Repairing an audio amplifier

[Nigel Goodwin]

No need for screened cables for speakers, or to spend stupid money on expensive ones - all you need is decent thickness wires, preferably stranded, as solid is hard to bend.

 

[roboticmisinfo]

"No need for screened cables for speakers,"

but would it be worth getting screened cable for the PC to amplifier?

 

[House0Fwax]

but would it be worth getting screened cable for the PC to amplifier?

Certainly, for the signal cable you need screened.

 

[Nigel Goodwin]

"No need for screened cables for speakers,"

but would it be worth getting screened cable for the PC to amplifier?

Not only worth it, but absolutely essential!.

 

[roboticmisinfo]

Yeah I can see why now. I'm just using a cheap cable at the moment. I'm pretty sure it's not screened, and there's a bit of noise there. I guess it's because the amplifier amplifies the noise, but after it's gone through the amplifier, noise can no longer be amplified (only added - if any at all) so speaker cable doesn't need to be screened. Got it... thanks guys,

Mike

 

[Nigel Goodwin]

Yeah I can see why now. I'm just using a cheap cable at the moment. I'm pretty sure it's not screened, and there's a bit of noise there. I guess it's because the amplifier amplifies the noise, but after it's gone through the amplifier, noise can no longer be amplified (only added - if any at all) so speaker cable doesn't need to be screened. Got it... thanks guys,

Pretty well, it's because the speaker signal is at a far higher level, and also a VERY low impedance.

 

[picasm]

I have the same model amp.
The speaker delay relay can cause some distortion. A while ago, mine occasionally sounded distorted for a few minutes after switching on. I cured it by carefully cleaning and re-tensioning the relay contacts.

By the way, I just use very thick twin mains type flex cable for the speakers, no need to waste money on overpriced special cables.

 

[roboticmisinfo]

Yes I get that problem too during the first few minutes. I put a song on which sounded distorted, then another which I new shouldn't have any distortion and that sounded a little distorted too. It seemed to stop after a couple of minutes though... I've got a big tube of about 60 relays at home... I wonder if any of those will fit. Mind you should I risk breaking it now that I have it working? :S lol

 

[picasm]

I've got a big tube of about 60 relays at home... I wonder if any of those will fit. Mind you should I risk breaking it now that I have it working? :S lol

No, I don't think you should replace the relay, just very carefully remove the plastic cover and gently clean the contacts - you could also spray them with a little contact cleaner fluid if you have some.
I had to also adjust the contacts slightly on mine because they were only just making contact, yours may not need that though.