Speaker hiss

[hoshie]

afternoon folks!

just a small little problem ive had for awhile. I helped rebuild a 20yr old amplifier with a mate a month ago, its a Peak Solid-State Stereo Amplifier. Anyways, there are quite large amounts of speaker hiss evident - even at very low volumes! Judging by the amount of noise that comes out of them when nothing is playing, it sounds like they are turned up really loud when they aren't! Its becoming quite annoying, so does anyone know how to reduce speaker hiss? Clean the connections? What is causing this speaker hiss?

thanks!

[driload]

i suspect theres a snake colony curled up inside the Hydrosolator, next to the REcomatrint Matrix


reset the flux alignment to match that of the deploarised dilythium crystals and shout "wiggly wiggly wooo" and all should be fixed

[phunkdust]

driload you watch too much star trek

[Vital]

Maybe somewhere along the lines it's poorly earthed, hence the noise.

I wouldn't expect too much from a rebuilt 20 year old transistor amp though.

[kaossproject]

Check any capacitors.....or better still replace them all. Also check for dry solder joints.

Other than that I would say you are trying to thread too fine a needle with a shoe-lace.

[mungo]

Hiss as it is mostly generated by transistors and the way in which the amplify the signal. Being 20 years old the amp probably has few preamps all running at very high gains. Try tracing the signal from the start to find out where the noisy transistor(s) is. As a final idea run very hign input voltages and cut the gain in the middle of the amp, that may help.

[phunkdust]

hrm, 20 years ago the TL074's were just coming in as the new all-in-one preamp stage chip, they are pretty sturdy devices, they shouldnt cause much hiss, unless its one of the few amps around that time that was still running discrete pre stages...

see if you can read off the chip type in the pre stages

also would be handy if you could tell us the main amp stage chip type, ie multi transistor, monolitic, mosfet?

oh, and as kp said, check those capacitors. if you dont have a capacitance meter just start replacing suspect ones. capacitors (especially axial electrolytics) have a habit of dying after about 10 years of solid use...