Op amp replacements.

[Kotton]

What to replace to eliminate this amp hiss.
I have no idea what I'm doing or what I need to replace to eliminate the amp hiss on my sony str-de135, the hiss gets louder as the volume is turned up even with no signal, I read that it should be the op amps I have identified these chips but am not sure which to replace to eliminate the hiss or what to replace them with.

5218A

2103D

LC78212

I don't know what chip does what, though I do know how to solder, any help?
I need a chip that will at least replicate these when they were new without the hiss.

 

[benb]

Have a link to a schematic? It would help a lot, we could see where these are in the signal path, and what else is there.

 

[Mooly]

More info needed...

Does it hiss on all inputs ? I suspect that any hiss is going to be "normal" for this type of product as there is so much signal processing going on.

Full free manual,
Sony STR-DE135 | Owners Manual, Service Manual, Schematics, Free Download | HiFi Engine

I see the SNR is quoted as only 78db... not much better than a cassette deck with Dolby C.
By all means play with the opamps but it's not going to make it quieter.

 

[Kotton]

Didn't notice that before, xD Kind of disappointing) oh well Guess I'll use my t- amp to drive them and no more rear channel.