Is that "low efficiency" of 30-50% really true?

Does that author bother to explain WHY he thinks that to be true?

No. That's why I was surprised enough to ask the newsgroup.


Given that pi-coupled class-C vacuum tube output stages commonly run
75% and higher efficiency, he's immediately proven wrong by example.

Good point!


I'm assuming that you haven't left out some important context from
the quotation...

It was only a half-page article in a small-format magazine in the first
place, and I did not leave out anything significant!


It would be interesting to hear why W8QUR thought to write that
statement about efficiency. It would also be interesting to know
if his article elicited letters-to-the-editor wondering about that,
back then.

We'll probably never know. That was 40+ years ago, and W8QUR isn't
in the online callbook, so it will be hard to ask him. At one time
I read the following issues and don't remember any comments or
corrections, but that was a long time ago!
--
--Myron A. Calhoun, W0PBV.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
NRA Life Member & Certified Instructor for Rifle, Pistol, & Home Firearm Safety
Also Certified Instructor for the Kansas Concealed-Carry Handgun (CCH) license