Higher-End Class A/B vs. Class A Integrateds


I’ve been thinking about downsizing from separates to an integrated amp. I’ve noticed that some companies have both class A and class A/B amps that are both pretty expensive such as Luxman for example. Hegel seems to be well received and they’re not true class A as far as I know.

I was kind of under the impression that class A was better than class A/B due to lower distortion yet again, there are some well reviewed class A/B amps that are as pricey as some class A amps.

To be clear, it’s really not the price I’m concerned about. It’s the fact that some integrated amps $5000 and up are still only Class AB.

How do these higher priced class AB amps sound in comparison to true class A amps?

nicktheknife

@ronboco 

I could be wrong but I think the Krell K300i is made in the US.  Their lowest model is made in China I believe.

@curiousjim 

Hegel still intrigues me. They're not off my list anyway.  Especially if they will be available for a good price. 😁

@nicktheknife 

From what I saw the KAV 300i was made here and the 300 I is made in China. I’m sure it is still outstanding but I am leery about China stuff still. Happy listening! 

@erik_squires 

What's give you the idea that I wasn't refuting your comments regarding Class A crossover distortion?   I even supplied a reference to the Wikipedia page. I don't see any reference information backing your comments.  And how did you come up with Pass Laboratories distortion specs?  I checked their spec sheet and it lists no distortion specs whatsoever, and neither does their user manual (I checked the XA30.8's). 

So, I sat down with Bing's ChatGPT-4 system and asked it.  This is what it provided, including references, for the question "What's the differences in distortion between a class A audio amplifier and a class AB audio amplifier?";

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A class A audio amplifier is a type of amplifier that operates with all of its output devices conducting through the full cycle of the input waveform¹. A class AB audio amplifier is a type of amplifier that operates with its output devices conducting for slightly more than half of the input waveform².

 

Some of the main differences between a class A and a class AB audio amplifier are:

 

  • Efficiency: Class A amplifiers are less efficient than class AB amplifiers, as they waste more power as heat and require more quiescent current¹². Class AB amplifiers are more efficient than class A amplifiers, as they reduce the power consumption and heat dissipation of the output devices².
  • Distortion: Class A amplifiers have lower distortion than class AB amplifiers, as they avoid the crossover distortion that occurs when the output devices switch on and off¹³. Class AB amplifiers have higher distortion than class A amplifiers, as they introduce some crossover distortion at the zero-crossing point of the input waveform²³.
  • Sound quality: Class A amplifiers are considered to have better sound quality than class AB amplifiers, as they produce more even harmonics and less hum¹⁴. Class AB amplifiers are considered to have worse sound quality than class A amplifiers, as they produce more odd harmonics and more noise²⁴.
  • Power output: Class A amplifiers have lower power output than class AB amplifiers, as they are limited by the maximum current that can flow through the output devices¹⁴. Class AB amplifiers have higher power output than class A amplifiers, as they can deliver more current to the load by using pairs of output devices in push-pull configuration²⁴.

 

Source: Conversation with Bing, 11/13/2023

(1) Class A vs AB - Audio Science Review (ASR) Forum. https://www.audiosciencereview.com/forum/index.php?threads/class-a-vs-ab-do-they-really-sound-different.18415/.

(2) What are the Different Types of Audio Amplifier Classes?. https://www.audioholics.com/audio-amplifier/amplifier-classes.

(3) Class AB vs Class D vs Class A Amplifiers (The Truth). https://boomspeaker.com/class-d-amplifier-vs-class-ab/.

(4) The Difference Between Class A and Class AB Tube Amps. https://www.middle8reviews.com/difference-between-class-a-class-ab-tube-amps/.

(5) Class A vs. Class AB guitar amps - Sweetwater. https://www.sweetwater.com/insync/class-vs-class-ab-guitar-amps/.

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And your references?

Please don't impart incorrect information to our members in the future.