rms wattage for a model-t vs. 2000s

[Anonymous]

the rms wattage for a model-t is suposed to be 150w so a 2000s which has a simmilar tube compliment, 4-6550 at 500 to 525 volts, should too be a 150w amp, yet is only rated by sunn as 120w.  what would cause the  difference in wattage between the two, what is the true wattage for a 2000s?

[JoeArthur]

Output transformer primary impedance would be one candidate.  

The second would be the current capability of the power supply - even with identical voltages, the RMS power can be reduced if the constant current capability is less, which will also reduce the available voltage.

Remember, power is voltage times current.  Reduce either one and power goes down.  RMS power measurements sort of represent the maximum constant power the amp can put out.

[Anonymous]

thanks, that helps me to understand power ratings, whould you happen to know any general power transformer guidelines, like 410-0-410, refers to voltage correct? and what are some average current ratings for power transformers?, example: 200ma or 400ma. thanks again.