Can all amps drive a 4 ohm load?

My pea-brained understanding of this matter is that, if your amp has tubes in it (I believe this one does?), that your amp will work harder to produce less wattage when connected to a "difficult" speaker load such as 4 ohms.
Solid state amps, on the other hand, will also have to work harder, but usually can provide more, not less, watts. With only 40 or 50 watts to work with, I think you'll want to find an efficient speaker, 89db or higher, with a simple 1st order crossover that won't slurp all your juice.

Cheers.

Cheers.

Tfkaudio....The tube amp will not work harder. In fact you need to use a lower tap on the transformer output just to have it work equally hard. This is like shifting to a lower gear in a car. You can go up a steeper hill, but you can't go as fast on the flat. The solid stare amp is more like a car with an engine that has a lot of torque, so you don't need to shift gears.

This amp is a hybrid with only one tube which goes in the preamp. The power section is solid state. Cheers, Josep