Balanced Power

[Wavebourn]

No. Even though the isolation transformer and amp power transformer provide galvanic isolation for the power, the multiple grounds need to be connected all the way back to the AC outlet ground for safety. If your tube amp is constructed properly, the circuit ground will be tied back to the chassis ground, and so it will remain 0V.

Theoretically.
Practically wires have inductance and resistance so voltage drops caused by currents going through EMI filters and switched mode power supplies will be added. That's why professional gear have balanced ins / outs, the most expensive of it have nice audio transformers.

 

[leadbelly]

Theoretically.
Practically wires have inductance and resistance so voltage drops caused by currents going through EMI filters and switched mode power supplies will be added. That's why professional gear have balanced ins / outs, the most expensive of it have nice audio transformers.

That right, balanced interconnects and line level transformers are great. And as far as I can tell they have NOTHING to do with the originally posted question.