Re the possibility you mentioned of a tube integrated, keep in mind that a tube power amplifier (or the power amplifier section of a tube integrated amplifier) should NEVER be operated without a speaker load (or equivalent, in the form of a high power non-inductive resistor). That is particularly true if a music signal is going through the amplifier.
If you do want to consider a tube integrated amplifier, I would suggest choosing one that has both preamp out and power amp in jacks, so that you could operate it with no signal going into the power amp section. You could then attach a relatively low power resistor like
this one to each of the amplifier's two output channels, as a dummy load.
Regards,
-- Al