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Tube power vs Solid state power, how much is enoug

Thinking about getting into tubes. My concern is how much is enough? From what I've seen, tube amp power is, on the whole, lower than solid state. I mean - ain't watts, watts? It's sort of confusing. Not being a big fan of non-dynamic (plannar, which there is nothing wrong with them, just not my cup of tea)speakers, I aim to wind up with either BW802, Legacy Focus/whispers, or the like. Unless I can find another way to achieve full range sound with a tube anp, I'll probably use(and really want to), my Krell with the tube, in a two amp configuration, driving one pair of the above mentioned units.

Shouldn't manufacturers just state voltage development or current ratings, instead of watts? Sure, more folks recognize the term watts, as it relates to power. But if it all comes down to how much voltage/current can be developed, and how quickly, then the term "watts", seems arbitrary. More so wehn you talk about "tube amps".

For the most part, I've long since quit looking at specs and just let my ears do the judging. That seems the best route. Problem with that is my ears usually end up arguing with my wallet, heart, and what is left of my brain. Some of these arguments are frightful. The winner is not always the ears. More times than not, the wallet wins. (not always), but usually. I try to leave the brain out of it as much as possible. Although, in this instance, I need to throw the brain a bone so I ask this question.

Just how do you figure out tube watts vs. solid state?

Please help my poor, ignored, seldom the winner, brain.

Thanks,
the brain
blindjim
gs5556
1,231 posts
 
You're looking at it backwards. It's not how much power is enough but how efficient the speakers are to produce the volume level you want. A highly efficient speaker, say 101 db per one watt/meter, will blast eardrums with only a couple of watts of power whereas a 86 db @ 2.8 V-m speaker will require a couple of hundred watts to be at the same level. It's like saying: how fast can I go with a 160hp engine - if it's on a skateboard, then very fast but if it's in a bulldozer, you won't move. Power is irrelevant unless you define the load it's driving.

If you want tubes and loud, look at high efficiency speakers. If you want a speaker that's not too efficient, go with higher powered tubes or solid state. A watt is a watt - but what a speaker does with it varies from make to make.
john_tracy
341 posts
 
Tube amps tend to clip 'softer' than SS amps. That is why you can play a tube amp as loud as a larger SS amp. Look at the distortion specs of both amps at full power and also the spectrum of that distortion. Generally the SS amps will come on strong with higher order odd harmonic components as they exceed full power. Tube amps generally have more harmonic distortion; but it builds more slowly and tends to be dominated by 2nd order even components. These are present in musical instraments and generally don't sound harsh or displeasing to the ear. Also, since they are already there in the music, it takes more for the ear to notice the increase. Whereas the higher order odd components tend to stand out and sound bad.
sean
6,231 posts
 
A watt ain't a watt ain't a watt. This is true even though it is supposed to be and there are set electrical parameters as to what constitutes a "watt".

Tubes and SS devices work on different principles. To put it in plain English, almost all SS designs are voltage limited whereas Tube amps are current limited. Some designs will work better with one type of amplification whereas that same amplifier may be completely lacking with a different type of speaker load.

I can explain why this is so if you folks are interested. Sean
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mechans
3,048 posts
 
I have very high efficiency speakers and there is more to it than that. Tubes generally fair better with a higher resistance load and are less prone to distort (impedance matching). Secondly the dynamics of the music change the load as you play and how loud you want to play changes the tendency for audible distortion. I have found that certain drivers within a speaker respond differently despite a nominal load as well. If your speakers have power-hungry woofers beware. Finally you should be very clear the power as stated in RMS wpc tells you only a small part of what an amps overall "power" is. The current capacity is very important. Since I am not an electrical engineer I can't tell you all you need to know, your ultimate test is to listen. Therefore Blindjim your choice of speaker and amp in combination is critically important. I use a 40wpc tube amp on lower 88db/W/M efficiency speakers (beauty) and a true 100 wpc solid state on very high efficiency speakers (beast) and get the effect I want from those two systems.
alex_yakovlev
102 posts
 
Sean, please do.
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