well my brain is convinced of something ,imaginary or real,it tends to " lie " .
Thanks for the link Mooly .

I did a quick A-B this morning between the two cd players and both sounded quieter on the left channel so without messing around with cable / component swapping i'm just going to await the hearing test results for the moment .