Which amp matches best my JM Lab Mezzo Utopia ?

I have clearly a predisposition to single ended and Class A design. Push pull does not apply. The speakers are a demanding load though. They go down to 3.8 ohms.
The BAT solid state amps deliver lots of current, so that handles your load requirement, and are biased heavily into Class A. As such, they run hot, but I've owned BAT pre/power for the last seven years with no desire to make a change. Don't know them with the Utopias, but my Magneplanars are 4 ohms nominal, and there's never an issue of drive or control.
buy the best amp you can find like the cary 805 or air tight 211 and see if they work with your speakers. If not, get rid of your speakers, they are broken. the amp is king.
A friend of mine uses a LA audio 300B amp (mono amps 8 watt), it's a very fine combination. 3.8 Ohm isn't that low, if i remeber right they have a efficiency of 92 db, i think this is more important.
The 211s are really an option for me. My concern is that they have only 22w of power. Wouldn't it be better to go for solid state Pass Labs XA 160 - class A 160 watts more so as I use a passive pre?
Sorry, but the XA160 is not single-ended.
I have thought it is parallel single ended very much like the Aleph.
The way I understand it (I guess I have to say I am an electrical engineer), is that the Aleph is truly single-ended but the XA series is, as Pass puts it, "parallel single-ended" which to me is just marketing jargon to fool audiophools into thinking they have a single-ended output stage when in fact, the input is single-ended but differential. Parallel balanced output is not single-ended output. You have to read his website more carefully or just believe it and get an XA160 and be happy!

I read somewhere that it's not recommended to use SET amps with speakers that have impedance below 8 ohms.
If using a balanced amp on the unbalanced input : do both halves of the amp operate or not? If only one half of the balanced circuit and no intention to use a balanced source then buying a balanced amp is a loss of money. Anybody?
Sensitivity of the Mezzo is stated to be 92.5 dB. It is measured up to 2.8v. In 4 ohms this is not watt/meter. 2.8 v makes it watt/meter in 8 ohms. The sensitivity of the Mezzo up to watt/meter is somewhere 3dB less - 89.5 dB as the reviewers have measured it and stated it does not correspond to specs but without explaining the reason.
thats not vey demanding load i would get something soft in the top end for the jm labs
I am using Jadis JP200MC AND JA500 4 ohms. I think this is the best matching in my Mezzo Utopia system especially the mid range and bass is perfect. I don't think low watt or single end can control the bass. If you prefer low watt a smaller room may be accaptable.
Blanket statement: you'll need ~50W class A or ~150W hi-bias class AB to get the Mezzo singing with appropriate dynamics. (They may be nice speakers but they consume lots of energy.)
So, given current pricing on quality hi-power tubes, I would recommend a SS.

Pass makes nice amps, but to use passive volume control you'll have to match their input impedance which is quite low if I remember correctly (check it out). OTOH, a low input impedance picks up less noise (mine is 10-12k Ohm across the board).
Thank you All!
Gregm, thank you - I have decided to go for a tube amplifier but will follow your advice to look for a 45-50 watt amplifier (may not be a pure class A amplifier though)!
When I purchased mine back in 2000, I listened them with a pair of Lamm parallel single-ended amps, some Thor monos, a Simaudio solid-state amp, and my own amp of the time, a McIntosh MC500. I definately preferred both the Sim and the Mac compared to the other two, mainly because of the bass response.

Since then, I've set up these speakers in five different living spaces, and the bass is the aspect of the Mezzos' performance that I'm least happy with . . . they can either get really boomy, or turn around (with position changes, or even different recordings) and sound thin.

The vintage Marantz amps I'm running now are by far the best I've ever heard with these speakers. They're P-P EL34 amps, and unlike most SE designs, maintain a pretty low output impedance. (Amps with higher output impedances are usually associated with the traditional "tubey" sound: relaxed highs, boomier bass).

And one thing I will say is that I have never once wished for my Mezzos to have boomier bass, in any room. Thus, I personally wouldn't be looking at single-ended amps as a good match for them. But as always, your mileage may differ . . .
Aleko, if you use a balanced amplifier with the single-ended inputs, the entire amplifier gets used.

Your speakers are tube-friendly but they need more power than most SETs offer, and the issue that you face with SETs is that the more power they have, the less bandwidth they will be capable of. You will definitely hear that on the JM Labs!

There are tube amps out there that have a lot in common with SETs (class A, zero loop feedback, all-triode) that will make the power that you need, and do it in a very classy way.
Atmasphere, I guess that you actually are the Atmasphere company?
Had read somewhere though that it is not efficient to use a balanced amplifier with an unbalanced source (as mine).
I am not targeting a balanced amplifier for this reason
as it is naturally more expensive due to the doubled circuitry.
Why pay for double circuitry and not concentrate the funds on a better quality single type circuitry.
A matter of strategy I suppose.
On the other hand I know that a balanced amplifier will provide more current at output which will be good for a hungry speaker like the Mezzo.
Aleko, wherever you read that tidbit, its not actually true. Also FWIW if the amplifier is balanced-differential you do not have 'doubled circuitry'. Differential circuits have the advantage of lower noise and lower distortion as opposed to their single-ended counterparts. This can be a big deal depending on the complexity of the amplifier. In single-ended circuits the distortion of one stage is compounded by the distortion of the following stage. Obviously a fully differential amplifier will be lower distortion.

Lower distortion is usually audible in 2 ways: more transparent (detailed) and more relaxed (regardless of bandwidth).

The Mezzo is a tube-friendly speaker, but does need some power to make it go. You will be a lot better off with 50-100 watts than you will be with 7-15 as a result. The speaker will literally wake up!
Hi Aleko,

I am not familiar with too many brands & amps.
I am using Dual Mono Block Tube Pre-Amp and Mon0-Block
Tube Power Amp ( P-P 300B ) and had them driving my
Mezzo Utopia for almost one year. Tube-rolling, ( of course only changing the 6SN7, 5U4 etc. not the WE 300B )
inter-connects/ power cables changing were all failure
to make it sound to satisfaction. So don't use Utopia
with 300B amps. (other tubes may be suitable more )

Because I like WE 300B so much, finally I had to change
to Parsifal from Utopia.
I remember wonderful combination of Mezzo with JRDG Concentra + MBL DAC + Helios Stargate as a cd drive. Don't remember name of the cables.
Has anyone tried the Mezzo with a single ended amp based on the 211 tube ?
Or with a parallel single ended amp based on 2 output tubes like the 211 or the 845 ?
Or the GM 70 tube ?
Any shared experience is welcome.

As a current SET owner my Audio Valve Challenger Class A tube mono amps sound much better than any SET I have owned and I have owned over 30 SET amplifiers. SET are just a wee bit better in the midrange and its slight but everywhere else the AV stomp on my SETs.
What amplifier have you compared to AV Challenger?
Do you use also Jm Lab speakers?
I would like to ask you this :
Which amplifier would you prefer
- Air Tight ATM 211 or
- Wyetech Topaz A Mono

for use with the Mezzo and why ?

The Topaz M has great reviews , AT also.
I have auditioned the Air Tight 211.
It is awesome.
It has Tamura transformers .
These simply sing.
One thing only is that it has noise (audiable).
I have not auditioned the Wyetech Topaz.
The Topaz M is obviously more powerful and seems to have
more robust power supply.
Because of this my preference has gone to the Topaz so far.
One thing which makes me feel uncertain still is that the Air Tight is transformer coupled while the Topaz is capacitor coupled .
The capacitor introduces phase shift as fas as I am aware.
Will I get the direct immediate sound with the Topaz the same as or better than the AT 211 ?
Any suggestion is welcome.
I would suggest that you need at least 100W with a transformer that can drive the bass woofer. I have a pair of JM Lab Alto Utopia and tried a few tube amps. Then I found that a hybrid amp is the best for these speakers.

I am happy with my Counterpoint NP100 platinum: 100W at 8ohm and 200W at 4ohm.
Aleko, I would like to respectfully suggest that you're definately over-thinking this whole thing about selecting an amplifier . . . and this is coming from somebody that very much likes to understand and think about the technical aspects of audio.

But the pile of opinions and discussions above, spanning almost three years . . . this is WAY more information than you'll ever need. Probably time to simply listen, think less, and don't second-guess your ears.
Vet93, from your experience I understand : 100W minimum.
Others have said it too .
The power of the amplifier appears to be the limitation factor in these speakers' case.

Kirkus, you are absolutely right.
Enough is enough !
Aleko, what amps have you tried on your Mezzo Utopias? Let me know what you think of them.....
Vet93, here it goes :

- Pass Aleph 3 - solid state single ended 30W.
The small 3 sounded fine with the Mezzo .
I would say it did the same as with 8 ohm speakers .
It used to get quite hot during operation.
There was the see through soundstage existing.
Output current is limited with the 3 though.
Subjectively this created the impression that the amplifier is trying too hard.
- Primare 928 monos - solid state, push-pull 100W.
At 100W a better match, maybe a very good match.
Good soundstage and bass line.
IMO these are very good amplifiers.
Easier operation but some clarity lost compared to the Aleph 3 .
- Gamut D200, solid state, push-pull 200W.
Good match especially that you can adjust the gain by the 4 switches inside.
Especially valuable for me as I use a tube phono pre-amplifier with cathode follower output and no line stage but only passive - selector and ladder volume attenuator.
Powerful sound, bass line was very robust, the speakers got in control .
The soundstage was very wide but not quite deep and see through like.
The highs were probably not that clear as with the Aleph but the mids were very good and the bass was much deeper .
The solid state character was still evident though.
The effect for me is that I get easily tired and want to try something else .
That is why I have started the discussion saying that I am going for a SET tube amplifier.
From what I understand it seems that the Marantz 2 you are using is a very good match for the Mezzo.
Sorry for mistaking your system with somebody else's I have seen ...
hi, you just have to try the XA.5 amps from pass labs, pure class A and way more power than the aleph 3. you will get the see through soundstage , but with better dynamics and more controlled bass. a good mach would be the XA60.5 monoblocks, 120 watts into 4 ohms. I dont know of a better sounding solid state amp !!! goodluck, chrissain
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I ended up with Belles MB200 mono amplifiers. Solid state differential circuit. 200 watts in 8 ohms 400 watts in 4 ohms and the Mezzos have 4 ohm impedance. A very good match and I use it without pre-amp only selector ahe Goldpoint ladders. The Belles MB200 have 100 kohms input impedance.