Audio Research REF600 MKI MKII

Can anyone tell me, is that worth to upgrade the AR600 MKI to MKII, and anyproblem with this giant AR600.Please advice.Thanks!
It is a big improvement although the 600s never quite sounded as good as the 300s. ARC released the 600 MKI then came out with the 300 MKI. They then released the 600 MKIIs. Although there was a certain grip that the 600s had that was incredible, the 300s were much more musical and are widely accepted as the best amps they made. They were never able to get the sound out of the 600 mkIIs as they got out of the 300 MKIs.

ARC has since released the Ref 300 MKII (6-7 months ago)which blows them all away. The other thing to consider is they will be releasing a 600 MKIII fairly soon.

The big problem with the 600s is the incredible amount of heat they give off as well as the power demands the have. If you do not have heavey duty circuit breakers, they will trip them almost immediately. The 300s do not have the same problems.

Good Luck!
I've heard the 600's MKI and II, and personally found the 300MKII to be sonically superior without any noticeable difference in power. I think less tubes is simpler and sonically superior. And the 300 is "only" 30K, unless you can find one used. Sounded better. Good review in TAS a couple of months ago, Jonathon Valin thought it is one if not the best amp out there. FWIW.
Hifi.. i would definately not upgrade to the mkII version of the ref 600's if there is a mkIII version in development. I would assume the mkIII may have a similar redesign of the input stage using the new J-FET topology and 6H30 driver tubes as used on the latest ref 300 mkII's. I agree with the above posters that the ref 300 mkII's do indeed sound better in most applications.. but this again is *highly* dependant on the speakers being used. Arnie Nudell of Genesis Technologies uses exclusively the ref 600 mkII's with the 200/201/300/350 speakers that he manufactures and I for one have great admiration and respect for this designer.
Mes says "I think less tubes is simpler and sonically superior".. this is fundamentally flawed thinking.. a speaker and amp combination should be mated synergistically with each other after careful examination of the speakers impedance curves, efficiency, amplifier power output bandwidth, and ultimately the SPL's the listener wants to achieve.. Pushing an underpowered tube amp into clipping during loud passages is a sure fire way to shred delicate tweeters.. as well as your ears, and is not what I would call "superior sound".. nuff said.. Jtinn, I can't imagine why you aren't bashing the ref 600's as vehemently as you have in previous threads.. is it because you have a pair of ref 300's for sale in the classifieds? Strange behavior for someone who called Audio Research affictionados as people who "do not know any better" for prefering ARC equipment. Didn't your BAT gear sell after slamming the ref 600's and promoting them? Sorry buddy but you have lost all credibility to me as an audiogon poster. Dkuipers had you pegged right.. troll.. troll.. troll..
Jimj (or whoever you are): As a matter of fact, they do not belong to me. I am selling them for a good friend who needs the money and does not have internet access. They are probably the finest amps ARC has ever made. It does not mean that I would own them or that I think they are the best out there. They are certainly up there.

I actually sold a pair of Ref 600 MKII's for another friend because he was very unhappy for all the reasons I mentioned above. They simply are not as good as the Ref 300s. Ask ARC, or most ARC dealers, or anyone who has actually owned both, they will admit the same thing.

I said "ARC people do not know any better" because the service is horrible and because most peole do not get a chance to hear some of the other products available. ARC is "mainstream", easy to audition, easy to buy and easy to sell. There are so many excellent companies out there earning a customer's business and willing to do the "right" thing for their customers, while ARC continues to take the "they are better than their customers" approach. BAT for example has some of the best customer service I have ever experienced. They pay shipping and have incredibly quick turnaround time. Another company that I have heard is like that is Thor. I personally will never do business with ARC again. There are too many "APPRECIATIVE" companies out there that I would prefer to give my money to.

I have never had any dealings with you, as far as I know, and just because I chose not to get into a personal war with Dkuipers on that thread does not mean you have heard the whole story. He just is not worth my energy or time. You on the other hand may or may not be. That is left to be seen.

I answer you respectfully even though you choose to lower yourself to a level of name calling. You also choose to hide behind an obviously phony username. Maybe you are Dkuipers or maybe you are not, but certainly you are acting cowardly. Don't you have anything better to do than study my every move? I would think spending time listening to music would be much better use of your time.
Short of driving an amp into clipping, fewer output devices will almost always result in a more stable circuit that should measure and sound better under normal operating conditions. This is due to the fact there are fewer components in the total circuit, less chance for mismatches or differences in parts tolerances, less to go wrong, etc.... Sean
Jtinn's credibility has been questioned by a one time poster. I should probably stay out of this but I hate to see a man such as Jtinn, who I have bought and sold audio gear being called a troll. Jtinn is honest, knowledgable and a valuable member. When Jtinn speaks I listen. The man knows what he is talking about. Thanks Jtinn for all of your help. It's a shame that this one time poster has caused you to defend yourself for giving your opinions. It's easy for me to see who the troll is.
It seems Jimj, that the only thing fundamentally flawed, is your hapless attempt to bring a personal agenda to an otherwise informative thread. I've had but few dealings with Jtinn myself, and have found him to be a knowledgeable straight shooter and have never questioned his credibility, as I have now yours.Pushing amps into clipping doesn't lead to superior sound?!?! Who da thunk! Thanx so much for that erudite offering.We're all richer for it.