Why so many tubes?


Many of the most expensive tube amps/preamp have multiple tubes...6, 8, 10. If direct path is preferred in the speaker by most, why the acceptance of a glass army in one's amp/preamp? 
jpwarren58
@jpwarren58

Not a troll thread at all. Seems like a complicated way to reproduce music.
please enlighten us, what would be a simpler way?

So some of tubes are the same as the power transformers?

https://splice.com/blog/vacuum-tubes-in-music/

https://www.electronics-tutorials.ws/transformer/audio-transformer.html

https://en.wikipedia.org/wiki/Valve_audio_amplifier

https://www.youtube.com/watch?v=Aj3LNHqUt3A

https://www.rs-online.com/designspark/building-a-valve-amplifier-part-1-design-components-and-layout

as you posted the original query, hope you have the patience to absorb the info above for some basic knowledge on the subject
Yeah but Ralph you are Da Man with stuff like this so I have to ask, what about going the other way? Why not use one great big high power tube? The reason I ask is some guys I respect are going that way with SET and real happy with it. Of course everything else still matters too but might there some inherent advantage to using fewer tubes?
Not really (if we're just talking about power tubes). All tubes are imperfect. So you run with one tube you deal with its imperfections. When you parallel a great number of them the differences tend to iron out and act more like the tube is supposed to in the data books. But you have a lot more current capacity so more power- without a distortion downside as long as the driver circuit can handle the grid capacitance of so many tubes. And that's not really a problem- we've been doing that for decades.

To give you an idea of how different the distortion figure can be, almost any SET when driven to clipping will make about 10% distortion (for this reason a good number of SET manufacturers spec the power at the 1% or 2% power level. rather than clipping). By comparison as an example, our M-60 makes between 0.5% to 1% THD at full power, but that power is 60 watts, compared to an amp that might be making only 8 watts. You can see that if the M-60 is then operated at the same power levels as the SET that its distortion will be much lower- probably 2 or 3 orders of magnitude lower (since both amps are zero feedback and their distortion decreases to unmeasurable as the power is decreased).


Distortion obscures detail, and it adds coloration since the ear interprets all forms of distortion as some sort of tonality. So even if the amp has a good distortion signature (which will cause it to sound smooth and not harsh) it simply will be unable to express detail in the way that an amp with the same but much lower distortion signature can.


So while the guys you know might be quite happy, that isn't the same as hearing everything out of their recordings that they could. One power tube is fun, it has a nice gothic steam punk appeal and SETs have a good distortion signature even though its quite high. But you can do better. 
The only problem I have with all this detail is you don't hear it like that in a live environment, maybe that's why people like set amps.