You don't mention impedance curve, which can be as important as sensitivity. If you want maximum sound levels in a room that size it will be hard to find any tube amp that will give it to you. Part of the equation of sound level is reflected sound waves and they will not know what part of the room you are using if the whole room is open. I don't know you feel about near field listening but in a room that size it might be your best alternative with tubes if you like loud levels.
Take a look at VTL, they have tube amps going up to at least 750 watts/channel. Havent heard any VTL in years so I cant give you any help there but in the past they've always sounded excellent.
What sonic changes are you hoping to achieve?
I really like the combination of a great tube preamp with a solid state power amp. I get what I feel is tube magic with a solid foundation. Is there just something about the Krell you don't like?
I'm with Rgs92, try a nice tube preamp in front of the Krells.
Bob Carvers new tube amps are supposed to be very good, 180 and 350w supposed to drive anything.
I also agree with Rgs92. Have excellent results, tube magic and solid bass and dynamics with my tubed Joule Electra LA 150 Mk2 preamp and Fosgate Signature phono preamp and 250 watt/channel solid state Belles 350 A amplifier.
thanks everyone for the input, it sound good Krell with tube pre and photo, it is that i have krell for over 10 years and thought is time to have a change.
i am waiting for my Aesthetix Callisto sgn. to arrive.
Thinking of powerful Tenor 175S, they said is the best power amp. i am looking for a used one, too much money for a new one.
I think audiovalve challanger 180's would be worth a look;el34,6550 or kt88 choices and power out ranges from 150 to 180 watts;I am using these on my soundlab m2's with very nice results.
VTL...nice...but for my money, the most musical...in this sense, not pejorative, but the ultimate compliment...Valve Amplification Amps (VAC by Kevin Hayes)...best voicing, for my taste...warm, rich, inviting...beautiful staging, low level resolution without that 'etched' quality that can tire or fatigue.
At least give them a spin...they are, in a word, Marvelous...
VTL 450 wpc and up. Wolcott is a good one too. Do you live in a warm climate? If so you may need A/C at least in the summer. I have a Callisto Partial Eclipse with two power supplies and it by itself heats up my room pretty quick. Although my room is smaller and is upstairs. I would like to try some high powered tube amps as well but don't have A/C at the moment.
I think you should wait till you get the Callisto to decide on amps. I also went from a Calypso to a Callisto and you are in for a treat. You may decide you do not need to switch amps.
I went from FPB 600s to ARC.
Depending on your budget, there is a wide variety to accommodate your needs and ARC tends to lean towards SS when it comes to bottom end control which is a real nice attribute.
I tried the VTL's as well and preferred the ARC based on the bigger model ARC I settled for. NO tubes will have that staggering control of what the Krells can provide but it was a compromise I was willing to take to fill the other avenues that the ARC provided. Good luck
Thanks for all your feedback,
Do any one have Ayon Orthos ii? Is much cheaper than Tenor for a demo set. Ayon Orthos ii is 250watts price about $18000 vs Tenor 175s probably around $33,000 demo. i am leaning towards Ayon. Will try one in Seattle store.
There are a pair of VTL sigfrieds for sale in Seattle on this site. Those would have plenty of power and sound fantastic. I have heard them powering a pair of Wilson Alexandia at a dealer some time ago and was very impressed. I'm not a fan of Wilsons but that combo was sweet.
I have no assosiation with the seller but suspect that it is the Dealer that I heard them at.
The VTL Sigfrieds are sweet if you have the dough. I'd have to second that option. Manley also puts out some pretty powerful tube amps that should be a bit cheaper.
I see you have experience with Joule Electra,
there is a sale in audiogon VZN220, what do think of this mono block amps.
Do anyone have this Joule amps, i read in audiogon some same is problematic,
i know tube amps burn out tube fast.
i have now Aesthetix Callisto Eclipse and is very good combination with Krell FPB600.
But the asking price of VNZ220 looks attractive but is almost 9 years old.
Any comment anyone?
The two best amps I have heard are a valve and a high powered digital. Valve amps shine on vocals; Dianna Krall, Sinatra, Adele all sound divine. I was with a guy who had never really heard a valve amp before and we played some of that stuff on the digital amp - very good - but we put my valve amp on - his eyes went wide - he couldn't believe how much better the vocals were - so real live and present. But just to make the point it is source dependent we put on some Dire Straights - Private Investigations. The voice is at low volume in that track so you really have to wind it up to hear it over the music which tests the dynamics and power of your amp. Nice on the valve amp - no question - but when we put the high power digital on - no contest - the dynamics of the background and overall ease of the entire performance was way better.
Bottom line here - what do you listen to - rock, heavy metal , classical or a wide variety of music - get high power SS. Listen mostly to Jazz and vocals (as I do) - the valve vamp is the go. I also listen to a lot of 2ch HT so the valve amp is out for me - darn - but it is divine.
Oh and I want to add both those amps in the comparison are ultra high end - both those amps easily blow away MAC 501's for example which aren't easy.
You are correct, i still want to keep my Krell for HT, and listen tube vocal and rock and Pop SS.
i wanted a SET but manufacturer, like Cary, Ayon said it have not enough power to drive my Hansen Emperor which is 87db, 6 ohms. Probably before i buy any tube amps i need to go for an audition, In Vancouver,BC there is no dealer carry Ultra high end tubes amp.
Happy New Year to you
Auditioning is the only answer.
If you do not play highly dynamic music and stick to music valve amps shine on I at one time even used an 8W amp SET - (Trafomatic Experience 2) on some 87db speakers no problem so power is not really an issue.
However the very best valve amp I have heard - and I have heard a few these days - is the amp I mentioned previously:
The guy built it as a special order for me but was so impressed with how it sounded decided to make it part of his line up. The issue though is the guy that makes them is good - and plenty of people know it - so there is a huge wait time - mine took nine months. But if you want the best - that's it - and at 45W is quite loud enough. Of course not as dynamic as the 500W SS I also mentioned and on some music you will notice it but still quite good.
The problem buying from so far away, shipping and service takes long time.
BAT may be worth exploring. I heard King V2 driven by VK-150 to good effect
Audio Research....but ya might wanna keep the Krell. Should have picked up a KCT preamp...tube sound without the tubes!
Have you considered having your Krell rebuilt. I just had that done in November and for a whole lot less than the cost of a new amp, I had Krell rebuild my 30+ year of KSA-80B. Its just marvelous. So musical. They put new caps in in and a few other parts, adjusted the bias and tuned it up. It have never been serviced before. And with Krell, two things you can count on, they will drive low impedances (mine is one ohm) and they early ones do sound nice. If you have had yours 10 years, they probably sounded good to you, but could use some new HQ components.
Be careful buying VTL used, they treat "used amps" different than those purchased new from a dealer.
Warranty if any is void and depending on age repairs can easily get cost prohibitive
Tubes are more fun, make music sound like it's supposed to, and make you a better person. Also, note how many non tube amps claim to have "tube-like" sound, which means, generally, they don't.
C-j and Quicksilver make some powerful tube amps.
check into the mastersound mono blocks.