1084S-P audio, not sure if normal or issue.

[drojman]

Hi there,

I have the above monitor, new to me. I had to swap the flyback on it and it's now giving me a great image, however, I've noticed something with the audio which I'm not sure is normal for these or not.

Basically no matter if there's an audio source connected or not, there's a very audible hissing/rushing noise from the speakers. Audio itself is working fine and sounds good, no crackling etc, and responds normally to the volume control, however the background noise I describe does not. It's definitely related to the speakers, as if I disconnect them from the main board it disappears, which is also the case if I plug something into the 3.5mm jack.

My guess is this isn't normal, only because I also own a CM8833 MK2 and MK1 both of which doesn't exhibit this behaviour, but I'd love to confirm this or not before I go chasing it.

Thank you.

 

[petervg]

I just fired up my 1084S-P1 for you (also now hot+lotp since feb 2025) and with the volume potmeter turned to max without an audio source connected, it's dead silent except for a very very faint 50Hz hum (and some minor crackling noises when turning the potmeter).

 

[drojman]

Thanks for doing that, what you describe is the behaviour I observe in my other monitors. I have reflowed the audio board but no luck. I suspect the issue was present prior to me purchasing it because the audio board was disconnected when I took the shell off. Something obviously isn't quite right.

 

[MiaM]

This is just a guess but I think this can be the result of DC leakage through bad electrolytic capacitors in the signal paths. If you can't come up with anything better, I suggest doing a recap on any electrolytic caps that are anywhere after the volume control.

 

[drojman]

That's sort of what I'm thinking too, thankfully the board itself isn't massively complex. The power board itself is pretty easy to get to, so I might see about changing some of the caps there too.