Unison Unico SE noise

That doesn't sound like a tube issue to me. Have you tried unplugging all you sources, and re-connecting them one at a time to see if a source might be the cause? I'd try that, but connect only one source, then disconnect it and connect the next source. Once you've gone through them all, then you can start adding a second source. It might be a bad interconnect, ungrounded power cord, etc.

If you find the hum returns when a particular source is connected, then swap the source interconnects and power cord to rull out the wire as the problem.

Dumb question time - where is your ear when you hear this low level noise. In the listening position or at the speaker? If the latter you may just be hearing the noise floor of your amp or, more probably the noise floor of the particular tubes Wally installed.

There are tubes and then there are tubes teted for 'low noise'. A lot of tube electronics need LN tubes to avoid a low level sort of hiss. If you are only hearing this when your ear is next to the speaker, either forget about it or buy some especially low noise tubes.

BTW, do I assume that you listened for, and did not hear, this noise previously?

I tried unhooking all the interconnects. Even with all of them unhooked, the noise is still there.

Okay Newbee, I think you are right. I can't really hear the hum/static from my listening position. I have to get close to the speaker to hear it. I certainly do not hear it when the tv is on or when I am playing music. Thanks for the input so far guys.

Try using a cheater plug on your amp's power cord.

although there is noise from both speakers, it is really bad, loud in the right channel. It is a lot louder then when I first posted about the problem earlier. So I opened up the amp and switched the tubes from one side to the other. Sure enough the heavy static noise moved to the left side so that means it is a bad tube. These are the mullard CU 4003s (12AU7s). I know I need to replace the one tube, but my question is are the mullards a little noisey anyways?