Mcintosh 2301 tube amplifier, how much power used from the wall?

I don't think the specs reflect what really happens. If it is that much it will heater room like a portable heater set to low Times two.

The only way to do this is to measure it from the wall.

What reaches the speaker is a minor part of the equation.

For example, the 600 W Mac amplifier only uses 60 to 70 watts when turned up very loud. 

I sniped this from ChatGPT:

The amplifier's power consumption varies depending on its operating conditions. Under typical usage, with normal audio signals and average volume levels, the MC2301 consumes around 800 watts of power per channel. Since it is a stereo amplifier, the total power consumption for both channels combined would be approximately 1600 watts.

If chatgbt is correct, that's absolutely horrifying.

That means this amp is equivalent to a full blown portable heating unit running continuously, and the heating units are about 1800 W on the high mode.

We are doomed!  Beware of AI

If the amp draws 5.5 amps at 120 volts then 660 watts is the most that can be converted to heat (energy is always conserved). That can mean, for example, you will need an additional 2,250 btu/hr for a room air conditioner just to remove the heat from the amplifier.

To get an exact number is tougher to calculate. The amp at idle will draw the bias current only, and that can be a value which is a fraction of the 40W plate dissipation. When the signal is going through the amp, the current is fluctuating and rarely goes to max plate current, so the overall heat dissipation can only be determined by monitoring the current draw over a given period of time (say, an hour). Then you can get a more precise number. If all you want to do is size an air conditioner then just use the rated amp draw, or use the nominal amperage of the mains fuse.