Power output of tube amps compared to solid states

Acrossley; Just to chime in, power is power period. and power is defined as IxIxR or VxV/R or VxI. In any case, power is related to resistance only. But speaker loads are not only made up by resistance only but what is called impedance that includes resistive loads and inductive loads and capacitive loads. So, when you see an amp spec'd at 50 wpc into 8 ohms, the manufacturer is stating clearly that this amp will produce 50 wpc from a particular input voltage (input sensitivity) into an 8 ohm resistive load. If they wanted to be clearer they would tell you what the power output is into an impedance (R+L+C) load at particular frequencies. but they will not do that. So, basically, what is on the amp specs is not what is really happening because your speakers are not resistive loads. So you are comparing apples to oranges. another example would be to take two 50 wpc into 8 ohm amps. One tubed and one ss. They both have a particular input sensitivity which will drive an 8 ohm resistive load at 50 wpc and typically that is measured with an input signal of 1khz. But, make that load a reactive (resistive, inductive and capacitive) load at 1khz at the same input signal level and you have an entirely different story. Or lower or increase the frequency with the same input signal level and no way will you see 50 wpc, unless you have a very well designed and built amp and let me tell you, you will pay a lot for that amp. Because it was designed and built correctly. I hope I didn't glaze your eyes. but every 50 wpc rated amp cannot drive the same loads the same because they were not designed to. The specs presented do not tell you everything. But, my point (long as it is) is that 50 wpc into 8 ohms resistive is the same, no matter what amp we are talking about. But the real loads your amps see are definitely not resistive and therefore the 50 wpc into 8 ohm spec goes out the window.

enjoy

Br3098, I appreciate the humor but seriously, the heat of our amps is quite manageable. Up here in Minnesota we see the highest dewpoints recorded anywhere worldwide and our amps are easy to live with even in the summer. However the heat comes from being class A, not the number of tubes. You can run the amp in Standby all day and at the end of the day, put your hand on the tubes without fear of burns. But from stone cold, within a minute the tubes are way too hot to touch because they are conducting.

IOW a solid state amp of the same power that is also class A will heat up your room in much the same way- it will make about 85% of the same heat. The real issue is, what do you want the system to sound like? Real music? If so, you are going to have to go class A- all other classes of operation are performance compromises.

Now it may be that you can find nice-sounding amps that are not class A, in fact they abound. But the very best, the ones that stand apart- they will be class A.

sorry for confusing, but i'm not speaking in terms of chaotic woofer movement. i'm speaking in terms of amount of pushed air from the woofer which is nothing else but sound.

I also absolutely agree and even sure that larger drivers are easier to control since they don't need to be moved excessively by the voice coil to have the same SPL, but would they 'dive down' to its designed lowest frequency with 30W is a pure question of speaker design and type of driver.
My friend received Wyred4Sound ST1000 instead of traded-in Quicksilver M60 and the lower end difference, overall control and sound delivery is 100% towards Wyred4Sound driving Aerial 10T. This 'gentle giant' really pushes the air from Aerials!
If anybody wants to challenge S30 next to Wyred4Sound on the true full range speaker such as Aerial 10t drop me a note. I'll be more than happy to A/B it with anybody local or currently local to NYC.

Arthur (Aball), I'd like to both thank and congratulate you on one of the most enlightening and informative posts I've encountered in my 10+ years here.

!!!! *** BRAVO *** !!!!

Perhaps Bud Fried's (a man who claimed he was born 25 years too early - I believe the true number was far higher) favorite anecdote was the one about the ship's captain who set both sail and his watch (at promptly 12PM) by the clock tower in the town square, and let everyone know the clock tower was the ultimate reference. One day the keeper of the clock tower was asked what method he used to keep the clock in time, only to answer, "Well, every day, day in and day out, precisely at noon, there's a ship whose captain sets sail at that very moment..." and I'm sure you can figure out the rest of the story.

Long ago, I came to the conclusion that the mantra "watts is watts" represented a most (among, if not, the most in audio) fundamentally flawed proposition. Though I've not invested the requisite time, effort, or thought into why, the fact that music is nothing like the steady state test tones that measurements are should make obvious how far off the path the numbers can lead us. It's simply the difference separating arithmetic/algebra from calculus, and I believe we're missing that point.

Most everyone in this field can (and does) measure the things that conflict with the ear, then go on to regurgitate what they read or were taught (yet do not understand) why we are mistaken because the numbers say so. Very few prove the ability to transcend all of that, as you have here, and can as I like to say, "question the answers and answer the questions" en route to actually UNDERSTANDING the topic at hand. That is the difference between a technician and a scientist/enginneer. Regardless of the job title, in my life, I've met precious few scientists/engineers.

Thank you again!