PS Audio Linear Control Center and Phono III

[tomman888]

Hey all. I got this preamp yesterday and the phono stage totally outshined my Cambridge Audio 540P phono pre.

As for the Linear control center, well it's got issues. After a thorough clean-out with DeOxit on the pot's and controls, it has a low background hum (about 60Hz I guess).

Now I would automatically suspect the filter cap's but the transformer (EI core) is vibrating a bit. I think this is a part of my issue. I cannot tighten it though since it appears to be permanently bonded to the bottom of the pre's case.

Does anyone know where I should start with this? I have no prints or schematics on it.

 

[analog_sa]

Have a look at the supply rails with a scope. With the input shorted try to establish at what stage does the hum become visible. And also make sure there is no dc at output.

If you don't have a scope you will need to do some thinking or a lot of trial and error. Pictures?

 

[tomman888]

Apparently the problem was that the preamp was on top of my Furman line conditioner. It is dead quiet elsewhere.

But, considering how uninterested you all seem to be in it, I'll probably just get rid of it.