Audio Research versus McIntosh tube amps: anyone experience or compare both?

As stated in the title of this thread, considering both brands.  I'm looking for a new or near new tube amp to run my Joseph Audio Pulsar's.  Have been using a Pass XA25, which sounds a little lean with this speaker.  Looking for a touch of tube warmth and bloom, but still good detail.

Considering a new McIntosh 275 MkVI or possibly a preowned ARC Reference 75SE.  New ARC costs more than I want to spend ($6K range or less).  Preamp is ARC Ref 2 MKII BTW.

Would appreciate any insight for those who have experienced both.  Thanks!


I have an audiophile friend who switched from pass lab XA160.8 to ARC ref250. Paired with ARC ref10 pre amp he and I just love how they sound with Magico S3. If you like details and “fast” response with a little tube bloom then ARC is one of the very few maker who can make this balance meticulously. Macintosh IMHO is more “classic” tube sound : “musical” (=slow transient response so not too much details ) but each to their own. 
disclaimer : current user ( and big fan)of ARC ref10 / ref 160 mono mk2 , I had used CJ / Counterpoint / Jadis / Mac / Kondo / Manley in the last 25 years and these are the best tube pairs I had ever used. 

Maybe try an ARC VS110 or VS115. Not an ARC reference level amp, but might have that warmth you are looking for while still retaining that ARC sound. Uses 8 6550 tubes and easy to bias. I also agree with the Ayre recommendation. I moved from the VS110 to a Theta Dreadnaught II (which like Ayre is a zero feedback Charlie Hansen design) and the bass drive is fantastic with very detailed mids. The Theta also has 225 watts/450 watts into 8/4 ohms vs the ARC rated at 110 watts. Both the VS110 and the Theta are available for around $2,500. 

Used ARC REF150se sometimes trade for $6,000 or less, if you need more watts.  I own one.  Great amp.  I think undervalued on the used market, but that's the market.

Are the fans audible in the newer bigger ARC amps like the 150?

Also, is the biasing procedure complex?


Convenience has value IMO.

I have mine on low (3 available speeds) and can't hear them.  Things seem to stay cool enough.  Might need a higher speed if your room is hot, but them you wouldn't want the amp on for super long anyway. 

Biasing is pretty easy.  I think the VT100 is known to be one or the worst ARC amp to bias.

It's a pretty great amp.  I considered replacing it with a REF160S, but they are quite heavy (close to 100 lbs?) and I suspected the 160S will be replaced or augmented with a new amp that uses the KT170 tubes.  I think I am correct about this, as the 320M became the new 330M with KT170 tubes.