I’m not sure how tubes are rated, and am by no means a tube amp expert, but if you attach the tubes in bridged mode, instead of push-pull you could get 2x the voltage, or 4x the power. So assuming this is done, it seems quite plausible to me that you could get 60 watts RMS out of a pair of 33 watt (peak) tubes.
The proof is in the listening however. The difference in dB between 60 and 40 watts is only 1.76 dB. Point being, things look a lot more different in wattage than they sound.
The proof is in the listening however. The difference in dB between 60 and 40 watts is only 1.76 dB. Point being, things look a lot more different in wattage than they sound.