Crackling noise from left channel of my Arcam CD23

[andy2]

My cdp recently develops a static noise, almost similar to that of a tube amp, on the left channel, especially after extended use at high volume. Does anyone have a guess as to what part of the circuitry it may come from? Is it the output stage, or at the DAC stage? And where can I purchase the parts?

[Mooly]

Hi Andy... if extended use at high volume really is a factor then I don't see how the CD player can be suspect. The player works alone.

Have you eliminated the amp by swapping the amp inputs around.

If you mean the player develops this issue as it warms then it could be anything. If it is definitely on just one channel on the player output then it would appear to be DAC /digital processing related rather than analogue stages but without at least some basic scope checks then I wouldn't like to say.

[andy2]

Originally Posted by Mooly

Hi Andy... if extended use at high volume really is a factor then I don't see how the CD player can be suspect. The player works alone.

Have you eliminated the amp by swapping the amp inputs around.

If you mean the player develops this issue as it warms then it could be anything. If it is definitely on just one channel on the player output then it would appear to be DAC /digital processing related rather than analogue stages but without at least some basic scope checks then I wouldn't like to say.

On the same system, I have tried other CDP but there was no noise issue. I also swapped L/R the interconnects going from the Arcam to the preamp and the noise followed the channel.
The other odd thing is even as I turn the volume up and down on the preamp, I get some poping noise as well on the noisy channel. So it could be some interaction between the cdp and the preamp, but with other cdp in the system, I do not have any noise issue. My preamp is Conrad Johnson 17LS.
Thanks.

[Mooly]

It might be worth checking the DC offset of the CD player outputs. Should be 0.00v DC of course. An offset or some ultrasonic hash is the only thing I can think of that could make the CJ appear "noisy" when the volume pot is turned.

As ever, it really needs a scope on it to see what is happening.

[andy2]

Originally Posted by Mooly

It might be worth checking the DC offset of the CD player outputs. Should be 0.00v DC of course. An offset or some ultrasonic hash is the only thing I can think of that could make the CJ appear "noisy" when the volume pot is turned.

As ever, it really needs a scope on it to see what is happening.

OK, thanks for your inputs. I could try a pair of caps to see if it's the DC offset.

[Mooly]

If you have a DC offset or varying DC on the outputs then that is a fault. Adding caps isn't the answer.

[andy2]

Originally Posted by Mooly

If you have a DC offset or varying DC on the outputs then that is a fault. Adding caps isn't the answer.

I haven't gotten a chance to measure the DC offset yet, but looks like I might not have to because the noisy channel just decided to quit on me - there's very little sound out of the channel now

I'll try to open up the player and hopefully maybe it's a blown output opamp.

[Mooly]

Your first step has to be careful DC measurements on all the pins of the opamps. Compare each channel with the other.

[andy2]

Originally Posted by Mooly

Your first step has to be careful DC measurements on all the pins of the opamps. Compare each channel with the other.

OK, looks like a nice weekend project.