What class of amplifier has the most high definition sound ?

@ vt4c
+1 Focusing on bias class is a waste of time. Find a good pairing with your speaker is more important. Difficult speakers will reduce the choice of amplifiers. 

(Except for this last sentence ... ¨ Shun those 85dB speakers.¨ in which I also believed until after years of owning a pair of passive ATC20s, decided to hook them up to a Mastersound parallel SET 20w/channel integrated and was pretty surprised. Speakers are 8 ohm nominal though and the Mastersound has some pretty hefty transformers.)

But getting back to OP,  comment by  georgehifi ...¨ Best, least coloured, fastest, cleanest, most dynamic a Class-A OTL tube amp, trouble is the speakers they love to drive are the "polar opposite" if full range 20hz-20khz.¨ ...seems to hold true with the  high efficiency speakers I´ve heard. For whatever reason lower efficient speakers have always appeared less colored.

Still miss my Celestion 600s (Stereophile measured them at 81db/1w/1mt. back in the day I believe), even with their lack of bass, but most definitely not my pair of Klipsch La Scalas which they replaced.

+1 @douglas_schroeder -- but the fact remains, when all other pieces of the audio system are dialed in and set, the amp choice still matters. As with everything in audio, the chain is only as strong as its weakest link. And you can carry that down to the design of the amp itself. No matter what class of amp, all the other design parameters and choices affect the final outcome. So while I might prefer the strengths of a Class A amp in general, I’ll take a well-designed Class AB amp over a poorly-executed Class A amp hands down.

I have heard many SOA contenders & with a compatible pair of speakers nothing has ever matched the purity of an OTL.  I remember the first time I heard a Futterman.  It was certainly dirty sounding (enough to disqualify it in many ways),  Even so it had a purity in the upper midrange in particular, that was unequaled by any objective or subjective standard. End of story. By any amplifies.   A high quality OTL wiil far surpass it.  I don not own an OTL.  The speakers required are not anything I've encountered so far.  Nevertheless it is & no class of amplifier I've heard comes up to that standard. None.  Although there are some pretty wonderful ones for other kinds of systems that overall may be better compromises.

soix, I concur; we are not in disagreement. We may vary on what we feel the degree of contribution the amp (whatever type) and the system contribute, but both are critical to desired outcome, and everyone will have their favorite genre of amp. Absolutely, the quality of the amp in the chain is critical! And, people will feel strongly about the genre of amp they think is superior. 

A. Nothing is better, except maybe single ended class A.

Give Spectral a try. There are a number of reasons you may find it rewarding. Resolution combined with macro and micro dynamics. Utterly uncoloured. They are fanatics; and Professor Johnson has never been influenced by money or short term gain. It’s a very unusual company; a pure pillar of truly high end audio. 

Hi there
We can get the most natural sound from class A amplifiers. They have "soft" distortion spectrum and they are stable for pulse signals because of stable power consumption. But they produce some specific problems too. Open my page in LinkedIn (Vladimir Benkhan). There are couple articles about it and a description for simple class A amplifier.

The amps that shine in class A are the pre-amps .

You can listen to an amp that that tested off the charts in the lab, has the greatest reviews, in your setting sounds sub par. I think end of the day, it’s the pairing, room, setting, and the hearing and how one process the sound and the music. I’ve had $$$ amps and tried low wattage boutique amps that sounded better, to MY ears. I’ve had arguments with friends that tell me I’m foolish for spending what I did on gear, and say their blu tooth speaker sounds great.  End of the day, there are more factors to the equation.

OTL -  Atma Sphere

Would like to know where the Devailet amps score in this? (Class A in parallel with Class D).For those familiar with them please chime in.

I have a new definition.  With research (listening research) and a budget that matches your research, it is the amp you bought given the rest of your equipment.

Lots of excellent input here, especially M Green, and George

IME, the interaction with the room plays a very significant roll

I am blessed and cursed with a large room (~ 19 X 35 X 12 i. The blessing is virtually no boundary interference. The curse- finding a amp/speaker combination that will properly energize the room without going overboard

I just replaced a excellent Audio Alchemy 175w/ class D stereo amp with PS Audio M700 monos which only have ~ 200 hours on them (bought them slightly used). Even stone cold, they did a better job of energizing the room (I could better hear deep background low level tinkly things, like in the opening of Famous Blue Raincoat Joanne of Arc, BUT, I think I really need to double their ~ 350/700w to get the full texture

Speakers are Emerald Physics KCIIs @  92dB with Clarity cap and Wire World upgrades +. even though a very benign load, I am told the KCIIs love some power. To compensate, I have  2 SVS Bash amp subs (Ultra and Plus), but their volume control is way too coarse at lowest volume they come on too much, so very hard to blend  

IN MY ROOM I probably need Ice EDGE power @  ~ 1200w to properly energize the room

1. OTL
2. Really good switching amps ONLY with linear power supplies. SMP’s will foul up the entire presentation.
3. Superior A/B solid state amplifiers

What a can of worms.  Synergy is the real quest.  It's mating the loudspeaker to a power amplifier that has the right chemistry.  Certain combinations or one particular amplifier are/is pure magic while others are simply pitiful. 

Just so we are clear- there are classes of amplificationandthere are types of amplifiers.

The class of operation has mostly to do with how the output devices in the amp are turned on and how long they are on. In this regard both solid state and tube amps can be class A, class AB, class B or D (yes, you can build a tube amp that is class D). Class C is not used for audio- its typically used for radio frequency transmitters.


A *type* of amplifier has to do with its topology (circuit design) and often what sort of devices it uses in the output section. For example an SET is a type of amp using entirely single-ended circuitry and a triode for a power tube. An OTL is a tube amp that does not use an output transformer. There are single-ended solid state amps (ala First Watt amps from Nelson Pass) and most solid state amps are output transformerless, so the OTL moniker is usually reserved for tube amps. These days all class D amps are solid state, but they can have half-bridge and full bridge configurations.

I have to go with class  A....