SOT : Can a PSU oscillate like this?

[lvs]

I have a Yamaha SY-22 synth - yay - got it second hand some years ago. When it's on, I hear a single tick coming from the speakers at (I think, didn't measure it I must say) fixed time intervals, say every five minutes or so. Strangely enough, I also have a pair of old active computer speakers that do a very similar thing. Question : can a very slow PSU oscillation be a possible cause of this?

Lucas

[amptramp]

I doubt anything in the PSU is designed to do this, although there could be some heat-related problems.

I suspect, from your description, that this is switching noise carried in from the household power lines.  It sounds like the sort of thing you get when a furnace switches on and off.  See if you can correlate it to something like that.  If you are not sure, try it in someone else's house and see if the same thing happens.

[lvs]

I suspect, from your description, that this is switching noise carried in from the household power lines.

Both the synth and the active speakers behaving like this, I was thinking that could be the cause, but eventually I feel it's not. The spikes I hear are also harder than the average switching noise on power lines btw.

See if you can correlate it to something like that.

Or it might be correlated to the fact the previous owner sold the synth too cheap to be true .

If you are not sure, try it in someone else's house and see if the same thing happens.

With the synth it does. As for the speakers, I haven't tried that but it's looks like a good idea since it might indicate their problem is actually a different one. Anyway I'm gonna try to find the cause in the speakers first - fiddling with those instead of the synth won't do much harm. Unfortunately I don't have a diagram of the synth.