Medium gain power tubes causing buzz

[Love Rhino]

So I have a crack with speedball set up, and when using low gain power tubes such as a 6as7g there are no issues with pretty much a huge variety of driver tubes.  However, when I switch to a 5998 or 421A I get a buzz around the 9 pm mark on the volume control when using 6sn7 tubes.  I also get a background tap tap tap sound with the 5998 when using 12au7 which isn’t present with the 6as7g.

I’m trying to figure out where to start addressing this but could use a sign post .

Or I just use 6070 and 6as7g from now on!

[Paul Birkeland]

The tap tap tap would be noise from a cell phone or nearby wireless appliance.

[Love Rhino]

Thank you!  That actually makes a lot of sense, I have a wireless router not too far away that I can move.  I’ll see if that helps both the tapping and the buzz at mid volume.