Let's stop calling Class D amplifiers "efficient" when they are not.

[Petrushka]

So why not high bias class A for everything?

This is a high fidelity amplifier class. Class A amplifier's output transistors run at full power whether there's an input signal or not. When there's no signal, the transistors' power transforms into heat. When there is a signal, the power goes out the speaker terminals.

Also, each Class A output transistor amplifies both the negative voltage and the positive voltage parts of the signal's AC waveform, increasing the workload and raising more heat. Class A amps function at a 25% efficiency level and the remaining 75% of their power is turned into heat.

There are no turn-on, turn-off, warming, or cooling cycles that would affect the signal flow. In this class, you get distortion-free performance. Besides there is no switching going on, meaning there is no induced high-frequency interference. Pure Class A amplifiers are rare and expensive.

Difference Between Class A, AB & Class D Amplifiers Explained | Ooberpad

Know the difference between Class A, AB & Class D Amplifiers. Read more to understand how do these differences affect the efficiency & sound quality!

www.ooberpad.com

 

[Head_Unit]

I not talk about if a 5w tube or a 5w class d is more efficient.

The difference is not going to stop global warming, no.
However in battery powered application of many sorts, designers and indirectly users DO care about the efficiency.

 

[A.wayne]

Difference Between Class A, AB & Class D Amplifiers Explained | Ooberpad

Know the difference between Class A, AB & Class D Amplifiers. Read more to understand how do these differences affect the efficiency & sound quality!

www.ooberpad.com

Err, academic response not to the question.

Class A operation has superior sonics to the others, for headphones they make the best choice , class D is not for sonics but for high power @ reduced cost, size , etc ..

Same for class H , AB , B , these are all compromises to sonics based-on application where high biased class A is prohibitive ..

Class A is not best for high powered application , well not all ..


Regards

 

[SIY]

Class A operation has superior sonics to the others

Cite needed.

 

[A.wayne]

It’s Audiophilia we work with sights ...

 

[Jim Taylor]

Class A operation has superior sonics to the others

Class of operation has nothing to do with "sonics". Class A can be made to perform well or not, and the same for class A/B, G, H and D. If the designer is competent, understands the advantages and disadvantages, there is no problem. If the designer is incompetent or has willfully non-neutral leanings, then there is a problem .... and it will exist with each and every class of operation.
Many of the choices for amplifier designs today have to do with efficiency of manufacture as well as other considerations. Assembly line efficiency, educational level of the employees, embedded costs and long-term availability of parts are very important factors for companies producing all sorts of amplifiers. Business comes first and foremost, and many (if not all) of these companies have different priorities than we do.

Jim

 

[A.wayne]

Do i have to say it, we are talking absolutes not strawman every chink in armor content...

Specifically sonics.

 

[Jim Taylor]

Class D is most efficient because after 5 mins you Turn them off and walk away ..!

It’s Audiophilia we work with sights ...

Do i have to say it, we are talking absolutes not strawman every chink in armor content...

Specifically sonics.

You are not making sense. Your profile doesn't indicate your country of origin, but if I had to guess, I'd guess that English is not your native language. In order to translate more accurately, and possibly maintain a grasp of idiom, please try this translation app:

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Jim

 

[DonH56]

It’s Audiophilia we work with sights ...

There's my problem, all these years I've been using my ears.

 

[tomtoo]

The difference is not going to stop global warming, no.
However in battery powered application of many sorts, designers and indirectly users DO care about the efficiency.

Sure thats why you wont see tubes in this applications. It would be completly stupid. So still no need to talk about the efficience of 5w tube amps.You wont see tubes in BT inears.

 

[Brian Hall]

Sure thats why you wont see tubes in this applications. It would be completly stupid. So still no need to talk about the efficience of 5w tube amps.You wont see tubes in BT inears.

Now you've done it. I'm sure someone will try it.

 

[wwenze]

Speaking of battery-powered, I wonder how they pack 6 hours into each earbud

(21 hour total, 6 hour earbud 15 hour case)

 

[Brian Hall]

Speaking of battery-powered, I wonder how they pack 6 hours into each earbud

(21 hour total, 6 hour earbud 15 hour case)

I can get close to 8 with Galaxy Buds 2 pro if noise canceling is turned off. Maybe 4 with ANC turned on.

 

[wwenze]

Well it is about time for me to adopt ANC. Got a plane flight coming up soon too.

USD$100 for a working product from big corpo? Why can't landlords do the same with rent. And I thought mom and pop are supposed to be our friends.

I shamefully admit, my idea of prices have been stuck with Apple and Bose since I forgot other brands have started achieving good sound at lower prices.

 

[Svend P]

Class A operation has superior sonics to the other

So in your 8 years as a member here, you haven't read or learned anything? Maybe start with this thread.

So, are Class A power amplifiers actually any good?

As per the title, despite their inefficient design, heat output, cost and weight, class A power amplifiers are often upheld as a kind of 'gold standard' on many forums with out objective justification. I note that very few, (I can't recall one), have been tested on this very illustrious site...

www.audiosciencereview.com

 

[A.wayne]

Ok , sensing Irony .....

My position and comment on this stands , you should investigate it for yourself ..


Regards

 

[Jim Taylor]

Ok , sensing Irony .....

My position and comment on this stands , you should investigate it for yourself ..


Regards

Is it your position that you could take a double-blind test under proper controls and pick out the Class A amp to a statistically significant percentage?

Jim

 

[Petrushka]

Is it your position that you could take a double-blind test under proper controls and pick out the Class A amp to a statistically significant percentage?

Jim

Careful. You can pick out some tube amps.

 

[Palladium]

Is it your position that you could take a double-blind test under proper controls and pick out the Class A amp to a statistically significant percentage?

Jim

If there's any magic that eludes measurement then Bob Carver wouldn't have beaten Stereophile by plain old nulling and distortion knobs.

 

[Brian Hall]

Class A operation has superior sonics to the others, for headphones they make the best choice , class D is not for sonics but for high power @ reduced cost, size , etc ..

My DAP (Hiby R6 gen 3) has an option for class A or AB. The only difference I can detect between the two is that class A gets the DAP too hot to carry in a pocket and runs the battery down very fast. No audible benefit at all.

The class A option is useless.