Your amp doesn't "send" watts anywhere. Nor does it even "make" 25 watts! That number, 25 wpc, is merely a reference based on a particular set of circumstances- typically (not always!) being specified as a load of 8 ohms, across a frequency range of (again, typically) 20 to 20kHz, after having been warmed up, and delivering the rated load continuously and as measured (typically, not always!) as the root mean square (RMS) of the sine wave amplitude.
The relevance of all this technical detail is in the fact that neither of your speakers is 8 ohms, at least not across their full response band, nor any of the other stuff. (Measurement standards now considered typical only started to become the standard right around that 1980 time frame!) Anyway, it all gets much worse when you try and drive TWO sets. Because then the power equation changes dramatically depending on how the speakers are connected- in series or in parallel. Two sets of nominal 8 ohm speakers can present a load of 4 ohms, or 16 ohms, series or parallel. Amps typically would measure twice (50 watts) at 4, half (12.5 watts) at 16.
In any case this is almost entirely academic. What matters in the real world is how it sounds. You will turn it up until either its loud enough, or distorted enough, to stop. Or maybe until it gets hot enough (or the load drops low enough) to trip protective shutoff. A lot of gear from back then (especially when sold with multiple speaker terminals) would have thermal and load protection.
The relevance of all this technical detail is in the fact that neither of your speakers is 8 ohms, at least not across their full response band, nor any of the other stuff. (Measurement standards now considered typical only started to become the standard right around that 1980 time frame!) Anyway, it all gets much worse when you try and drive TWO sets. Because then the power equation changes dramatically depending on how the speakers are connected- in series or in parallel. Two sets of nominal 8 ohm speakers can present a load of 4 ohms, or 16 ohms, series or parallel. Amps typically would measure twice (50 watts) at 4, half (12.5 watts) at 16.
In any case this is almost entirely academic. What matters in the real world is how it sounds. You will turn it up until either its loud enough, or distorted enough, to stop. Or maybe until it gets hot enough (or the load drops low enough) to trip protective shutoff. A lot of gear from back then (especially when sold with multiple speaker terminals) would have thermal and load protection.
