Kehut
The amp would only draw full rated current from the power supply if operates in Class A. All single ended amps are class A but few others are. Most operate in Class AB and draw much less current at idle than when driven.
I know from experience that power tubes in guitar amps have shorter life when routinely driven hard. I think the same will be true for high fi tube power amps, though the conditions in most hi fi amps are much less severe than in the average guitar amp.
The amp would only draw full rated current from the power supply if operates in Class A. All single ended amps are class A but few others are. Most operate in Class AB and draw much less current at idle than when driven.
I know from experience that power tubes in guitar amps have shorter life when routinely driven hard. I think the same will be true for high fi tube power amps, though the conditions in most hi fi amps are much less severe than in the average guitar amp.