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

@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?";

========

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/.

===========

And your references?

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

 

 

 

@erik_squires Was your response AI-generated too?  Ehem.  I think in general if you’re relying on ChatGPT to make your arguments here your credibility sinks like a stone and likely for good reason.  Might go over well on Reddit tho. 

@soix

 

Yes, I am nothing but an amalgam of Internet myths without the ability to independently validate the veracity of anything. 

@soix 

My response was not AI generated. For reference I used my own knowledge, and refreshed it using items such as Tremaine's Audio Cyclopedia, Wikipedia, and ChatGPT because their all decent research tools.  Other than referencing them (properly) to provide further backup, everything was written by me. 

As for me, I’m an old analog electronics engineer since the 70’s who’s designed 6-track sound-on-film equipment, record cutting equipment, amps, crossovers, speakers and theatrical and roadshow sound systems.

I own a Pioneer M-22 class-A (which I can cook eggs on) and am presently rebuilding an HK Citation 11 pre.  In addition to these around my house I use a Revox A-77, a rebuilt Accuphase E-202, a dBX 1231 1/3-octave EQ, a Cambridge Audio DACMagic 200M, an Anthem Statement, an Arcam CD37, a Nakamichi cassette deck, and a JVC-QLY55F turntable with AT and Shure carts, a Sony STR-V35, a Denon AVR, and an assortment of Sonos devices.  I use REW for system setup.

Hope this answers your question.