The speaker/amplification wars continue

Take a breath!!

War!!  
No interest to us pacifists.

@mozartfan While I am also a fan of easy to drive speakers, regardless of your conclusion I really should point something out. The Defy 7 is a rather large amplifier and a 211 SET is not. In a nutshell if you want to know how PP does against SET, to start with maybe both amps should be the same power!

Another way to look at this is if you really want to know the difference between the two, how about eliminate some variables, like make sure both amps in the comparison use the same output tubes at least.

If you want to know weaknesses of SETs here are a few:

1) Because SETs make about 10% distortion at full power, if you really want to hear what they can do the amp should be driving a speaker that is efficient enough that the amp **never** makes more than about 20% of full power. This prevents the higher ordered harmonics from becoming audible; if they become audible it will be perceived as 'dynamics'. IOW the 'dynamic' character of SETs is caused by distortion and nothing else.

2) Obviously the speaker choice must be done carefully as outlined above. The output impedance of any SET is fairly high and the amp does not act as a voltage source, so your speaker choices are limited.


3) The higher the power of the SET the more its bandwidth is limited by the output transformer. This is true of PP too, but isn't really a problem until you are making over about 100 watts, as opposed to about 6 or7 with an SET. This is why the lower powered SETs like the 45s are preferred, but a 45 can only make 0.75 watts!

4) One advantage of SETs is that as you decrease the power the distortion goes down to the point that its unmeasurable. Distortion obscures detail; this is the source of the 'inner detail' that read about in so many SET reviews. But this property isn't limited to SETs, there are a number of PP amplifier topologies that allow this as well. 


5) You'd think an SET would have the simplest signal path but that isn't always the case. There are amplifier designs that have only 1 gain stage; SETs have 2 or 3. In an SET distortion is compounded from one stage of gain to the next in the amplifier. If you have a PP design and in particular if that design is fully balanced from input to output, you can cancel even ordered harmonics in each stage as the signal progresses through the amp. This results in dramatically lower distortion (smoother sound with more detail) even if feedback is not used.

I've yet to see a situation where an SET could sound better than a PP amp **when the variables are more controlled**. Its very safe to say its an antiquated technology which has been sidelined by succeeding arts.

Thinking about the unmeasurable distortion and incredible inner detail attracts me to SET. But then there are all these limitations and problems. Oh well. They do have a nice set of desirable qualities, for those willing and able to put up with the rest. 

Stream of consciousness belongs in modernist novels (Joyce, Faulkner, etc.) not in audio discussion posts.