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

@curiousjim 

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

Pass is now sounding intriguing as well.  

@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.

@pcolvin🤣🤣🤣🤣🤣🤣🤣

God you are hilarious.

@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.

@nicktheknife check out Norma ipa 140 integrated at Audio Thesis in Arlington.

@nicktheknife

Well, as far as class A amps having a certain sound IDK. As far as class A/B amps having a certain sound IDK?

But my own personal exposure leads me to think "different amps sound different" regardless of their class. This sadly won’t take you to quick and easy answer.

I presently have two pairs of "similar" but different monoblock amps both putting out similar numbers 450w@8o and 850w@4o, and 600w@8o and 1200w@4o. Parasound JC1+ and Luxman M-10x. These amps sound nothing alike. One 25w Class A, the other 12w Class A, but yet very different sound signature. Both great amps, and yes I do prefer the M-10x, but still they look the same on paper, yet are very different in sound.

Secondly I have two "similar" but different Intergarated amps both again putting out either 30w@8o Class A, 120w@8o AB, 200w@4o AB, or 150w@4o and 300w@8o AB. Riviera Labs Levante and Technics SU-R1000. These amps sound again nothing alike yet both have exquisite charm and character.

The type of amplification is secondary to the amplifiers design, I believe this to be very true and based on my own personal exposure I see and hear this every day.

Matching amps to speakers is yet another layer of detail to apply, and shades the character of both your amp and speaker.

I personally love the SU-R1000 for all that it offers and feel it’s an incredible amp in the 5-8k range, especially for vinyl. I feel it’s phono capabilities are on par with what I hear from my Mola Mola Tambaqui whilst listening to digital sources, even with a reasonably affordable MC cartridge ($500-1,000 range).

The Levante is intoxicatingly seduction and has power output options in spades, has a phenomenal headphone amp, and tube rolling potential to boot. 14-20k price range.

I also really love the Cambridge Audio Edge A from all that I’ve heard 3-6k, but enjoyed the Cambridge Azur line 851a which was one forth the price.

I haven’t heard, but have always been interested in the Michi line products as far as Intergarated amps go.

All would most certainly pair well with your Sonus Faber speakers.

Just to be clear, I think class wars for amps are silly.  The OP and other readers should buy what they like the sound of without much concern for the amplifier "class" except perhaps for heat and weight issues which buyers should also consider as part of the total cost of ownership.

The idea that a class is "best" isn't what my ears tell me.  There are some megabuck class-A amplifiers I can't stand, and some Class D amps I'd buy over them every time.

Class D, like Class A, suffers from legendary social memory about the technical differences which is often wrong or outdated. 

Far better, IMHO, to compare Luxman's Class A integrated to the Luxman A/B units. Listen for yourself with your speakers to decide.  The specs are (except for power consumption) kind of irrelevant.

Has anyone here heard the SoulNote integrateds, A2, A3?  They sounded nice at CAF.

I have the Luxman 595 Class A amp. I also have Yamaha AS-3200 Class A/B with the Yamaha rn-2000a as pre amp. 

The sound traits (to me):

1) Luxman 595 - Has a powerful meaty sound. Sounds a bit stuffy. Not very holographic. Sounds excellent for Jazz and also colombian music, though. 

2) Yamaha set up - sounds open, not stuffy. Good at being holographic.  I like the sound stage more than the Luxman. Sometimes can be a little to strong in the highs. It's bass is diff. from the Luxman. More tight/refined but less full compared to the luxman. The luxman bass can make the Bookshelves sound like towers. But I still like the Yamaha's bass a lot. 

Overall, I listen to the Yamaha setup 90% of the time. I use the Luxman for just jazz and Colombian music for the remaining 10%. 

I feel like the heat generated on idle is close to the same between the Luxman and the Yamaha as-3200. With the Luxman being maybe a tad bit hotter but not much. 

As others have said, try the different topologies and settle on what suits you. It’s really the only path to satisfaction. I happen to consistently prefer class A, but I would never say it’s categorically better. 

I just put my Black Ice Audio 3502P tube amp in with EL34 tubes.  After listening with the McCormack DNA 0.5 solid state amp all summer, it sounded warmer but sluggish(?) especially with rock music.  Small Jazz ensembles, acoustic music and vocals sound fine.  

I'm going to try the Gold Lion KT88's in to see if they make much of a difference.  

I'm trying to determine if I need a higher powered integrated than most Class A amps provide.

@dman777 - A lot of what you describe is what I hear with my 507ux.  I wonder how much of the character of our integrateds is in the preamp and not the amp section instead?

Also, speaking of bass extension, I highly recommend the Mogami quad speaker cables with the Luxmans.

@erik_squires for the Yamahas, the 2000 greatly influences the as 3200. With the AS-3200 by itself I do not like it. It has to be with the 2000. They go really good together. 

I have not messed with any preamps for the Luxman. I figure for the price, if it's not good enough standalone then I don't want it. I am on the fence on selling my Luxman 595. I will eventually buy the MacIntosh 12000. I might sell it down the road if I find I do not use the Luxman enough. It's hard to give it up... it does sound better than other amps for Jazz music. 

@dman777  Sorry, I was not at all clear.  I meant, when listening to say a Luxman 509 or 590 or 507, I wonder how much of the tonal character is actually the preamp section, as opposed to the A or A/B output stages?

Audition Pass Labs. Call Mark at Reno Hi Fi. Largest Pass dealer in the USA and maybe the world and a wonderful person, easy to work with.. Has numerous new and used products. Ck website for items in stock. You can audition and return . If return, you are responsible for ship costs only.

I skipped to the end. My amps drive my conventional{not horn} speakers to +90 db with less than 5 watts peak so get yourself an amp that runs in class a for the first 5 watts or so and above that we're just screamin and dancin' like a pack of drunk indians anyhow right?

@bubinga, Reno HiFi is now permanently closed.  Mark has retired.  

My ex Gryphon Diablo 300 class A/B was outperformed by my present Vitus SIA-025 Mk2 class A and lately my Vitus was also outperformed by a Jadis DA88S KT120 tube class A integrated.

The Jadis is about the same price as the Diablo 300.

This is my experience in the past 2 years.

The only reason there are still class AB amplifiers is practical: anything above 50watts pure class A (and that's already A LOT to ask) becomes huge, extremely heavy, extremely hot, probably unreliable, and uses way too much electricity. There's just no way around it. Otherwise all amps would be class A.

My Outlaw RR2160MKll class A/B is 110 watts per channel, Yeah it's Heavy, thats what I like about it, well one of the many reasons. Does not get Hot, get's warm after cranking it listening to Led Zeppelin for a few hours on my Turntable.

In the last 3 years I have gone through too many class A and A/B amps (integrated and separates) to mention. I just bought a Luxman L-509Z. I use an Aurender A20 as my digital source. Speakers are Harbeth SHL5s 30th anniversary. Even the phonostage is outstanding, IMHO. You will need a cartridge to match the specs of the 509Z. My Ortofon Cadenza Blue works very well.

I am no longer searching for an amplifier.

Update:

I ended up buying a demo unit Kinki Studio EX-M1+ from a small dealer in Michigan.

I’m beginning to feel I made a mistake. I know it’s Chinese but that’s not the reason for my feeling.

The unit was purported to have less than 20 hrs. on it and and I estimate that I may have put an additional 40 hrs. (?). The manual states 300 hrs. for burn-in. I’m not exactly sure how the sound is going to change but as it stands now, I have to say it sounds a bit underwhelming and disappointing.

This version does not have a gain switch. According to the manual the volume adjusted by steps up to 100. To get any decent volume for my relatively small room of 13’L x 12’W x 8’H and sitting approx. 6’ from the speakers I have to put the volume at least 60. Usually even higher.

The Kinki integrated is rated at 215 W rms (8 ohms) 290 W rms (4 ohms) both channel driven. Damping factor of 2000.

My speakers are Sonus Faber Lumina III’s rated at 89db sensitivity and 4 ohm nominal impedance.

To experiment I swapped the Sonus Faber for an old pair of ACI Sapphire III’s that are rated at 90db and 6 ohm, nominal impedance: 4.7 ohms.

Other than sounding different, the ACI’s were basically behaving the same way with the Kinki.

Before, I was using a McCormack DNA- 0.5 power amp with either a Classe Audio CP-50 preamp or Rogue Audio Model 99 Magnum pre. I didn’t have to move the volume up as much to get much volume or excitement out of either of these speakers and the McCormack is rated at 125W rms.

Could it be that the Kinki needs the full burn-in time or is that it sounds so smooth and laid back compared to what I went from that I am not getting very excited while listening? It is dead silent compared to the other combos and I’m picking up some subtle details that I wasn’t aware of before, unless that’s just because I’m listening more intently/critically since the amp is new to me.?

I’d appreciate any words of advice. I know one poster here owned the Kinki, albeit an older version I think. I recall him speaking of a gain switch which as I mentioned before, this version does not have.

Thanks,

Nick

Nick, you’re not alone. I also fell victim to the hype and bought a Kinki EX-M1+ (used). Nothing special at all. I would say below average. I sold it at a considerable loss within 60 days.
 

Sorry for being the bearer of bad news. 

The Kinki integrated is rated at 215 W rms (8 ohms) 290 W rms (4 ohms) both channel driven. 

The answer is in the quoted specs, unfortunately this amp is fairly gutless. Look for an amp that doubles the wattage going from 8 to 4 ohms, or at least comes close. 

Seems to me the rating for the Kinki at 8ohms was highly overstated and the relative low increase in rating at 4ohms indicates that amp is not suited for for a 4ohm speaker.  

Sad to say live and learn. Some really nice Simaudio gear on USAM and TMR right now, trade that kinki and be done. 

It seems the KInki may be better suited to a speaker with higher efficiency and more like an 8 ohm load.

The reviews I’ve read, all very positive btw never mentioned it having a problem driving certain speakers. In retrospect, perhaps I should have paid more attention to the speakers they were using in their review.

That said, I wouldn’t mind owning a pair of speakers that are easy to drive with almost any amplifier. It would give me more options.

In this class, if you have a chance, I would strongly suggest you check out Ayre.  I'm a fan boy and have landed there after trying lots and lots of gear over the years. Also, made in the USA and great customer support. Quality and reliability also top class.

Kinki Studio EX-M!+ owner here. I think the amp is great. I primarily use it with Buchardt S400 MKII speakers which are 4 ohms and the amps has no trouble driving them with authority. I also use them with my Triangle Comete EZ with great results.

On the volume front I'm usually between 60-75 when listening to vinyl which will have the music in the 75-85 DB range. When listening to digital I'm at 55-65 on the volume dial for 75-85 DB range.

I can push the amp and speakers to uncomfortable listening levels without distortion.

I have the Class A Luxman -595ase and I love it it. Paired with my ZU Omen Defs, the amp will run you out of the room with loud, super clear volume. I’ve never heard a home amp so clear at loud volumes..

One good thing about most higher quality integrateds is you can also add a different flavor power amp (tube, etc) thru the extra outputs while using the pre section of the integrated.

A while back, I passed up a great deal on a pair of Quicksilver horn mono tube amps. I was going to hook them thru the second outputs of the Luxman. I would just have to move the speaker cables from one amp to the other (or buy a high quality switcher).