What are the height and width ?
If you increase the height and width, then it's fine to increase the depth as well.
You only get unpleasant resonances if it's too deep compared to the height and width.
Yes, you can make a push-pull class A amp.
You need at least two tubes.
The tubes are biased so they both amplify the whole waveform.
One tube amplifies the normal waveform.
The other amplifies the inverted waveform.
The OT combines the two signals so they add up properly.
Yes, you can make a...
Depends what you mean by clean.
A 20 watt amp will give you 20 watts of clean, but no more.
If you want more clean watts, consider solid-state, like a Fender Tone Master Twin, or a Quilter.
Also, if you have no particular volume requirement, then any amp will play clean if you keep the...
Used: Pretty much any boutique handwired Princeton
New: Any Fender PRRI with a 12" speaker, like these.
If you really care about $1100 vs $1000, call Sweetwater or GC and tell them it has to be $1000...
Also, point-to-point has a very specific meaning...
Those amps are apples and oranges (not comparable).
The Magnatone is a mono amplifier with a stereo vibrato.
There is no way to use stereo effects other than the vibrato.
The Swart is a true stereo amp.
Try a pair of AKG 240's ($100 or less).
They're relatively dull -- good to compensate for a bright amp.
But it's not about "studio headphones".
Studio headphones are accurate, like studio monitors.
The AKG 240's are dull, not accurate.