My Long List of Amplifiers and My Personal Review of Each!


So I have been in a long journey looking to find the best amplifiers for my martin logan montis. As you know, the match between an amplifier and speakers has to be a good "marriage" and needs to be blend exquisitely. Right now, I think I might have found the best sounding amplifier for martin logan. I have gone through approximately 34-36 amplifiers in the past 12 months. Some of these are:

Bryston ST, SST, SST2 series
NAD M25
PARASOUND HALO
PARASOUND CLASSIC
KRELL TAS
KRELL KAV 500
KRELL CHORUS
ROTEL RMB 1095
CLASSE CT 5300
CLASSE CA 2200
CLASSE CA 5200
MCINTOSH MC 205
CARY AUDIO CINEMA 7
OUTLAW AUDIO 755
LEXICON RX7
PASS LABS XA 30.8
BUTLER AUDIO 5150
ATI SIGNATURE SERIES 6005

With all that said, the amplifiers I mentioned above are the ones that in my opinion are worth mentioning. To make a long story short, there is NO 5 CHANNEL POWER AMP that sounds as good as a 3ch and 2ch amplifier combination. i have done both experiments and the truth is that YOU DO lose details and more channel separation,etc when you select a 5 channel power amplifier of any manufacturer.
My recollection of what each amp sounded like is as follows:

ATI SIGNATURE SERIES 6005 (great power and amazing soundstage. Very low noise floor, BUT this amplifiers NEEDS TO BE cranked up in order to fully enjoy it. If you like listening at low volume levels or somewhat moderate, you are wasting your time here. This amp won’t sound any different than many other brands out there at this volume. The bass is great, good highs although they are a bit bright for my taste)

NAD M25 (very smooth, powerful, but somewhat thin sounding as far as bass goes)
Bryston sst2(detailed, good soundstage, good power, but can be a little forward with certain speakers which could make them ear fatiguing at loud volumes)

Krell (fast sounding, nice bass attack, nice highs, but some detail does get lost with certain speakers)

rotel (good amp for the money, but too bright in my opinion)

cary audio (good sound overall, very musical, but it didn’t have enough oomph)

parasound halo (good detail, great bass, but it still holds back some background detail that i can hear in others)

lexicon (very laid back and smooth. huge power, but if you like more detail or crisper highs, this amp will disappoint you)

McIntosh mc205 (probably the worst multichannel amp given its price point. it was too thin sounding, had detail but lacked bass.

butler audio (good amplifier. very warm and smooth sweet sounding. i think for the money, this is a better amp than the parasound a51)

pass labs (very VERY musical with excellent bass control. You can listen to this for hours and hours without getting ear fatigue. however, it DOES NOT do well in home theater applications if all you have is a 2 channel set up for movies. The midrange gets somewhat "muddy" or very weak sounding that you find yourself trying to turn it up.

classe audio (best amplifier for multi channel applications. i simply COULDNT FIND a better multi channel amplifier PERIOD. IT has amazing smoothness, amazing power and good bass control although i would say krell has much better bass control)

Update: The reviews above were done in January 2015. Below is my newest update as of October 2016:



PS AUDIO BHK 300 MONOBLOCKS: Amazing amps. Tons of detail and really amazing midrange. the bass is amazing too, but the one thing i will say is that those of you with speakers efficiency of 87db and below you will not have all the "loudness" that you may want from time to time. These amps go into protection mode when using a speaker such as the Salon, but only at very loud levels. Maybe 97db and above. If you don’t listen to extreme crazy levels, these amps will please you in every way.

Plinius Odeon 7 channel amp: This is THE BEST multichannel amp i have ever owned. Far , but FAR SUPERIOR to any other multichannel amp i have owned. In my opinion it destroyed all of the multichannel amps i mentioned above and below. The Odeon is an amp that is in a different tier group and it is in a league of its own. Amazing bass, treble and it made my center channel sound more articulate than ever before. The voices where never scrambled with the action scenes. It just separated everything very nicely.

Theta Dreadnaught D: Good detailed amp. Looks very elegant, has a pleasant sound, but i found it a tad too bright for my taste. I thought it was also somewhat "thin" sounding lacking body to the music. could be that it is because it is class d?

Krell Duo 300: Good amp. Nice and detailed with enough power to handle most speakers out there. I found that it does have a very nice "3d" sound through my electrostatics. Nothing to fault here on this amp.
Mark Levinson 532H: Great 2 channel amp. Lots of detail, amazing midrange which is what Mark Levinson is known for. It sounds very holographic and will please those of you looking for more detail and a better midrange. As far as bass, it is there, but it is not going to give you the slam of a pass labs 350.5 or JC1s for example. It is great for those that appreciate classical music, instrumental, etc, but not those of you who love tons of deep bass.

 It is articulate sounding too
Krell 7200: Plenty of detail and enough power for most people. i found that my rear speakers contained more information after installed this amp. One thing that i hated is that you must use xlr cables with this amp or else you lose most of its sound performance when using RCA’s.

Krell 402e: Great amp. Very powerful and will handle any speaker you wish. Power is incredible and with great detail. That said, i didn’t get all the bass that most reviewers mentioned. I thought it was "ok" in regards to bass. It was there, but it didn’t slam me to my listening chair.

Bryston 4B3: Good amp with a complete sound. I think this amp is more laid back than the SST2 version. I think those of you who found the SST2 version of this amp a little too forward with your speakers will definitely benefit from this amp’s warmth. Bryston has gone towards the "warm" side in my opinion with their new SST3 series. As always, they are built like tanks. I wouldn’t call this amp tube-like, but rather closer to what the classe audio delta 2 series sound like which is on the warm side of things.

Parasound JC1s: Good powerful amps. Amazing low end punch (far superior bass than the 402e). This amp is the amp that i consider complete from top to bottom in regards to sound. Nothing is lacking other than perhaps a nicer chassis. Parasound needs to rework their external appearance when they introduce new amps. This amp would sell much more if it had a revised external appearance because the sound is a great bang for the money. It made my 800 Nautilus scream and slam. Again, amazing low end punch.

Simaudio W7: Good detailed amp. This amp reminds me a lot of the Mark Levinson 532h. Great detail and very articulate. I think this amp will go well with bookshelves that are ported in order to compensate for what it lacks when it comes to the bass. That doesn’t mean it has no bass, but when it is no Parasound JC1 either.
Pass labs 350.5: Wow, where do i begin? maybe my first time around with the xa30.8 wasn’t as special as it was with this monster 350.5. It is just SPECTACULAR sounding with my electrostatics. The bass was THE BEST BASS i have ever heard from ANY amp period. The only amp that comes close would be the jC1s. It made me check my settings to make sure the bass was not boosted and kept making my jaw drop each time i heard it. It totally destroyed the krell 402e in every regard. The krell sounded too "flat" when compared to this amp. This amp had amazing mirange with great detail up top. In my opinion, this amp is the best bang for the money. i loved this amp so much that i ended up buying the amp that follows below.

Pass labs 250.8: What can i say here. This is THE BEST STEREO AMP i have ever heard. This amp destroys all the amps i have listed above today to include the pass labs 350.5. It is a refined 350.5 amp. It has more 3d sound which is something the 350.5 lacked. It has a level of detail that i really have never experienced before and the bass was amazing as well. I really thought it was the most complete power amplifier i have ever heard HANDS DOWN. To me, this is a benchmark of an amplifier. This is the amp that others should be judged by. NOTHING is lacking and right now it is the #1 amplifier that i have ever owned.

My current amps are Mcintosh MC601s: i decided to give these 601s a try and they don’t disappoint. They have great detail, HUGE soundstage, MASSIVE power and great midrange/highs. The bass is great, but it is no pass labs 250.8 or 350.5. As far as looks, these are the best looking amps i have ever owned. No contest there. i gotta be honest with you all, i never bought mcintosh monos before because i wasn’t really "wowed" by the mc452, but it could have been also because at that time i was using a processor as a preamp which i no longer do. Today, i own the Mcintosh C1100 2 chassis tube preamp which sounds unbelievable. All the amps i just described above have been amps that i auditioned with the C1100 as a preamp. The MC601s sound great without a doubt, but i will say that if you are looking for THE BEST sound for the money, these would not be it. However, Mcintosh remains UNMATCHED when it comes to looks and also resale value. Every other amp above depreciates much faster than Mcintosh.

That said, my future purchase (when i can find a steal of a deal) will be the Pass labs 350.8. I am tempted to make a preliminary statement which is that i feel this amp could be THE BEST stereo amp under 30k dollars. Again, i will be able to say more and confirm once i own it. I hope this update can help you all in your buying decisions!


128x128jays_audio_lab

speedbump6,

You know more about Tektons than I, and I am interested in your listening evaluations, comparing Moab to Ulf.  I imagine the Ulf with all Be tweeters to be killer, but above 300 Hz, the Moab with all Be tweeters would be equivalent at $14K.  The Ulf below 300 Hz would probably be superior, since the upper bass is handled by the smaller faster driver in accordance with the designer's concepts.

@whitecamaross,

Just piping in here a bit to express my gratitude.

Years of following this thread paid off. I grabbed a pair of Audiomica Consquence ICs and SCs and am gobsmacked at how they have changed my system. It was like upgrading a speaker or an amp. Never knew my speakers could produce such taut, ballsy, grippy bass.

My system: Bricasti M12 -> Nagra 300p -> Devore O/96.

BTW I am still waiting upon you to discover Nagra or Bricasti amps and DAC. Fingers crossed for their comparisons to your current favorites.
Nagra HD series (DAC, preamp, amp) or Bricasti M28 or M21 DACs are quite SOTA.

Cheers!
Heading home...long day and filmed a ton. Stay tuned for a great video tonight. Grab your beer or drink of choice. 
@essrand I've been a big fan of Audiomica cables now for awhile but if you've only experienced the ic and sc wait till you try their ac cords. They have made me forget about upgrading equipment and just enjoy the music.
Viber, actually I can’t say that I know the Tekton’s well yet. I’ve heard some, but as far as my own, not yet. My warehouse is looking more like an audio store than my regular business, lol. I’m waiting until I have everything together then I’ll work on setting up multiple systems in the house.  I’m at five systems currently to set up. Just got notified that my artesania rack will arrive to the dealer from Spain on Tuesday and then ship to me after that. Still waiting on the Tekton moabs for the rears in my home theater, plus other assorted pieces. I hope jays new setup dosnt blow me mind too badly, so that I have to make changes before I’ve even heard what I have now, lol
This has totally gone beyond my wildest dreams. I am out of words right now with this amplifier. Incredible isn’t even a word that does it justice. The sheer force, rumble, chairs vibrate, and other amps now seem to sound like receivers...not kidding...
Let me get off my cloud and I'll be able to put down my thoughts better. I am on cloud 9 right now 
@whitecamaross 
WC /Jay
Congrats on the Mephisto. Its a powerhouse and a monster of an amp.
its 0.5 ohms stable with 6000w . omg.
looking forward to hear your thoughts, upcoming videos and the chronicles.
speedbump6,
Look forward to all your Tekton setups.  It is a fascinating line.  The Electron SE gives one an opportunity to utilize all Be tweeters in the smaller array comparable to Double Impact.  The smallest, most nimble 5" mid bass drivers are used, so from about 70 Hz to HF you have the most focused nimble speed of the entire line, all for a mere $6500/pr. Dual 8" drivers are for bass.  Dynamics are probably still good, although those who want higher power dynamics with bass extension would choose the Double Impact with standard tweeters for $3K, or people with WC's taste would choose the top Ulf with the double array of Be tweeters for $19-20K to get the ultimate in everything in dynamic speakers.  Has anyone compared even the Ulf with standard tweeters at $10-12K with any top Wilson?
I’ll be able to once I get mine setup. I will have multiple systems. Wilson Sasha daws, and bw 800d3s, among a few others including an open baffle setup. Jay, you went to bed a little earlier than I expected, lol. I can only imagine what you’re hearing. Sounds like I may have to look in that direction myself at some point. 
Some need to come back to their senses about the new Gryphon amp. Sometimes there seems to be only cheerleaders here...

First, new amp and speakers at the same time in that room, so impossible to say if the new big rumbling shaking sound is not more the result of the Alexia 2 than the amp...

Second, a power amp power rating and capacitance is NEVER a reflection of sound quality. Mostly everytime, minimalist low power SET amps will have more purity. Simpler more direct signal paths is one of many reasons why less is always better.


Lol, I have zero doubts about what jay has said about the mephisto. Remember we already heard them with different amps, and with all the different products he’s heard, I’m sure he has a really good feel for what is giving him what he’s hearing. Yes, those alexias certainly have more bass then then what he’s had previously, no doubt. It’s not the cheering section. The mephisto is really that good.
No we didn’t heard them. It was the Alexia 1 not the 2. Different speakers , different amp. We cannot come to the conclusion that this Gryphon amp is better, sorry that doesn’t work that way in this hobby.
We heard some amps on his previous video playing on the current Alexia he has now. Therefore he has an idea of what they sound like with other amps, and is comparing the mephisto to that, and anything b else he had had or heard
You don’t have to assume if you don’t think it’s the case. I just know what I know, for me. In the end, I’m the only one I can speak for. 
Not to be too offensive but you really have a bad list of choices of amplifiers.  Where did you get this awful list of choices from?  If you have a hifi buddy or friends that have recommended these amps to you, you need to find better hifi friends.  I’m not referring that you enter into a higher price range, it’s that I’ve been in this hobby for 30 yrs and me and with my friends would not even bother with 85%-90% of the amps you have on your list.  
@lowtubes
If that comment is meant for me, then great. I am glad you have buddies you can do this with. I am a one man operation and I am quite happy with how much I’ve learned without reading some of the garbage that is published often times.
Lowtubes, 
The guy is a power rating junkie, so he tries everything with crazy specs.

I'm going to make a statement here BEFORE I START TO TALK ABOUT THE MEPHISTO in the future:
A mephisto is a F22 Raptor that takes off and quickly hits 1500 mph. It doesn't give a $hit about you being nauseous, or if your blood pressure drops or if you can not handle the acceleration or if you pass out because you don't have enough oxygen in your brain. This amp is about brutal delivery, quickness, and pushing the boundaries with massive effortless power. 
If you are the kind that would much rather fly in a private jet, sitting on recliners, drinking champagne while you eat sweet grapes then stay away from the mephisto. You need to stick to tubes and leave this amp for us big boys. 
Jay - big congrats on the latest acquisition and may you enjoy it for many months and possibly years to come.  Thanks for all the hard work, posts, advice and videos.  I hope you can sit back and enjoy your new speakers and amp while sipping your favorite adult beverage and immerse yourself in the musical experience!  You deserve it!
@lowtubes,
you are comments seem to be distasteful.anyways you are entitled to your opinion and taste and choices.why don't you list out your great discoveries and the list of amps which culminated from you and your great hifi buddies.
From my own perspective your latest video sounds great but not my cup of tea. Others in the past sounded more natural and real. Hard for me to really put in words but this setup is just too powerful for my taste. Yes this is what you are after and that's what it's about and I'm thrilled for you and your journey but I like something I can relax to but then be startled when the music demands. 
Again your hard work as always is most appreciated. 
Be safe!
@techno__dude
nobody is being a cheerleader here and most of them share their thoughts honestly and frankly.
neither did anybody say that great specs always result in great sound.
but bad specs and bad engineering never result in good sound for sure.
may be you can be happy with the distortion of many tubes and the subjectivity of your perception and hearing but not everyone is like that.
one thing is for sure that it takes phenomenal engineering to make an amp monostable and beyond that at half ohm.its not everybody's cup of tea to event attempt at designing and manufacturing such amps.
so its always a combination of good specs, good engineering and final parameter which is hearing and trusting our own ears.
A couple of things:
1. The video was recorded at around 88db. Louder than usual - this way you can get a sense of the power, delivery, immediacy and sheer force. 

2. You are also listening to an Alexia 2 which are more powerful sounding than DAW 
3. Alexia isn't broken in yet. 
4. Mephisto needs to go on a stand which will be the same I used on the momentum. 
5. This amp sounds waaaaay different than almost every amp I've owned. Don't expect the same sound because it doesn't sound the same. 
6. You can't make a .50 caliber machine gun sound off the same way as a 9mm does. 

I am having the most fun ever with the Mephisto. It pisses me off one second and then it blows me away. 
It doesn't sound like the Colosseum either (more to come on this)


It’s evident on this end. Obviously we never got to hear the coliseum with these speakers, but it’s more than that. As good as the coliseum was, it was never that sure footed. Where the coliseum have a sound that you can hear it’s strengths , but felt like you could reach your hand into it, like smoke, this amp feels like a wall of sound, if you could touch the sound, it would be solid, and a foot thick. It did not have the same control at every level, maybe better at some levels than others. The mephisto seems to have that control at all levels. And that’s just what I can hear from YouTube. I’m sure there more of the story there in the room with it. Holographic comparisons. Can you define where each instrument is in the soundstage better? Those and more are the things not really possible to hear online. 
Colosseum builds you a pretty house made out of wood or drywall.... Mephisto builds it out of brick and cement...
Colosseum is  Robin and Mephisto Is Batman. 

Check out the Rockport Technologies website...they have used the Gryphons for years to drive their speakers...
Fyi:
You might want to hear the last video again that I posted earlier today. As an FYI, YouTube takes time to completely process the audio and video after a video is uploaded. Typically the sound and video is better hours after it has been uploaded (when it's high def of course)....
Jay,

What is your comment on the new Essence Power Amp.  U have audition it. A Good buy?
Sorry , you cannot say the Mephisto is Batman and the Colosseum is Robin alone . The Alexia 2 comes into play big time.
I have to correct you, Mephisto + Alexia 2 is Batman. Don’t try to fool us ( we are not all cheerleaders).

Your way of changing gear, many pieces at the same time, always plays against your reviews... making them just a lot less serious. Your conclusions have to be taken with a huge grain of salt when you do so...and we keep telling you...and you keep doing so. Maybe you’re stubborn ( which I do not think), or it just happen you are like the monthly magazine reviewers you despise...PUMPING NEW GEAR WITH TRICKS...And lately snobingly so...
WC - Not sure if you still have the Cardas speaker cables that had some issues with your previous Gryphon, but it would be interesting to see how the Mephisto handles them. Enjoy the tunes!
Techno, jay isn’t a paid reviewer, he’s never claimed to use scientific methods, and not necessarily trying to prove or show each individual component to the degree you’re looking for. Reviewers do sometimes change components, ie soeakers in their systems, and still continue to make comparisons to products they’ve heard in the past on their past setup. Jay has made it clear he’s giving his opinions, not trying to make scientifically proven statements. With the numbers of products he’s had, I believe he is able to give a pretty fair assessment of what he is hearing despite the differences in speakers. All paid reviewers must do this also over time, as they update their systems as time goes by, and they’re having to use memory to make those comparisons with. Jay has stated he does this for fun, his enjoyment, and for those that like what he does, for their enjoyment also. The only way to do what you’ve stated would be to have all the products he has ever tested on hand all the time and then test them all on the same speakers. I don’t know any reviewer anywhere that does that. It would be cool to be able to do that and keep everything, just not realistic. 
Techno,
I believe you are starting to put a rope around your neck again.

First, WHY are you even thinking I’m fooling YOU specifically when this level of gear is leaps and bounds ahead of the McIntosh pre, Dynaudio speakers and luxman 900u you own ?
Would a Ferrari salesman try to "fool" a Volkswagen buyer when he knows he won’t be buying a Ferrari ? Why would he waste energy doing so ?

Secondly, as I’ve said it many times, you actually think I got a line of people outside waiting to buy the mephisto or Alexia or pass labs xs300? How is that sale working out for the distributor who’s selling the coliseum on here ? Wow it’s still there even at 40% off of MSRP?
That’s because buyers for this kind of gear don’t come around everyday.

Thirdly, you actually think I gain ANYTHING from expressing my comments about the mephisto? What would that be ? Because MOST who read my thread have explicitly told me they can’t afford it so then WHY would I spend MORE money into gear that is THAT MUCH HARDER TO SELL? why not just stick to simaudio, parasound, McIntosh etc and pump those up in here so I can sell more ? Do you see what I’m saying ?
Lastly, wdf do you mean by snobbily?
You want me to just play the equipment and cover it with blankets or stick in a closet so that nobody can see it while it is playing music ? Part of the damn REASON anyone buys a Momentum, mephisto, or an expensive speaker is to DISPLAY in his room.

WCSS, my only suggestion is on amp compares that you use stock cords. it really complicates things not to do so. i realize you are a bit of a cable junky, but that would be more apples to apples. 

congrats on the Wilson/Gryphon combo - will be curious how it runs in a few weeks.

one cool thing to try for your second system would be a higher efficiency speaker so you can demo low powered, simple amps. even amps like Dart (which unfortunately isn't good on low impedance speakers like the Alexia). Maybe Fyne is a good way to do that, Devore Xs another option. that would add more value to your channel to cover both ends of the amp spectrum.

 
WC, congratulations on your recent Mephisto acquisition! I’ve heard from several very experienced audiophiles, that Mephisto is not just one of the best, but probably is THE BEST stereo SS amplifier manufactured today. I have a choice between Antileon EVO and Mephisto. The difference in price in my case is around 12K Euro. I think I’ll go for Mephisto:) What would you do if you were in my shoes?
Can't talk about the Evo. I heard it's killer. I almost bought it myself but the stars aligned for a mephisto. 
Only thing I warn you about, it wont forgive you with crappy components or recordings. I suspect the antileon is more forgiving. 
Well, EVO is certainly not forgiving too. I’ve heard it in my system with my components both with vinyl and digital. If I wanted a forgiving amp, I would go with CH:)
Then you just corrected me about what I thought about Evo. Thank you for that. 
I almost bought it... I was one day away from paying for the antileon evo and then the call came in for the mephisto and well the rest is history. 
I have recorded several videos of the essence Amplifier driving different speakers. Stay tuned for that. 
@abedirov  I've heard both Antileon Evo and Mephisto stereo as i'm also in the market for this gear.I found Evo a little too warm and darker than the Mephisto, but the bass is phenomenal.Mephisto is much faster, transparant, very dynamic and still pretty organic.I think i'm gonna be pairing CH L1+X1 with a Mephisto stereo and not the Pandora pre.IMO CH pre with Mephisto is a perfect balance.
@thieliste
Momentum HD preamp and mephisto seem to have excellent synergy. However, I heard from someone who owns the relentless Monos and he is using the Pandora gryphon with his monos and he owns the HD preamp as well...go figure ?
I personally would love to bring the Pandora preamp home and compare against my HD Preamp...
One thing I can say is that I don’t like the Rossini directly into the mephisto...the soundstage is diminished and the 3d of the high frequencies is also absent. This phenomenon is now easier than ever before to be able to detect changes. I mean I knew going dac direct into amps in the past meant more detail but less control when comparing to a preamp in the mix. With the mephisto, you are now able to not only tell that story but you can also pin point what went backwards by removing a preamp (a great preamp of course) from the chain. 
So, how does the Audio Research Preamp sound on the Mephisto compared to the HD? Yes, I know, the AR is not fully broken in.

When are you going to A/B the Merrill with the Gryphon and also rate the Merrill?

And when are you going to get some serious fuses for the Gryphon and AR and HD preamps?  Good ones are only $20 each.  Way better sound with $20 fuses!  Takes you two minutes to change one.  The Parasound has a fuse for AC on the back panel and 6 fuses inside (OMG).....so changing all these will bring it to another way, way, way better level.  
I plan on trying the ref6se soon with the mephisto BUT I have to be honest about something: Mephisto with a tube preamp - for some reason - makes me feel like it's a step backwards. Here is why: you pay big money for the mephisto's ability to dig up more resolution than your average amp. It is an x-ray machine in many ways so using a tube preamp with it means you now lose the nuances, the minute details and information retrieval that you are paying for with the mephisto but that a tube preamp doesn't really do ? Think about it...you take 3 steps forward in terms of detail and resolution by going with mephisto and then you're going to take 2 steps back by going with a tube preamp and lose all that extra Information? Kinda doesn't make sense in my head...
So, if tubes are so lossy......why did you buy the AR?.....just to sweeten class D? A simple cable swap can do that......and a heck of a lot less money than a Seventeen thousand dollar "lose the nuances, the minute details and information" device.

If you really want more information.....then upgrade your fuses and ALL your stands. The fuses are practically free!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

And get those cables off the floor!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I want to see your face smile to the horizon when you change the fuses....when you get better stands and raise the cables off the floor.  I want you to be happy.....jumping for joy.
The arc ref6se was/is for the magnepan....and to try to see how the Merrill 118s behave with tubes in the mix since there were a lot of people who whined constantly about class d sounding dry or cold or sterile. I wanted for people to see how good a class d amp and a tube preamp can be.
Hell, I already said it here I had a dealer come over and listen to the Merrill with arc ref6se versus the full Momentum with my Alexia 2 and he chose the Merrill 118s with arc ref6se. The Merrill 118s with the arc REF6SE is incredible. I am very shocked at how good that combo is.
Think about it, you get the speed of the Merrill class d, tbe sweetness/romance  of the tubes and the bass control of class d. What's not to like ? 

On a side note, there is NO WAY there is only a 15 watt per channel difference in power between the coliseum and mephisto....HELL NO.... 
@whitecamaross  Yes i'm sure the HD preamp is a great match for the Mephisto no doubt about that.However i'm not so sure about the Pandora since there are other very good alternatives today like CH L1+X1 or even the new CH L10 and why not Audionet Stern.Been exchanging several times with a guy that owns CH L1mono + Mephisto Solos and Rockport Lyra and he told me it is the best combo he's had to date even though he still owns Robert Koda K-15EX pre.IMO Pandora has a lot of competition today and i'd rather put my money in a CH L1 which is much more future proof.Cheers.

@thieliste you may be right about the CH preamp. I agree: it is a more modern and more technically advanced design compare to Pandora, and you have better upgrade path: one L1 per channel plus 2 power supplies. If I have to go blind, I would choose L1 over Pandora. Another very interesting option in my view - MSB Reference DAC with preamp module. I auditioned it last week and it was a revelation going with MSB direct into Aesthetix Atlas Eclipse. The preamp is fully analog, it’s a passive unit with constant impedance. Think about it: the dac with modules is about $50k. And you need about $30k to get a sota preamp like CH or Pandora. 
WC,
The ARC ref 6se is not a typical tubey type preamp.  In your video with the ARC and 20.7, I didn't hear any tubey quality.  The Dag HD preamp might be more tubey than the ARC.  Years ago you said the ref 6 was more focused and defined than the ref 10.  Try the ref 6 and Merrill Christine preamps with the Mephisto.