Tube Watts vs. Solid State Watts - Any credence?

Another thank you, Bombaywalla!

For the most part, I've never much cottoned to ARC (or, CJ) products. As time moves forward, I tend to like the newer ARC products even less. Still, outside of the commentary OTL and a certain slant on the power supply, I came away more than impressed with how Mr. Johnson thinks and feels. Call it new found found respect.

Anyway, the contrarian part of my post is that a watt is NOT just a watt. We measure power under steady state conditions, using a resistive load. Music is anything but steady state, and despite Bud Fried's raison d'etre, loudspeakers are not at all resistive loads. Not to complicate matters too much, but loudpeaker (bass alignment AND crossover design) topology will greatly impact how much power an amplifier can put into it.

That said, all things equal, I've seen so many less powerful amplifiers put out more seat of the pants power than higher power amplifiers, and have come to the conclusion that the audio industry has not properly discovered how to measure actual / real-world / musical power. The most obvious example I can list is an 11 wpc push-pull 2A3 tube amplifier that thoroughly out-muscled the same manufacturer's 120 wpc hybrid tube / solid state product.

10-12-15: Trelja
Another thank you, Bombaywalla!

welcome Trelja.

10-12-15: Beavis
Are you trying to tell tube/solid state amps measure RMS differently?

Since Mapman has not answered till now & if I may be permitted to reply in his stead understanding what he is trying to say then.........
no, he's not saying that s.s. & tube amps measure RMS differently. That simply cannot happen - RMS is RMS no matter which amp.
i think he's saying the same thing Atma-sphere & I & others have already written which is: a watt is a watt but each amp reacts differently with each speaker. And, it is this interaction between amp-speaker that determines when & how much an amp will distort. This, in turn, will give the illusion in some cases that tube watts are more powerful than s.s. watts (they really are not).

I should have written that sentence differently pointing out that output power depends on the topology of the tube - triode vs. ultra-linear vs. pentode with the output power going progressively higher as one moves from triode to pentode.

Really it depends on how many tubes are used. Our MA-3 makes over 500 watts and its entirely triode, yet the H/K Citation 2 is pentode and only makes 60 watts. I think what you were trying to say in this passage is that pentodes **usually** pack a lot more power per tube than triodes usually do (there are triodes out there that make a lot of power; more than most pentodes).

Ultra-linear is a means of approaching triode linearity while retaining the power output of a tetrode or pentode (either can be used in ultralinear). The use of tetrodes, pentodes, triodes and ultralinear operation otherwise has nothing to do with power at all.

i think he's saying the same thing Atma-sphere & I & others have already written which is: a watt is a watt but each amp reacts differently with each speaker.

Actually I was more commenting on strictly how the amps distort- tubes interact favorably with human physiology while generally transistors do not (lower ordered harmonics as opposed to the dreaded 7th harmonic). This interaction can be quite profound and hard to turn down when you hear it!

A few years ago my band was at a show in Chicago. There were a lot of bands on the bill and to save time with each one shifting gear on stage, we offered to 'backline' our bass amplifier- a 400-watt Peavey ('backlining' is the process of having some equipment left on stage that all the bands would use during the show). One of the bands had a 500-watt Orange bass amplifier, which is class D. He wanted the extra power. He was quite blown away when I pointed out that a class D 500 watt amplifier would in no way keep up with a 400 watt tube amp on stage. He tried it and agreed- but had to go back to the class D amp as the Peavey made far more bass energy than he was used to- he was used to the thinner sound of the class D amp and was a little panicked that he would not be able to get the right sound (they were going on first).

Watts are not Watts. The reason tube amps have better Watts than solid state amps is pretty simple. It's because they generally have more dynamic headroom than solid state amps. Thus all things being equal tube amps won't clip as soon as solid state amps. Case solved.