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Re: Pull pin... [message #10965 is a reply to message #10963] Mon, 14 February 2005 13:42 Go to previous messageGo to next message
TC is currently offline  TC
Messages: 41
Registered: May 2009
Baron
>>For your benefit, please read the statement below:

"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



Re: Pull pin... [message #10966 is a reply to message #10965] Mon, 14 February 2005 13:50 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
Messages: 1275
Registered: May 2009
Illuminati (3rd Degree)
I agree with you: a well executed amp ofeithertype is better tto listen to than a badly executed one. The same can be said for solid state versus tube: a well executed solid state is better to listen to than a badly executed tube.
In fact, one can say that about any two design philosophies for any two components (single driver versus multi driver, etc etc) thereby making this entire debate (and in fact most discussions in audio land) moot.
-akhilesh

Still a bit of a generalization, but... [message #10967 is a reply to message #10960] Mon, 14 February 2005 14:01 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

I tend to agree. I've heard some really nice SET amps, but one thing I've started to realize is that they aren't cheap. The entry level SET kits I've heard had very little power and flabby bass or no bass at all. But if budget allows bigger tubes and iron, then I think SET becomes an attractive option.

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.



Re: Pull pin... [message #10968 is a reply to message #10966] Mon, 14 February 2005 14:24 Go to previous messageGo to next message
Manualblock is currently offline  Manualblock
Messages: 4973
Registered: May 2009
Illuminati (13th Degree)
Well AK; Moot is a strong word. I think there is validity in discussing these things as long as people refrain from attaching their own self worth to the outcome. With an open mind there is plenty to learn from each other.
And holding an opinion should be required by everyone who participates in any hobby. Thats why we do it.


sometimes.... [message #10969 is a reply to message #10964] Mon, 14 February 2005 14:33 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
things are as simple and straightforward as they appear.

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



No, absolutely not! [message #10970 is a reply to message #10965] Mon, 14 February 2005 14:40 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
From TC: Throwing an argumentive bomb to a forum is audio delinquency.

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


Good question [message #10971 is a reply to message #10955] Mon, 14 February 2005 15:10 Go to previous messageGo to next message
colinhester is currently offline  colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas
Illuminati (3rd Degree)
My main listening integrated is a Cayin TA-30. This can be run in either PP (30W) or SE (3.5W) just by pulling two tubes and re-biasing. Here we have a basis for EQUAL comparison. EQUAL source, parts, tolpogy, craftsmanship, etc.

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

Re: Still a bit of a generalization, but... [message #10972 is a reply to message #10967] Mon, 14 February 2005 15:18 Go to previous messageGo to next message
Damir is currently offline  Damir
Messages: 1005
Registered: May 2009
Illuminati (2nd Degree)
Hmm... When I try to compare "proper" (by my "standards", anyway:-)) way for making PP or SE amp, PP is more expensive...:-).
Yes, one can use 1N4007 bridge, 220uF electrolytic cap for the B+ (and say, another RC filter for the driver), with goal "everything cancels in OPT"... Then use simple (or low/medium quality) OPT, class AB, common pentode/beam tetrode (say EL34, KT88, or so), UL connection, NFB "loop" of 15 db or more... Then "ordinary" LTP phase splitter based on, say 12AT7 or so with 12AU7 "input" tube, etc.

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...

Re: No, absolutely not! [message #10973 is a reply to message #10970] Mon, 14 February 2005 15:32 Go to previous messageGo to next message
TC is currently offline  TC
Messages: 41
Registered: May 2009
Baron
Suggesting that level headed grown-ups cannot discuss *ANY* topic under the Sun is an insult to those folks.

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

TC

Re: Still a bit of a generalization, but... [message #10974 is a reply to message #10972] Mon, 14 February 2005 16:10 Go to previous messageGo to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

I agree with that too. Push-pull designs have more parts, so if all of them are expensive then that will be double the cost of a SET amp using the same parts. You've got a pair of output tubes and a splitter, more stuff. But some of the parts in a push-pull amp can be made smaller for the same power level as a comparible SET amplifier. Single-ended tube amps need bigger tubes and output transformers to get the same power.

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.


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