What is Push-Pull?

pixellany · **Posted:** Apr Thu 19, 2012 11:37 am

Maybe anticlimactic, but-----two points.

1. I think most circuits are actually "push-push" (or "pull-pull"....). The tubes only conduct on part of the cycle, and each tube is operated in the same way.

2. "push-pull" describes a circuit configuration, and has nothing to do with how each tube is operated (A, AB, B, C, etc.) e.g. you could have a "push-pull" amplifier with both tubes running class A. (maybe dumb, but certainly possible.....)

For analogies, I think the 2-man saw is maybe the best. Does each man operate class A?---i.e. does he perform the same amount of work pushing and pulling? (I had always assumed it was mostly push and rest---ie. class AB or B)

Gary Tayman · **Posted:** Apr Thu 19, 2012 12:34 pm

Nick D. wrote:

Ugh....

You guys need to explain in layman's terms, not 'simpler' terms. I'll try to think of something.

There's a little guy inside your radio who sings his heart out. With push-pull, you have a duet.

:mrgreen:

ensignoftheunit · **Joined:** Apr Wed 18, 2012 1:10 pm **Posts:** 3

Gary Tayman wrote:

Nick D. wrote:

Ugh....

You guys need to explain in layman's terms, not 'simpler' terms. I'll try to think of something.

There's a little guy inside your radio who sings his heart out. With push-pull, you have a duet.

:mrgreen:

I like it.

But really, there have been some very good explanations, thanks for the help!

Does push-pull and single-end correspond to mono or stereo, or is that another ball game entirely?

Eickerman · **Joined:** Jan Fri 06, 2012 8:47 pm **Posts:** 2434

ensignoftheunit wrote:

Does push-pull and single-end correspond to mono or stereo, or is that another ball game entirely?

Stereophonic has 2 output amplifiers (1 for left channel sound, and 1 for right channel sound) rather than just 1 for monoaural (everything all together in a single sound channel). Each output amplifier can be either push-pull or single-ended.

Curtis Eickerman

kc2oso · **Posted:** Apr Thu 19, 2012 4:44 pm

This Amp was a fun build a few years ago. Parallel push-pull.

Man, 6V6's are expensive. I would up pilfering them for other projects.

Edit:

threeneurons · **Posted:** Apr Thu 19, 2012 5:38 pm

Single Ended:

Push-Pull, Class-A:

Push-Pull, Class-B:

But now his wife will never let him bring one into the house, because who's gonna clean up all the horse poo !?

Tube Radio · **Posted:** Apr Thu 19, 2012 6:06 pm

panther wrote:

People, please he said he was NEW to electronics. You are giving him explanations for someone with a very detailed knowledge of electronics theory. KISS.
Top/bottom half of the waveform, tubes are biased, the core can saturate, conduction over the full AC cycle, close matched, air gap, class A, class B, class A/B?????
Are these terms the best way to explain a paper clip to an alien ? Just explain it in simple terms rather, then try to impress the rest of the group. Really guys you are looking at the question through 20 to 30 years of practical experience. This poor guy is new and probably looking into a tube radio for the first time and doesn't even know what all the parts are yet.
Dan

I think it is good to give explanations as that will cause the OP to ask questions and give us the chance to explain what is meant.

If someone says something that goes over my head I simply ask and it gets explained to me and I understand.

tubeAMP · **Posted:** Apr Thu 19, 2012 9:36 pm

p/p also see differential output
one side amplifies neg one side amplifies pos
difference of peeks added together
more power
p/p output will run on one of the tubes
less power
best to have each p/p tube producing same current
best performance

codefox · **Joined:** Nov Sat 27, 2010 6:15 pm **Posts:** 3609

It's really divide and conquer. Ont tube pushes the top of the sine wave, and is relieved by the other tube taking up the other half. So in the end they can handle twice the power that each one could handle on it's own. The phase is split so this happens, and the result is handled in the output transformer which translates the pulses onto the secondary winding (fed to speaker) as well as passing direct curent to the plates (and it gets complicated with Mr. Williamson.)

Volumes have been written on it. Enjoy.

Pbpix · **Posted:** Apr Fri 20, 2012 3:43 am

On the serious side:
A very very simple explanation is to relate the push-pull function to that of a two-man saw.

Instead of one guy/gal doing all the work both men work synergistically to assist in the work.

On the humorous side:
A picture is worth a thousand Chinese dinners or something:

panther · **Joined:** Jan Thu 01, 1970 1:00 am **Posts:** 7416

Tube Radio wrote:

panther wrote:

People, please he said he was NEW to electronics. You are giving him explanations for someone with a very detailed knowledge of electronics theory. KISS.
Top/bottom half of the waveform, tubes are biased, the core can saturate, conduction over the full AC cycle, close matched, air gap, class A, class B, class A/B?????
Are these terms the best way to explain a paper clip to an alien ? Just explain it in simple terms rather, then try to impress the rest of the group. Really guys you are looking at the question through 20 to 30 years of practical experience. This poor guy is new and probably looking into a tube radio for the first time and doesn't even know what all the parts are yet.
Dan

I think it is good to give explanations as that will cause the OP to ask questions and give us the chance to explain what is meant.

If someone says something that goes over my head I simply ask and it gets explained to me and I understand.

I guess reverse engineering has it's good points. I though prefer building from the ground up.
Dan

pixellany · **Posted:** Apr Fri 20, 2012 1:16 pm

codefox wrote:

.....divide and conquer........

Best definition yet!!

markbark · **Joined:** Aug Wed 03, 2011 7:27 pm **Posts:** 327

markbark · **Joined:** Aug Wed 03, 2011 7:27 pm **Posts:** 327

Way too complicated. It was first spoken about in the movie" The Ten Commandments" and was the occupation of men who John Derick called upon to open the grain storage caves. Also briefly mentioned in instruction by the master of oars to the below deck slaves in "Ben Hur" . Seriously if a radio has two AF tubes is it, by nature "push-pull"? Often I'll read that the first tube being a is a multi purpose including an AF function,, the second the output tube

Eickerman · **Joined:** Jan Fri 06, 2012 8:47 pm **Posts:** 2434

markbark wrote:

Seriously if a radio has two AF tubes is it, by nature "push-pull"? Often I'll read that the first tube being a is a multi purpose including an AF function,, the second the output tube

Here is a comparison between a typical single ended audio section of a radio and a typical push-pull audio section of a radio. The Phase Inverter is necessary to drive the push-pull stage properly and can be accomplished with a tube or with a transformer. Signal flow is from left to right.

Attachment:

Compare.JPG [ 31.33 KiB | Viewed 148 times ]

Curtis Eickerman

What is Push-Pull?

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