Living room system: class A or AB amps?

Would class A be suitable for a living room system? Apart from hi-fi listening sessions, it's also used a lot for watching TV.

Would it make more sense to get good class AB amplifiers, which can be switched on permanently without drawing huge amounts of power? I wouldn't want to warm-up an amp first before getting good sound.

For this system, I have so far only purchased the speakers: Focal Stella Utopia Evo. Room is big: 1,200 square feet with openings to hallways.

I'd consider to pair them with Gryphon Mephisto and Pandora. But that's class A...

Opinions and amp suggestions are welcome!

Class A is suitable unless its a more formal living room in which case go with Class`e. Dining room systems are of course Class D and bathrooms don't rate a class but most people take the Schiit. Some say the point is sound not topology but these people have no class.
With your depth of experience and knowledge I was hoping for something more substantial. A class-y response that would actually help me :)

I wish I could ignore the practicality factor, but it’s a living room.

For class AB I'm thinking two Luxman M-900u's in mono.
You will still get good sound from a cold class A design, it will just sound even better once warmed.  That's true, to a lesser extent, with class A/B amps.  Some amp manufacturers tout how their amps run class A up to certain wattage before switching to class A/B operation.  One of those amps could be a good compromise for your situation.
Just get the amp that sounds the best with your speakers.  The only limiting factor would be if you needed to hide the amp in an enclosure.
Just get the amp that sounds the best with your speakers.  The only limiting factor would be if you needed to hide the amp in an enclosure.
You'd have no problems running class A amps at hundreds of watts day and night in the living room?

Unfortunately no dealers out there with Focal Stella Evo's on demo with several different amplifiers to audition.
Let alone my considerations: Gryphon Mephisto, Luxman M-900u mono, and D'Agostino Progression mono.

P.S. I may want to have some enclosure around the amps, but easy enough to add some active ventilation with quiet fans.
Robert, it sounds like you know your answer about Class A. Just get Class A/B or better Class D. I have a FirstWatt J2 Class A and it will get really warm. I had a prior class A/B and I could leave it on all the time without any major heat issues. I do not do this with my J2. I would look at Pass a/b's. 
PASS 250.8 or 350.8 asap!!
Would that be enough for the 374lbs a piece Focal Stella Evo’s? I’d rather risk a little overkill vs. underpowering them. Guess X600.8 monoblocks then?

Robert, it sounds like you know your answer about Class A.

Not so sure yet. Just read class A sounds good too without a warm-up (although better as temperature increases). I live in a tropical climate and my room temp is always at least 25°C / 77°F.
That may shorten warm-up times compared to a system in a Canadian basement in winter :)
robert1976 OP Would it make more sense to get good class AB amplifiers, which can be switched on permanently without drawing huge amounts of power? I wouldn’t want to warm-up an amp first before getting good sound.
Get an Gryphon Antillion, (switchable Class-A Bias) that way you can switch up the Class-A only when you listen.

Leave it on in low bias all day, then when your ready just switch it up, and remember when you listen to a Class-A amp up to a point the louder you listen the cooler they run.

Think of it as the water pressure behind a tap washer, the pressure (is the amp heat) the more you let the water flow (listen to music) the less pressure there is behind the tap washer, turn of the tap (music) and then the pressure (amp heat) is at it’s greatest.

This is why when you listened to the massive classic Mark Levinson ML2 monoblocks, they ran cool as a cucumber, stop listening and they got very hot, even though they were only 25w full power at 8ohm, but that 25w was all Class-A.

Cheers George

Vitus SM-103
You choose between Class A or Class B
                                    Rock or Classic
A lot of power
Aestheticly speaking : no blingbling , no meters , no firecrakers.
But it is expensive .

     As you know, you have very high quality speakers that deserve a high quality amp,or better yet, a pair of monoblock amps to drive them.  A pair of Gryphon class A monoblock amps controlled by a Pandora preamp are very likely to be a very good match for your speakers. 
     Each amp, however, consumes 700 watts to operate at idle and up to 2,650 watts during normal operation, which is roughly equivalent in electrical consumption of 1-4 high powered hair dryers.  Due to class A amp output transistors being run with constant bias, both of the large Gryphon monoblocks will very likely provide enough combined excess heat to significantly raise the temperature of your tropical climate room. 
      Given your requirements for very high quality amplification for very high quality speakers, that do not produce large quantities of excess heat and that can economically remain powered on in an optimum operational condition on a 24/7 basis,  I suggest you may want to at least audition a pair of very high quality Merrill Audio Element 118 class D monoblocks, in your room and system, before deciding to purchase any other amps.     
     Attached below are links to a professional review and followup article about these exceptional, unique and expensive amps:

Best wishes,
Class ?
That should determine little or nada.
Put some powered desktops on the TV and buy what amp favors the speakers most.
With your depth of experience and knowledge I was hoping for something more substantial. A class-y response that would actually help me :)

Sorry, but the idea of shopping amps by design class and room is so ripe for ridicule that WAS the classy response. Its one small step down from the ones who want a certain size to fit on a shelf or whatever. At least that has some merit. Or relevance in the physical world. The idea of Class A vs AB because: living room? Sorry. Does not merit anything but cracking wise.

We here at Chez Miller select amps based on sound quality, performance features, and budget. What class it operates in never enters the picture. Now if its a small room and one amp generates a lot of heat that’s a performance consideration that may rule out Class A- but may also rule out tubes. Either way its nothing to do with Class. We don’t care about that. Designers care about that. Not users.

Its just nuts for users to fantasize about this stuff as if they know the first thing about it anyway. We have a guy here knows all about it, and every time he posts nobody understands a word but they all fake out like they do. The whole charade goes on and on until it gets to where we have a thread like this, I want to put a system in my laundry room, what Class A or AB?? Is all tubes okay for my walk-in closet or is a hybrid phono stage better?

There comes a point, see, where the subject gets so goofball humor really is the classiest response.

On a seriously helpful note, and as always: forget what class the damn thing is. Focus on sound quality, performance features, and budget. In that order.

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Those speakers are tremendous.  A/B gear is going to run a lot cooler than class A.  I run low wattage tube amps and they run absurdly hot and warm my room.  Big, class A, SS amps are going to generate a ton of heat.

Not going to be as cool as Class D, but check out the AVM Ovation 8.3 mono's.  They will deliver plenty of power for any speaker and are extremely natural sounding. I have a pair that were damaged in shipping around if you want to hear them.  They are jaw droppingly good and I think will be an interesting alternative to Pass.  

Another interesting option would be VTL Siegfried IIs.  Again, tons of power and tonally VTL would be a good match. 

Gryphon and Pass are fine options and are certainly great sounding.  Good resale with both.  The other one I can't believe hasn't been mentioned is Naim.  It is the sister company and it sounds amazing. 


Maybe I should have chosen different words, and leave "class" out of the equation.

Little kids, pets and a living room environment may require a rack or cabinet. For these customers, size, weight, heat and safety become real factors. Nobody wants their toddler to fall face forward into a bed of sharp heat sinks. They may choose D'Agostino Momentum monoblocks over Pass Labs XS300. Because they both sound great but the Momentums run cooler and are easier to fit into a cabinet. Safer and more suitable in a living room.
You may cringe because these restrictions mean they will never hear the system's full potential. You may find it a waste of money. But why not if you have the budget to get awesome speakers and high-end components? Yes, the restrictions suck. But it beats defaulting to a $3,000 home cinema set. 

Best Class A: I do like the warmth and natural sound of Wavac, Ear Yoshino and Metronome Technologie.
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Have you looked at the McIntosh MC 1.2kW or the newer MC 1.25kW amps, they have plenty of power to drive those speakers. and they are built to last.

" Class ?
That should determine little or nada.
Put some powered desktops on the TV and buy what amp favors the speakers most."

Hello fuzztone,
     I agree, amp type is not relevant when selecting an amp based on sound quality, however, it definitely becomes very relevant when  selecting an amp based on additional amp qualities such as electrical efficiency, size, weight and a low operating temperature. 
     Who knows?  I guess it might even be technically possible that someone, somewhere, who lives in a tropical climate, has high quality speakers and may even be an active Audiogon member,  might even have the shear audacity to be searching for The Friggin Holy Grail of Amps, which has the highly unusual combination of amp qualities of having excellent sound quality, being highly electrically efficient ,being light in weight. small in size while also constantly operating at a safe and moderate operating temperature regardless of the speakers' reproduced frequency and its correspondingly difficult impedance level presented to the amp.
     I believe we both agree that the possibility of an individual actually searching for such a highly proficient audio amp would be, at least theoretically, a discrete possibility.  Based on your post comments of "Class ?  That should determine little or nada.", however, it's obvious you lack even a basic understanding of how and why class D amp type technology generally, and the class D technology contained within the Merrill Audio Element 118 monoblock amps specifically,  represent such a useful, important, relevant and elegant solution to robert1976's amp search.
     As to your other brief post comment: "Put some powered desktops on the TV and buy what amp favors the speakers most."
     To be fair, however, I must also admit that I also lack a basic understanding, or even a clue, about what the heck this statement even means.


True. The Pass Labs X600.8 stays in Class A up to 50W, which is quite high.
Oh, you should obviously use [insert MY personal favorite here] with your Focals.  After spending so much on your speakers (hopefully from a reputable dealer), are you trying to tell us you are more willing to listen to a bunch of opinionated schnucks over the recommendations of your dealer, who probably has a lot more experience with amp pairing with those particular speakers than any of us, or did you go grey market to "save money'?

Did you just call your fellow forum contributors "schmucks"?

In my country, not a single Focal dealer has the Stella Evo's on demo. At $140,000 MSRP, who does? Even if they had the Stella's, they don't have the amplification to match it. So I have to travel and hear components separately.

I'm here to get suggestions and ideas (not to "listen" to anyone). That way I found out about Gryphon and the Mephisto. Which I will be auditioning this Friday. Thanks for contributing nothing but negativity.

How high is the ceiling?
It's 10ft to the plaster ceiling, then another 1/2ft to the concrete slab.
I'm about 12 feet away from the speakers.

Regarding doubling down when impedances halves: I think both Pass Labs and Luxman M-900u do a good enough job at that.

If going for Pass, I'd veer towards the X600.8 monoblocks.

Luxman monos will give you superlative performance. Don't second guess it.
That's encouraging! Did you hear them personally? If so, with what speakers?
For watching TV? Okay....
Not just for watching TV. That's just a by-product because it's in the living room. I regularly enjoy long listening sessions, and that's why I'm spending this kind of money.

P.S. I got the newer Stella Evo's. You referred to the older version of this speaker, now on discount.
hey Robert,
I think you know the answer.... its a trade-off of heat, power cost, whether you feel green, and sound.
Lets begin with the fact that being class A vs AB is not the most important determinant of sound quality.  A high-bias AB design does 99% of what a class A design does, at a 75% power/heat/cost savings.  And a well designed AB will sound better. Only when all other factors are equal does the last 1% matter.  keep in mind also that "AB" covers a wide range of bias levels. Either you understand or i cant explain it succinctly here (but am happy to offline).
if you are talking tubes, its a bit clearer, but would one leave tubes on 24x7 anyway? I hope not.
Maybe I'm falling bait to a joke, but listen and evaluate against the practical impact of electricity and heat. I personally cant justify wasting that much power since my amps achieve the vast majority of their warm up in about 30 minutes.  But then again, it was a design goal.
To OP, If I had just spent 100K or 65K on sale for that matter. I would think it a no-brainer to jump on a plane and go to the highest of the high-end dealerships who sells Focal and audition amps in a large space. Obviously you're going to spend the dough it takes to get the rest of it correct, meaning to YOUR liking.  Good luck...let us know.
Turn on the AC and enjoy the music.  Those are quite nice speakers that justify good amplification at big cost.  Heat may be hard to avoid and Class D may not sound right.
I like the ARCAM AVR 850.  They have class G technology which provides pure class A for the first 50 watts.
I have Utopia Scala Evos and use mine similar to the way you will(music, TVs, and movies).   If you have the dollars I would go with Gryphon(you can adjust the bias) or Naim.   Both are great with Focals in my opinion.   Good luck!  
robert1976 OP

Robert I gave your answer to leaving it on all day with low heat and power consumption. Yet still having Class-A sound when listening.


I read your suggestion, thank you. The low bias button is like a "stand by" button. Before a listening session you simply press the high bias button. The Mephisto has that too.

robert1976 OP The low bias button is like a "stand by" button.
No, not stand-by because that means the amp is not on, but a low biased high wattage Class-A/B amp that you can just leave as a warm up or use for non serious listening, eg: parties, dinner parties, background music etc etc. No heat or big Class-A power bills.

Then if you want to listen seriously you just press the medium or high bias buttons, and there’s no wait time involved to listen to great Class-A sound.

Cheers George

FWIW, the Pass Labs x250.8 gets no hotter than a warm (not hot) cup of tea after running for hours. (You could keep your hand on the amp for a long time...not that you'd want to.)

No, not stand-by because that means the amp is not on
I understood that, hence "stand by" in quotation marks ;)
Thanks again.
In moving to a Class A amplifier, the main thing to consider is heat dissipation. If you have very efficient loudspeakers that will provide the level of sound you prefer in your living room, using a Class A amp should not be too much of an issue. You would most likely be able to get by with a relatively low power rated amplifier, either tube or solid state, and not worry about locating the amp inside a cabinet, for appearance purposes, provided the location has some reasonable ventilation as well as sufficient surrounding space inside the cabinet. I'm not sure what factor is prompting your question. 
Personally speaking, there are many fine sounding Class A/B or even Class D amps that may satisfy your audible enjoyment. I find that the majority of quality built Class A amps on the market tend to be a bit more pricey than A/B or D class amps. I'd take a serious look at the rest of your system. If the dollar investment doesn't exceed, say $10K, you may not reap enough sonic benefit to justify "CLASS A" expense, to say nothing of whatever appearance factor you may be trying to achieve.
robert1976: "Did you just call your fellow forum contributors "schmucks"?"

Hello robert1976,

     I believe he actually called his fellow Audiogon members "schnucks".

     According to The Official 2020 Audiogon Forum Discussion Rulebook, often informally referred to as "The Bible", it unequivocally states the following:

     "If an Audiogon member calls another official member a derisive name but misspells that derisive name, for example intending to call another member a "schmuck" but misspelling it on a post as "schnuck", then it is not only officially permitted by Audiogon for fellow members to refer to this mentally challenged member by numerous similarly derisive names without penalty for a period of 1 year, it is in fact highly encouraged.               Furthermore, if the offending misspelling member is a repeat offender, such as our especially dimwitted member bigdaddy2, then members shall feel free to strike down upon thee with great vengeance and furious anger those that attempt to poison and repeatedly misspell the English language.
     According to a recent statement from the author of The Official 2020 Audiogon Forum Discussion Rulebook, Samuel L. Jackson, "our rulebook committee has just unanimously decided that fatdaddy2's misspelling of 'schmuck' as 'schnuck' represents such a major mental malfunction and high degree of schmuckery, that, beginning with the 2021 edition of our Official Audiogon Forum Discussion Rulebook's Supplemental Dictionary, we will be placing a picture of fatdaddy2 as an example in the dictionary's entry for the word 'schmuck'. "

Thank you,
Clayton Audio Class-A amps fly under the radar but get stellar reviews and most models have a high/low-bias switch.  The S2000 would sufficiently power pretty much anything and costs $11,500.  Just another option to consider, and best of luck. 
Personally, I have my stereo on most of the day if not 24/7, so AB for me.

If you are looking into class A, consider the Lusman 590, which has much more power than it's spec.
Class A amps do sound good very quickly after fire up, and I prefer the ones I have, anyway, to many Class AB amps.

The downside is that the smaller versions of my amps put out 25 watts of sound and 300 watts of heat, and power consumption is accordingly high. (I believe mine put out 40 w and emit around 400 watts of heat)
Class A amps do sound good very quickly after fire up,
Because they (at least mine do) reach around 80% of their "A" bias straight away, the other 20% takes a bit longer once the heatsinks get warmed up.
This is why I always recommend "if you have the money", the Gryphon Antllion, as when switched to low bias everything is on, but it's only 5w bias, kind on your power bill, but warm enough so that when your ready to listen, you press 100w high bias and it gets there much quicker. Or you leave it at 5w for parties, background music, etc There is a 50w medium button, but I don't know what you'd use that for.

Cheers George