Hissing changes with input

[phase]

So I am getting a hissing that follows the inputs; as the inputs are switched, but cannot play both channels without one hissing, or occasionally silent if without a connected input.
The amp is an SAE2300, that I was thinking about recapping soon.I have a scematic.
The cables are very sensitive to handling while playing as well.

Any guesses as to what would this could be?

 

[rayma]

So I am getting a hissing that follows the inputs.

It might be oscillation. Is the noise gone when both inputs are shorted?

 

[Nanook]

a little off topic...

that would be my wife you're talking about...

seriously look at any op amps, and their supporting components.

 

[phase]

Thanks rayma, I was just looking at that, when I thought to check something else.
Well it happened to be that there was 1.75VDC coming out of the laptop headphone jack that I was using to test. Funny how its been just fine for the past five years, and just before I switched amps today.
When working with equipment that is nearly 40 years old, you want to suspect that and not the shiny laptop...
Nanook, I happened to get a bit of that here as well, must be going around...
The amp is playing now, and pretty nicely too I must say, better recap it soon before something goes off in a bad way.

 

[rayma]

there was 1.75VDC coming out of the laptop.

Unfortunately, a five year old laptop is likely to be on borrowed time.

 

[phase]

I suppose so, have a lot of good software on it too. I am going to have to get my DAC project going so I can use the usb output at least.
Am just very glad this didnt happen during one of the burn in sessions over the past month with another amp!