Audio Research REF600 MKI MKII

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..