"Amp designs with push-pull or balanced topologies can achieve lower overall levels of distortion than single ended amps.

==The author (?) throw in balanced, but I don't understand how that benefits the distortion argument. The author jumps around a bit and creates as much confusion as he tries to clear. Further....

>>On the other hand, they achieve this overall distortion reduction chiefly by canceling out even order (2nd, 4th, etc.) distortion byproducts, which leaves behind a disproportionate share of odd order (3rd, 5th, etc.) distortion byproducts. "

==I don't see how this makes a case for either topology. I read the entire page and it's fairly rudimentary as far as describing various topologies. About the most meaningful statement is this,

"There are many schools of thought about distortion byproducts, with various psychoacoustic theories to support each"

and this...

"There are only a few exceptions, and these single ended amps deserve special praise for bringing overall distortion problems down to acceptable levels (though still detectable, and still higher than push-pull or balanced designs)".

>>In reality it makes no sense to me to argue topology. Fine examples of all kinds are out there. I am lucky to own several excellent kinds of every type of amp including SS and hybrids, otl and SE as well as arguably the worlds finest Pp-otl, the Berning 270. I also have a fine SE in the electronluv, I do prefer odd order distortions BTW. I have heard Lynn Olsens Aurora on my speakers and Paul Weitzels new SS amp, the Firstwatt, and my old Bogen PP. I really liked them all. But when it comes to my money of course SE wins, ultimately. It just sounds better, on my system/room.

To me it makes alot more sense to raise points about tangibles, like craftsmanship, implementations, parts quality and overall design. And what about overall system tuning and synergy between components like manualblock suggests????

Throwing an argumentive bomb to a forum is audio delinquency.

Manualblock makes sense with this regarding various topology debate:

====I have always thought this would be an important part of design theory except that the debate gets too silly with people re-stating the obvious ad nauseum. Or defending their point of veiw or their equipment like there was something at stake that reflects on them as people instead of just helping to advance the cause of better sound for the home stereo.
Or they have some odd or difficult to drive speakers that only sound good with one type of tube or something equally silly.
So when someone is genuinely interested in the musically relevant distinctions between the two circuit types it is side-tracked with all that nonsense.
Just an observation why there can't seem to be a rational dialogue.

>>Well said.

TC

I think you can make a much nicer sounding push-pull amp for a few hundred dollars than a SET amp, so I think entry level systems might be better off running push-pull. The trouble for DIY is that SET is simple to build but requires more expensive components for good sound quality. A good quality push-pull amp can be made with cheaper components, but it's more difficult to build, and maybe that discourages DIY builders.

I guess I've come to the conclusion that if you have the budget, give SET a go. There are some great SET amps in the >$2K range. Less than that, I'm thinking go push-pull.

BTW, I wanted to let you know that Akhilesh has a PhD and is a professor at Tulsa University, so he's a pretty quick study.

The phono stage application has a very small input voltage and comparatively( to power valve grid ) small output. This leaves it swinging a small proportion of its maximum. this looks to me to make the general topology a bit less important. Picture a traditional SE 2A3 ampllifier with a few tens of mV on the power stage grid. I think the distortion spectrum ( and overall amount as well ) would be of some characteristic shape fpr a properly loaded and driven 2A3.

On the 'SE Sound', I have heard a difference and was curious about moving towards quantifying it. I know my Class A PP amps don't have it...

Its why I made reference to battle, if that is brought to the front, perhaps thinking along those lines would help keep folks from typing frirst and thinking later. A few have made reference to that sort of thing, and there has been no unpleasantness as of this time( that I have read so far ).

more like looking for interesting and passionate discussion.
regards,
Douglas

It is not. Throwing a bomb into a pack of type-first/think later boneheads is only providing the catalyst to set them off. That they would explode is certain, and the when of it being the only unknown.

Suggesting that level headed grown-ups cannot discuss *ANY* topic under the Sun is an insult to those folks.

It's not like I wanted to know if somebody attended the 8:30 Service or the 10:30 one...or if it was on Saturday or Sunday.
regards,
Douglas

But let's think for a second outside the box (geez, I hate that phrase, but what the heck.) At equal volume levels (we all compare at equal levels, right?) what is the difference? I turn the volume knob up. Is there something going on in the gain stage that is being attribued to the amp itself? Does the preamp section sound different at higher gain than lower?

Even if all things are not equal, at equal volume levels, the SE is working MUCH harder, in relative terms, to push out the same loudness level. Is the SE being pushed into a more non-linear response, thus producing a differnt (better or worse) sound....Colin

But, if we use similar principles like in SE building - careful selection of linear tubes for the driver and output (DHT), class A operating point with carefully chosen high-quality OPT, LC-style PS with HQ oversized PT(s) (plus maybe additional heater/filaments transformers), MKP (non-electrolitic PS caps), no NFB loop, say - monobloc construction, phase splitter with real balance (CCS), etc. - we can really spend more for PP amp...but, I`m sure that the results will be worth it...

Sorry, wrong choice of words. Apologies to those folks.

TC

I am confident that if you remove budget constraints, you can make any of the popular topologies sound good. But if you make price/performance the goal, I think SET starts losing ground.

That may be why the budget models are probably better off push-pull. Whatever the case, the low end SET stuff just doesn't appeal to me. More expensive SET amps sure do though.