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SET the best?

Is SET amplification where we should all end up? I keep reading posts where people tell of their journeys from plenty power to micro power, and how amazing SET amplification is 45 set 211 set 845 set otl, and usually, ....with the right speaker. I have yet to read of anyone who has gone the other direction from SET, to High watt beast class A amps or others.
If your speakers can be driven by minimal wattage, is this the most realistic, natural sound we can achieve? versus say, 86db sensitive speakers and a 1000w amp?
Is the end result solely based on speaker pairing? circuit? tubes?

I am in the process of changing my direction in my search for realistic sound, just because, and wondering if this really is the best direction to be going.
From what I have been reading I think it may be.

What do we get with SET? What do we give up?

What's you favorite color?
hanaleimike
atmasphere's avatar
atmasphere
11,942 posts
 
Saki70, the speaker should be designed for tubes. See

http://www.atma-sphere.com/papers/paradigm_paper2.html

for more information.

I spent a few months tinkering with some 45-based SETs that I inherited last year. In analyzing the circuit, I realized some performance gains were possible through some simple mods and so got the amps to sound a lot better. Ultimately though I got curious what would happen if I made a P-P 45-based amp and did that as well (it makes about 4 watts and is class A). It was **instantly** better on the first attempt. IMO/IME most P-P amps are too complex and if a minimalist approach is taken SETs will not compete.
phaelon
1,052 posts
 
Hi Ralph,
I'm going to acknowledge, before I even ask, that this question is likely an example wrongful thinking.

Many people use tubes with speakers that were probably not designed with tubes in mind - in my case JM Lab Mini Utopias. My question is: Can a modification be done, perhaps to the crossover, that would result in the amp seeing a friendlier impedance curve?
phaelon
1,052 posts
 
For clarity, I'm asking about speaker mods only.
atmasphere's avatar
atmasphere
11,942 posts
 
Phaelon, SETs are usually not very powerful. A big one is 15 watts, maybe 20. If you really want to hear what they do, the speaker has to be efficient enough that you never bring the amp anywhere near full power.

At full power, the THD is often about 10%! At low power levels, the distortion might be unmeasurable, and what of it there is will usually be lower orders (2nd, 3rd and 4th). At high power the high orders become involved- that is the range of the amp that tells you not to turn the volume up any higher- it *sounds* loud due to to the presence of the 5th and 7th harmonics, which tell the brain how loud the sound is.

So the efficiency of the speaker is paramount and no matter what anyone tells you, to really hear what SETs do you need high efficiency: 97-98 at a minimum if your amp makes 15-20 watts. A 45-based amp needs a speaker that is more like 107 (if you really want to hear what it does anyway). This power limitation is one reason why I don't use SETs. The bigger you make them, the less bandwidth and detail.
phaelon
1,052 posts
 
Thank's Ralph. Does this apply to SETs specifically or to any low powered tube amp. The amp I'm considering is a 25W/ch 300b push-pull. That's Focal's lowest recommended rating for an amplifier to drive my speakers, but I've read advice (might have been yours) that those minimum w/ch recommendations always apply to solid state designs that increase their output as the impedance drops. That said, the amp that I have in mind is well made with pretty beefy transformers.
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