Loudspeaker designer/manufacturer John DeVore shows reviewer Ken Micallef his system.

That’s the common wisdom @jasonbourne71, but one of Modjeski’s goals in designing the RM-10 was to prove that it is not a fact but rather a fallacy. Modjeski and David Manley got into a heated debate in the pages of Stereophile on this very subject back in the 1980’s, I believe it was. Manley took the RCA tube manual literally, Roger unable to convince him that the manual was merely an application guide, not a tutorial on every tube's ultimate output potential.

If you read the technical reviews of the RM-10 by numerous publications, you will learn that the RM-10 does indeed produce 35 watts from a single pair of EL84’s per channel, and doing so with the amp operating in Class A for a portion of it’s output. That’s one reason DeVore chose it as his push/pull medium-power tube amp. Roger later made a special version of the RM-10 that was rated at 25 watts per channel pure Class A, again from a single pair of EL84s per channel.

By the way QUAD ESL owners, the RM-10 is a great amp for use with your loudspeakers. Unlike OTLs, the RM-10 has a low (for a tube amp) output impedance, so doesn’t interact with the insane impedance swings of the ESL the way OTLs do.

and the why is because RM was an excellent engineer and understood the very detailed RCA tube manual and SOA for that and many other tubes… MR products of which i’ve owned a few legendary for high performance with long tube life.

In this case doubt = wrong and very uninformed…. typical 

and RIP Sir. many who miss him.

@jasonbourne71: While doubting a pair of EL84’s can produce 35 watts, you failed to question a pair of KT88’s producing 125 watts. And yet Modjeski did just that in his RM-200 amplifier. For proof, read the test bench results John Atkinson got in Michael Fremer’s Stereophile review of the amp, in both original (100 watt rating) and Mk.2 (125 watt) iterations.

Few hi-fi tube amp designers have/had the depth of knowledge about vacuum tubes that Roger Modjeski did. Luckily a lot of his wisdom on the subject survives in the pages of AudioCircle (in the dormant Music Reference Forum). He designed his first amplifier (a single-ended triode) as age 6! He started repairing hi-fi electronics at a retail store while still in high school, and studied tubes for the rest of his life, visiting many tube manufacturing plants in England, Europe, and Eastern Block countries..

He then went to work for Harold Beveridge, the ESL loudspeaker designer/manufacturer. When that endeavor ended he started RAM Labs, RAM Tube Works, and finally Music Reference. His final product was a direct-drive ESL loudspeaker (no input transformer), the ESL stators and diaghrams driven directly by an OTL amplifier. WOW!

and don’t forget RAM Tubes with fantastic computerized curve testing against many critical to in circuit test points…. flunking out some 90% of current production tubes… still in business and i recall operated by @clio