Recording small amps driven hard, (can) sound(s) when played back, like big amps driven hard say 10 feet from your face on a stage.

The more energy you pump into a room the more mud you create within the room. So having a smaller amp with smaller speaker gives a better performance in a smaller room. Also, the tube saturation and slight speaker distortion are key characteristics of a lot of guitar sounds. So driving the crap out of an amp usually sounds better, but if the amp is massive then you better have a damn good, huge room.

You can settle for a thin tiny guitar sound, but if you know the hugeness is out there. Why not chase it?

Yep, the sound of a TUBE amp cranked is the result of many factors. You have the preamp tubes being driven hard, which adds some natural compression and distortion. You have the power tubes being driven hard, which does more of that. You have, possibly, "transformer sag" which is basically driving the output transformer into non-linearities that help contribute. You have the speakers being driven harder, which also creates their own particular characteristics...depending on the size, type, power rating, efficiency, etc.

A tube amp run lower will be cleaner sounding. And, there's nothing wrong with that. It's a usable sound...if that's the sound that fits. Just stick a mic in front, and adjust the recording level. A lower-level amp, or smaller amp cranked, will bounce around the room less than a large amp, cranked.

One thing to keep in mind is the perception of "loud" as related to power.

In general, it takes 10 times the power for a "perceived" doubling of volume. So, a 10W little sleeper tube amp has the capability of being about 1/2 as loud as a 100W Marshall. Which is plenty loud.

Of course, there's more to it than that. The speaker they are each plugged into makes a difference. One of those little 1W battery-powered cigarette-pack Smokey amps sounds pretty good through a 4-12 cab. Better than through it's tiny transistor-radio size speaker. Not loud enough for a band...but..it's 1W.

My Marshall was too loud for practice. As was the BF Bandmaster. Plus, they had not even reverb. My Blues Jr. was not quite loud enough. I settled for my Deluxe Reverb. From 100W to 38W to 15W...and settled for 22W. That was just enough that I could crank it most of the way to control it more from the guitar volume knob. More dirt...turn it up. Cleaner, turn it down. Doesn't take much.

And, yes, it may be hard to tell how loud an amp was after recording it. It could be a stompbox pummelling the thing at a low volume, though that may be easier to spot than...a POD, or a reamped direct track or something.

Bottom line is that to get a good, sweet, saturated tube-tone out of a tube amp...they like the volume cranked.

Kapt.Krunch

Tube rectifiers also contribute to this phenomenon.

When a tube rectifier experiences a high current draw it naturally lowers the voltage to the power amp, create a compression like effect to audio output.

So cranking up a tube rectified amp, you are adding a bit of compression to your tone.

Also the excursion of the speaker cabinets, the sweet area of volume (in dB) where they actually start to really move some air and perform in their power band, is a factor to good tone, as far as I understand it. This is why a 10" speaker is often preferable to a 12" for recording, as it can reach its sweet spot at lower volume.