[Quiet Earth]

It is no my opinion, as a fact all tube amps had more power avaliable in 16 ohms than in 8 or 4(Ohm law), but is not alot of watts.
Blair would inform us how much it is for his amp.

All tube amps is a lot of tube amps. All speakers is even more. I can't imagine we are talking about the same thing.

[Quiet Earth]

Roger probably knows more about tubes than all the rest of us on this circle combined.  Why not go to his circle and read his comments directly?

Ok, I read a little bit of that.

 I would not apply the light loading method as a general rule of thumb that works for all amps. For example, one thread explains how to run two positive taps at the same time without the ground wire (or zero return in this case) to make a 2 ohm tap. I would not recommend this as a universal  experiment on someone else's amplifier without knowing how it is made. Check with your manufacturer before you do this.  I'm sure that it's fine for Rogers's products, especially since he is the designer and he recommends that you try it. But even then, he asks you to listen and decide for yourself.

There is another thread I read where someone tried light loading and found the sound anemic, and then he had to move his speakers to recapture the body of the music. That implies (to me) that he was starving the output tranny to achieve a different sound quality that intrigued him. He was not improving the power transfer to his speaker.

And there is another exchange with Ralph Karsten of Atmosphere who specifically recommended that you do not light load an amp, because it is harder on the tube and the transformer.

I guess that light loading could be something that works in some cases, but I would not recommend it as a universal truth.

[FullRangeMan]

All tube amps is a lot of tube amps. All speakers is even more. I can't imagine we are talking about the same thing.

I will not venture to explain the Ohm Law, but Iam sure it applies to all electrical circuits, as tension, current, resistence and power are interrelated.
http://en.wikipedia.org/wiki/Ohm's_law

[Niteshade]

The speaker system is actually a component of an amplifier and not separate. Speakers complete an electrical circuit.

The relationship between power tube circuits and speakers isn't always clear and I will try to clear it up. What happens if you have a speaker that's 8 ohms connected to a 4 ohm transformer tap? It will increase the transformer's impedance from the tube's point of view. If an 8 ohm speaker is placed on a 16 ohm tap, the power tubes will see a lower impedance.

Think of it this way: With a multi-speed bike, you are the tube(s). If the front gear is small and the rear gear is large, pedaling is easier. The output transformer primary sees the outside world from the secondary. Light loading is like using a small front gear and a large back gear. Placing an 8 ohm load on a 16 ohm tap reduces plate impedance. A 8 ohm load on a 4 ohm tap increases plate impedance. It's all about winding ratios, which work the same as gear ratios. NOTE: An 8 ohm speaker on a 16 ohm tap is like using a large front gear and a small rear gear and the bike becomes difficult to pedal.

Speakers do not usually provide a linear impedance load to the amplifier. There are peaks and valleys. The valleys are what I'm concerned about. If you have an 8 ohm speaker which exhibits an impedance swing from 6 ohms to 12 ohms, the nominal tap will be 4 ohms, since it is closer to 6 ohms. The amplifier's feedback circuit will curtail voltage peaks that occur at higher impedances.

There is more to talk about. In a nutshell, speakers effect the entire amplifier back to the power supply. The impedance of a speaker is effected by it's enclosure and not just the voice coils and other electronics. One might even go as far as to say the room effects system impedance as seen by the amplifier.

[Ericus Rex]

And there is another exchange with Ralph Karsten of Atmosphere who specifically recommended that you do not light load an amp, because it is harder on the tube and the transformer.

I guess that light loading could be something that works in some cases, but I would not recommend it as a universal truth.

Another quote from Ralph found on Audio Asylum that seems to contradict this statement:

"I routinely run my speakers at home with only 4 output tubes. That will give you about 20-30 watts, depending on the load. It should be an easy load and this gets even better if the load is higher impedance like 16 ohms (that benefits almost any amplifier, FWIW...)."

[Quiet Earth]

I'll bet he was talking about the way he uses his own output transformerless amps. No transformer, so sure, that makes sense.