Reducing Noise

[Shawnobi]

Just finishing up the final jobs on my 5E3 build. I have some noise, which I would say is quite raspy. Increases as I turn up the tone pot. The other channel volume from which I am plugged into can reduce/ increase the volume as well.
Are there some 'best' techniques' for tracking the noise down? I am going to scope it from the input this week. But I do have a slightly differenct input arrangement where by I have a single input jack that uses just 2 inputs by way of a switch. So it's probably a bit more open to noise that a standard arrangement. But just need to improve to the best I can.

Thanks.

[trobbins]

Noise in amps may be associated with hum, and some of the techniques and appreciation are the same.

http://dalmura.com.au/projects/Hum%20article.pdf

[jmaf]

Do your heaters have a voltage reference to ground? What's the DC resistance between the heater pins and your chassis?

[Shawnobi]

Do your heaters have a voltage reference to ground? What's the DC resistance between the heater pins and your chassis?

Ah!
I believe the term is 'school boy error'... Amp is now so quiet I have to look at the tubes to see if it's on!

Thank you indeed.