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

Showing 50 responses by jays_audio_lab

quick update:
i just unpacked the mc275s and connected them to the Renaissance and wow.... i think i can go ahead and say that the mc275s are something special.. After 1 hour of use, they sound so beautiful and full with nice midrange and highs. 
Emotiva is a good amplifier. i actually own 3 emotiva sa250 stereo amps and have used them with the mcintosh c1100 tube preamp and they do sound wonderful. Remember one thing though, if you are going cheap with the amps, YOU MUST go higher on the preampfification/ processor. I had the anthem avm60 connected to the odeon and it sounded spectacular. The bryson sp3 with the odeon did not impress me at all though so this is a prime example of system matching. The bryson sp3 is an amazing processor though, but it does not work well with the odeon just like plinius amps don't sound great with electrostatics (too harsh sounding). 
I love plinius and their products are outstanding, but you gotta be really careful with system matching. For now, i am here having a drink and listening to the Renaissance and a pair of mc275s and it is heaven to say the least. Incredible synergy and musicality and to my ears they sound better than the 601s do with electrostatics. 

@dlcockrum 

Not a bad idea to try what you suggested above but I don't have another room... 

One thing I wanted to add is that tubes don't really draw much attention on the channel... The topics that typically blow up are:

  1. Cables 
  2. Dacs
  3. Speakers 
  4. Amplifiers
  5. Turntable (seems to be so far)
Ouch.... Boulder 2160 call came in... Ugh... can't do it, too much dough tied in so many amps right now. Damn it I would love to have 2160 next to mephisto and let them go to war. 
interesting. i am running them in mono and i love them. i will say one bold statement which is that i prefer the mc275s over my mc601s for electrostatics. It just seems to sound like a perfect match. it is like wine and cheese. Incredible musicality and yes, 75 watts of tube power sound better to my ears than 600 watts of solid state when using electrostatics. Heck, i own 2 pairs of martin logan renaissance right now.. .
Zaks,
pass Labs is still a great amp for electrostatics. In my opinion, tubes are a better match but for 2 channel listening. If you are running a 2 channel and home theater simultaneously then pass is your best bet. Tubes are amazing for music but they don't have the dynamics for movies as solid state does. 
Dave,
I've always wanted to try the 28b model but they are just too pricey and the Bryston brand is whored a bit too much that one never knows when a good deal is really a good deal. I don't buy amps to keep forever. My joy is to keep trying stuff out and write down my findings. This is why I don't go for brands like ayre, certain Bryston models, dan agostino, etc. They just have such a crazy used market value that swings all over in terms of resale value. I'm not in the market to buy an amp and then once I'm done with it, ill have to lose 1,000 dollars or more to unload it. If I did that then I would be living under a bridge after owning 160 amplifiers in the last 2 years. 
Hey Ron,
the classe amps are great but you need to be careful with what speakers you use. I have found them to be somewhat warm sounding and if you have speakers like sonus faber then you'll be disappointed. They need bright or forward sounding speakers to really sound great. The pass Labs amps you mentioned are on another level than the c2200 you want. Pass simply smokes classe audio in my opinion. Classe has gone backwards with their amps rather than forward. I feel they haven't really revamped their amps and everyone has either caught up or surpassed them. It's a shame because their stuff is really well built. 
Hi,
i have zero experience with 350.8. I would say the 250.8 should suffice in most applications plus it's easier to live with than the 350.8. The 350.5 ran really warm and I would never attempt to put it in an enclosure. 
I love pass Labs and maybe that's why I'm planning on purchasing my next pass lab amp (200.8 monos). 
The issue with pass Labs is that it's a tough sale on the used market. I think it's Reno who's really hurting dealers across the board. Pass Labs is a great brand but it just doesn't hold it's value. It really depreciates as fast as an audi does. I still can't understand the used market. Nothing holds value better than McIntosh and b&w. It's like having apple products. 
Not really... anyone who buys it will lose 1,000 or more trying to unload it. Trust me that's not a good deal. Reno offered me one for less than that during Christmas. The 250.8 is the safest amp to invest on. It sells, its popular and not a lot of $. The expensive pass Labs don't move. They sit for years and don't move. Believe me, I've had dealers offer me their demos below cost just to get out of them. 
If you are a person who worries a lot about heat, pass Labs, old krell, plinius, old delta classe are all amps you should never ever consider. Those are heat guns. 
I have just purchased a pair of McIntosh mc2301s tube monoblocks. I currently have the mc601s and a pair of mc275s. I Believe I will be the first person to ever have all 3 amps at once so I will be sure to give you all a complete rundown of my listening impressions. It should be really interesting because pass Labs is stil at the top of my list but the mc275s seem more holographic than the pass Labs were. They don't have the low end oomph that the pass Labs has because it's tube amp but based on everything I've read and consulted with others, the mc2301 is the last amp to own. It's supposed to have the least floor noise than any other McIntosh amp which could make its presentation really amazing.  If the 2301 defeats the pass Labs I owned, I'll be sure to share that. That said, remember I use Martin Logan renaissance speakers so tube based amps will always have more voltage than solid state amps which carry more current. Electrostatics sound better with more voltage than with current which is why I seem to find the mc275s better sounding at normal to moderate levels than pass Labs. However, I also have a different source which I didn't have when I owned the pass Labs amps so I'm sure that's also impacting my listening impressions. 
2 of my buddies heard the mc2301s with some sonus faber 100k speakers and they said that it was Mind boggling what they heard. Just simply better than being at the live presentation. I'll be sure to report back to you all. 
Been a pass owner myself. That said, if you have doubts about my findings or my personal opinions then you can certainly skip over my thread and don't read it. I don't collect a dime from anyone for doing this. Nobody pays me a cent. I buy all this gear with my hard earned money and share my personal views so that audiophiles who don't have the means to buy as much gear as I do can actually read what I have to say and let them make their own decisions. If they doubt me then they don't have to follow my thread. There have been a few users here who share my views on a lot of the amps I've owned. I actually have recommended amps to some
of them based on their goals and they are extremely happy with what I recommended. Some of them even message me directly thanking me for my input because it gave them clarity about a certain amp they wanted to purchase. A perfect example would be to go on all forums and try to find someone who has the McIntosh mc275s, mc601s and mc2301s all at once and provide direct comparisons. Right now pass is king with electrostatics in my opinion but the 2301s are SUPPOSED to best anything out there that is tube based. Again, I can't confirm but I will in about 2 weeks. Please know that this hobby is subjective. Magazines are always hyping up products that pay them nice royalties for doing so. Take stereophile for example. They hyped the hell out of the salon 2s and I thought they were really poor performers. No bass and not exciting. Why would all magazines hype them up ? Well it's simple; Harman international  does tons of advertising on these magazines And talking  crap about their products would mean a loss of revenue in advertising. Makes sense? 
I was banned from the avs forum for a reason. I gave my true opinion on several threads and that didn't sit well with dealers who sell stuff through there including their own sales department. It impacts sales when someone with actual experience in the field makes bold statements about products but I don't care. Im very well connected in this industry and can snap my fingers and I get calls for good deals because dealers need money to pay bills and guess what? High end gear doesn't exactly fly off the shelf but bills keep piling up. This is how I have been able to remain on top of this hobby and in other aspects of my life. Remember, at the end of the day I'll tell it like it is. You wanna know why? Because  I don't have anything to lose. 

So in order to avoid any issues with a comment I made about women on my video , I have decided to take the video down. I have to keep in mind that although there is "freedom of speech " , it is really still frowned upon to say certain things. I don't feel like editing anything out so if you got to see the video then great. 

As far as luxman, I'm in talks and could potentially bring one 900u which could be the return of an amp I've owned before. Can't make promises but you never know. 
For those of you who love to assume , the constellation stuff is already packed up and ready to ship to its new owner before I even released this video. 
As far as Gryphon, we shall see what I end up deciding. For now, it's staying until .... 
Well, I let go of 5 items just now... Moving forward. Fridays video will reveal what has left. 
I’ll edit the video and upload later. I was being "unfiltered" so my apologies to you all. I thought it was only men watching !!! I deserve to take a punch for the team !
My apologies to all ladies!
Cheers
Techno's job is to be the antagonist. Don't worry, I'm putting a special touch on my next video... :) 
Over 150 amps owned in the last 3 years. From pass Labs, classe, krell, bryston, simaudio, ati signature, theta digital, nad, Cary audio, Plinius, and many more I can't remember right now. The McIntosh mc2301 tube amps have totally distanced themselves from the rest of the pack. They are in first place and everyone else fights to earn my second place vote. For right now, the mc2301s have unquestionably destroyed the rest of the amps that I've had the pleasure to listen to. They are more neutral than my mc275s and won't make a crappy recording sound amazing but they will make a good recording sound spectacular. 
McIntosh 2301s are without a doubt more engaging and holographic. I can hear the artist take a breath between each pause. The midrange is MASSIVE to the point that words that used to be mumbled in certain songs are now CLEAR and articulate. These amps put the artist in the middle of your living room. They are VASTLY superior to the mc601s I had to the point that they make the 601s sound anemic and compressed due to the fact that the 2301s throw a large soundstage. I began to dig up music from the 90s and 80s that I heard when I was a kid and I almost don't even recognize the songs because of how much detail that was uncovered by these amps 117db SN ratio. They are a mc275 but with a big turbocharger attached to it that makes them sound unreal. At this point, I am going to begin researching all preamplifiers from all manufacturers and hopefully find a superior preamp. I know these amps can give me more and although I am happy with them, I wonder if my preamp is a bottle neck. 
With all that said, I have my top 4 for electrostatics:
1. Mc2301s (#1 by a huge margin)
2. Mc275s 
3 pass Labs 250.8
4. Pass Labs 350.5
Hi,
unfortunately you won't get all those things when you are using a receiver as your preamp. Save your money and replace that thing with a better processor. I think the best processor out right now is the McIntosh mx160. Amazing machine but a big cost for sure. If you need something cheaper then look into a bryston sp3. Forget about buying amps when you have a weak source. 
Awesome to hear this. Most manufacturers hand us diamonds in the rough and we either polish them or not. The Merrill is a perfect example of what can be done and how far you can push. Clarity in spades , smooth, clean sounding and awesome speed with bottom end control. I've had some people who listened to it in my room and some preferred it over the momentum set up I have here. The mephisto will also go through the motions and partnering and I have a feeling it will be spectacular when I do what I have planned for it. 
McIntosh 207 doesn't touch the Odeon. Odeon is the best multi channel amp there is. Period 
The big update i have is that as many of you know, I find the weak link in my set up to be my preamp. I tried the c2500, classe cp800 and McIntosh mx122. So far, I feel I can get more out of the mc2301s. With that said, I have ordered the reference mark Levinson no52 preamplifier. This would be the most expensive component that I have ever owned at $30,000. Reviews are speaking as if this is the last preamp to own. I can't wait to hear this machine. 
Also, I will be taking a stab at the bel canto m600 monoblocks. These are class d amps and according to a good friend of money who owns far superior gear to what I own, he claims the bel canto will kill my mc2301s. I don't personally believe it but coming from his mouth is certainly enough to make me want to try them out. I don't personally like class d amps because I find them too fatiguing but I have not tried these and they are supposed to be amazing and smooth so here I go again. If these bel canto which retail at 6,000 per pair can take out the $24,000 mc2301s, this will be the biggest upset to my audiophile ears. I simply don't think this will be the case but if they do, I will have to completely redo my set up. 
Stay tuned, things are just about to start getting interesting. :)
Yes i owned it. Good amp but runs too hot and they tend to go back to krell to get recapped because overtime the capacitors begin to leak due to the heat. 


Just wait...i have already purchased 2 amps and preamps that will go toe to toe in about 3 months. 
Then hopefully by Christmas i can do the biggest amps ever... (My back hurts)
Thanks guys. I am also very curious to hear all these. The mark Levinson no52 has certainly grabbed all of my attention and I can't wait to hear what it can do with these 2301s. I may also have a chance to try the no536 Levinson monos
which are even more money than the 2301s. 
Yes. All was the same.
Ok so I am going to do a video comparing the following 3 PCs:

Audioquest dragon HC
Odin 1
Audiomica Consequence

Every single thing will remain the same. The only thing I will be changing is the PC on the gryphon. I will not disclose which powercord I am going to be using as I film each video because this way nobody is biased. I will cover the powercord being used and you all will decide if you like PC 1, 2 or 3. Then I will reveal which PC you all preferred. If you can’t tell a difference at all then this means I should keep the cheapest PC out of the 3 and sell the rest. I want you all to shock yourselves with your pick so maybe this will give you food for thought.

Once this is done, on a separate video I will do the following:

Odin 1 on dac plus Odin 1 on amp

Versus

Audioquest hurricane hc on dac plus audioquest dragon HC on amp .

I can’t do audiomica because I only own one audiomica PC which is for my amp.
Not enough power to make an accurate assessment. The 60.8 monos are far more powerful than this Nagra Amplifier. 

No boulder for me anytime soon. I think the gryphon will be my go to amp which will be switched out occasionally when I have something new to play with. 
The Gryphon Is extremely extremely picky with power. You can't use a 15a outlet on it or it will fall apart. I am using a 30a outlet and it sounds great there but I did try a 15a outlet and it wasn't impressive. 
Keep that in mind when purchasing gryphon. 
No I don’t have any aftermarket 20a in pairs. Only have the 3 mentioned above which cost a boat load of money as it is. i am Not going to be buying pairs of 20a PCs at this price point. Most of you out there don’t buy any of this level of PCs due to how expensive they are so doing shootouts of cables like this are just an added bonus from me to you all. i add them to my videos to give you something to hear and see for yourself, but i know 90% of you are not going to be heading out the door to buy Audioquest dragon HC PCs for your entire system.
Sometimes i buy something on the fly because i have an itch, but one thing i won’t do is to buy 2 pcs of this brand, then 2 of that brand, then 2 of the other brand and then 2 of the 20a versions of each brand, etc, etc.

Can’t embark on that journey unfortunately. i mean, could you imagine if i had 2 pcs of each of the top brands? i won't ever finish doing this... i would be spending weeks just changing out cables.. 
Also, i know someone above mentioned about reviewers living with components for months on end in order to give accurate assessments. yes, this makes perfect sense, BUT lets keep it real: would you all want me to sit on my a$$ with a component for 5 months and then give you my input? Most of you follow me because of my sickness and constant trials that never end. Some of you are as sick as i am in terms of audio, but perhaps don't have the funds to keep trying stuff out so you live vicariously through me ( i have been told this in person at shows and via pm's fyi). 
That said, i am very thankful to Audiomica though for allowing me to hear their stuff.
There's nothing on loan from any dealer. Everything you see on my last video is mine. The only thing I've had on loan lately was the audiomica cabling that's no longer with me. I did end up buying a 20a PC from audiomica. No free lunches in my room 99% of the time. 
Nordost Odin 2 on dac
Nordost Odin 1 SP
Cardas clear beyond xlr from dac to pre amps 
Odin 1 xlr from preamp to amp 
Stock pcs on all amps

I was being sarcastic......since when do I buy what people tell me to buy here ....
Hi,
yes, multiple amps are always better than one single amp but you need to have a good power plant like a furman or a ps audio p10 which I really believe is the best power plant available. 
The brightness that you refer to is because emotiva and anthem sound indeed like that together with your speakers. If you need to warm things up a little then use an anthem amp or classe. I don't like any anthem amplifier that is not their statement amps. Stick to their statement stuff. 
Lol @ Ron
The DAW was on my radar because I heard it twice at 2 different shows and liked it since axpona 2019. It is a good speaker but I’ve got mixed opinions so far. Can’t talk about it just yet. Don’t want to jump the gun. The only thing I’ll say is that the w20se is CRAZY AMAZING.
i am contemplating the GTA. It is on my radar, but i need to do my homework before. 

Anyhow, i wanted to say that those of you who found the constellation audio "muffled" or "smeared" should probably stay away from luxman as well. I disagree with what was said about constellation, but i do understand that not everyone likes the same so it is all fair. Remember, if you do not like Constellation, then you have zero business buying Luxman. You will not like it either. 
ok guys, sorry for the long Hiatus here. I have since my last update used and auditioned the following amps:


Belcanto Ref600 monoblocks
Simaudio 860A stereo amplifier

ok, so with that said, here is my update:

Belcanto Ref600 monoblocks: Amazing bass control and massive power. These amps really are the steal of the century and as good as my 2301 tube monoblocks were, i ended up parting ways with them after i heard these class d amplifiers. I did tons of a/b comparisons and i was extremely impressed with the amount of detail and smoothness that these class d amps have. I will go on record and say that these are the best class d amps i have ever heard and really made me question why we need to spend more money on other more pricy amplifiers. The highs were smooth, midrange was good and great bass. The music never fell apart when driven hard. It remained really composed without any strain of any kind. Nothing really bad to say here. It runs cool, weighs very little, can be put anywhere in your room. I will say that this is a sign of where we are headed in years to come. More efficient amps, more power, less heat and less weight. 
Great amp for the money!!


Simaudio 860A: This amp was a rare opportunity for me. However, i bought my renaissance speakers when i first them being pushed by a simaudio 860a with the 850p reference preamp (amazing synergy). 
when i first plugged in this amp it sounded a bit cold, sterile, lifeless, not much bass and punch. I was very disappointed to say the least, but i proceeded to leave it on for about 4 days and later came back to audition. It was now a different animal. It had gobbs of bass attack, and a level of detailed high frequency that i can only remember hearing from a class A power amplifier. I had approximately 5 days of play time and listened at low and high volume levels and i must say this amp possessed the finesse and punch that the bel canto did not have for me. It contained some of the silkiest highs i have ever heard with zero listening fatigue even after hours of listening. It never made me cringe or want to turn it down. I will say, this amp is perhaps the biggest competition to the pass labs 250.5 or 250.8 or even the  350.5. If you have speakers that need more detail and OOMPH on the low end, do not look any further than this amp. It runs extremely cool to the touch even after hours of listening and it is perhaps one of the most visually appealing amps i have ever owned. If pass labs amplifiers are too much heat for your current room, THIS IS your amp. It is really a reference power amplifier with the bass that i probably can't recall ever hearing. I would say in terms of bass punch, it is as punchy as a pass labs 350.5, but with a better midrange. The only thing the pass labs 350.5 has over it is the extra horsepower, but that is it. 
In my opinion, this is damn close to a pass labs power amp in terms of sound but without the crazy amount of heat. Highly recommended!
alright guys, i have updated above the last 2 amps and my impressions. I am currently auditioning my most expensive purchase and let me tell you, it isn't cheap, but my ears are just not believing what they are hearing. Stay tuned, i will come back and let you all know what amp this is....   The only thing i will say is that it weighs 250 lbs per mono! 
very interesting observation. I will have to try those some day. yes. i do believe class d will eventually be the future and at a much cheaper price point. That said, i know some of you are probably wondering what these monster amps i am playing with right now are... Well, they are a 2 chassis monoblock which makes the total weight of 250 lbs per mono. Monstrous sound which has everyone who has come to listen to them this past weekend leave my house with their jaws on the floor. It is by far the most complete sound i have ever heard in my room. 
OK guys, so i have decided to disclose the amps that i have been using for the past 2 days...  i was not looking for these amps, but i came up on a great deal and decided to give them a shot and let me say that yesterday i sat down at 3pm and listened to music until 3am this morning.. i couldn't get off the couch. It was just impossible to leave my room because of how amazing these amps sound. With that said, i am now the proud owner of pass labs XS150 mono blocks!! :) 
I am just on another planet now in terms of sound. It feels as if i got brand new ears and i am learning to enjoy every single cd, mp3, dsd file that i own. It is really an impressive amplifier and i don't see anything that can come close to its sound quality. 
Here are a few things i can already say:
1. Mouth-watering high frequencies. These are smooth, silky and with a level of detail and organic feeling that is almost impossible to believe. 

2. Midrange: very full bodied, not overblown, and it seems to be as big as the space between both front speakers. 

3. Bass: OMG! It pressurizes the room. It almost feels as if the woofers extend far enough to touch my listening chair. 

The separation is so big that you feel like you can walk in between the instruments. It is a really incredible and magical experience and it should be because these are $65,000 dollar mono blocks. That said, the improvement was MASSIVE in all regards. The only downfall would be that if you push these puppies hard then the temperature rises and they can get hot. It is important to have a room that is not tiny or else your lower legs will be sweating. You need to have enough ventilation in the room. That said, i am going to be selling the simaudio amp and bel canto ref600s in order to recuperate some of the money that i have invested into these Pass Labs XS150s. Let me know if anyone is interested :) 
thank you guys. i love these amps to say the least and they will be with me for as long as i can keep them. i want to just experiment with different speakers and preamps, etc. As a matter of fact, i used my sonus faber olympica 3s last night with these amps and it made those speakers sing like NEVER before. It was impressive to see what real quality watts can do to a speaker. 
That said, i have listed the simaudio 860a stereo amplifier (against my will). This amp is a giant killer in disguise. I felt it had more "quality watts" than my krell 402e, mark levinson 532h, krell duo 300, classe ctm600 monos, classe ca2200, bryston 4bsst3, 4bsst2, pass labs xa30.8, belcanto 600s. I have it at the top of my list in terms of overall sound. It lacks nothing and really uncovers all the hidden music that you don't hear through other amps. Very composed with iron fist bass control. I tried it with my sonus olympica 3s and the synergy is OUTSTANDING to say the least.