Unison Unico SE noise

I have had brand new tubes be bad right out of their box.

Arthur

Sounds like a bad tube to me, too, especially if the hum is in one channel only. It might just be a tube that needs to be reseated in the socket.

Whatever you do, use a step by step method. Consider swapping tubes from left to right, one pair at a time, and listen for changes.

the low level hum/static is in both speakers.

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?