Background Hum/Breeze/pink/white-noise

[Viktor]

But if you use a capacitor with lower capacitance on the nF scale you could cut out frequencies above for example 50kHz. With the one I tried (22uF) with any frequencies above 45Hz would be cut away if I understand correctly?
This was done by calculating the time constant based on the resistance of 22kOhms.

 

[Paul Birkeland]

If you're hearing the noise, and you cut it out with a capacitor, you will also be cutting out the signal at those frequencies. 

 

[Viktor]

Of course but I think it is safe to say my hearing does not go to 50kHz... 

Anyway I'll try it. Otherwise what do you suggest doing about the background noise?

 

[Paul Birkeland]

You may consider contacting a tube dealer regarding an ultra low noise 12AU7.