Help!

One of my hi-fi speakers is making an odd hissing noise along with the bassline!

Apart from taking the wires out of the back and putting them back in, what can I do?

(I don't have the warranty because I found them in a skip)

Originally posted by kathythebean
Help!

One of my hi-fi speakers is making an odd hissing noise along with the bassline!

Apart from taking the wires out of the back and putting them back in, what can I do?

(I don't have the warranty because I found them in a skip)

Check to make sure that the cable for the speaker in question does not run alongside power cables as this could cause the issue.

Failing this, the only thing to really try is to ensure the cables are connected properly at both ends, and even try a different cable.

Originally posted by kathythebean
Help!

One of my hi-fi speakers is making an odd hissing noise along with the bassline!

Apart from taking the wires out of the back and putting them back in, what can I do?

(I don't have the warranty because I found them in a skip)

Are you playing an audio tape?

;)

Apart form noise originating from the signal source - e.g. a hissy tape and no Dolby, tone controls set to favour teh high end and such stuff, another possibility is that you've got some instability in the amplifier.

If it goes in sympathy with the bass, and you're running teh amplifier towards the edge of it's specifications (i.e. Spinal Tap Volume Control at 11) then the circuits can sometimes suffer from ultrasonic oscillation which manifests itself in the output as hissing or odd squeaking noises.

Does it stop hissing when you turn it down?

Does it hiss on headphones?

Joe

Ultrasonic oscillation eh? I suspected as much...

All the levels are the same as they always were and I'm playing the same CDs.

It doesn't hiss when I turn it down, and it gets louder when I turn it up.

I can't actually find any headphones to test it with.

Do you know if it's fixable, Joe? Thanks for your help btw.

Just check that the signal wires (i.e. the wires from the CD player to the amplifier) aren't running close to the loudspeaker wires.

Also, make sure that all the plugs are firmly in a frequent cause of 'odd' issues is an earthing problem If it's relatively suddenly started, have you moved the kit recently?

To see whether it was really caused by oscillation you'd need to look at the signal on an oscilloscope, but I'd start by just making sure the 'in' leads don't go near the 'out' leads, and also that the power leads are, as suggested, not close to either 'ins' or 'outs'.

If it is oscillation, and checking the wiring doesn't resolve it, it may be a failed decoupling capacitor. Fixable but tedious and potentially expensive in terms of time - nailing these things down can be time consuming.

It's a common problem in old valve kit, less common in modern gear unless the equipment has been stressed, has gotten damp, etc.

Joe