Electrical scratching sound from left speaker

[admin_exported]

Hi all,

A few weeks ago the fuse of the left channel of my Rotel power amp blew. I replaced the fuse. Ever since i have noticed that when i switch the amps off i can hear an "electrical scratching crackling sound" from the left speaker. I have now also heard it when switching tone controls on and off on the stereo amp. Have i damaged something else in either of the amps or the speaker?

 

[Anonymous]

I swapped the speakers cables around and now the sound comes from the right speaker, so that rules out any problem with the speakers. Must be something with the power amps left channel.

 

[Anonymous]

could possibly be something minor and maybe the amp just needs some deoxit on the pots ...

search google for deoxit and there are many sites which tells you how to use the stuff

 

[Anonymous]

it might be the volume control thats needs replaced.

 

[Anonymous]

there is a way to do a temp fix if the pots are dirty ... it's called scrubbing .... not sure how to do it,and remember reading about it on a forum ... dont think the volume pot need replacing, maybe just cleaning if this is the prob ...

on older gear, normally can be seen when you turn the volume control whilst playing music ... will make a scratching sound, but only does that when you turn the volume up or down

as far as I am aware, if one of the switches/control knobs are dirty, will also make a scratching noise until the amp warms up

 

[Anonymous]

its the power amp where the fuse blew so it might be worth taking that in to get it looked at as they usually dont blow without cause

if it were the volume pot youd hear the noise on both channels

 

[Dougal1331]

I would get the output stage capacitors checked- sounds to me like you may have one or more on its way out...

 

[Anonymous]

Thanks for all the advice guys. I've had the amps for less than a year so dust shouldn't be a problem and it only started doing it after i replaced the fuse. I know what caused the fuse to blow, a friend of mine switched the power amp on and off within a split second. The RB1080 is known to blow fuses when switched on and not left for a while before switching off. Would this cause problems with the capacitors? How would i test for this or is it best to leave it for technicians to check?

 

[Anonymous]

take it to a techie the problem could be a number of things

 

[Anonymous]

I disconnected the power amp from the stereo amp and connected the power amp to my Yamaha Z7 via the front preouts. No crackling sounds when switching Z7 on and off or adjusting controls etc. So maybe it's the stereo amp that has a problem.

 

[caddyhound]

Try changing the interconnects between Amp and Power amp,if the left channel one is breaking up internally it may cause these symptoms.

 

[Anonymous]

caddyhound:Try changing the interconnects between Amp and Power amp,if the left channel one is breaking up internally it may cause these symptoms.

I tried this and the crackling is still there. I contacted the Hi Fi shop where i bought the kit from, they are sending a courier to collect the amps from my house next week.