Anyone using two McIntosh 275's in bridged mono?

I am driving a pair of JM Lab Alto Utopia speakers and am purchasing an MC2300 tube pre from Mac. I am either going to use a pair of MC 501's (500 watt mono transistor) or a pair of MC 275's (75 watt/ch tube stereo--150watt mono). I tried the MC 2102 (100 watt/ch tube stereo) and it seemed to "run out of gas". Has anyone tried a pair of MC 275's bridged to get 150 watts? How was your experience? What were you driving with them and at what volume levels do you usually listen?

Thanks for all responses,
I have 2 MAC 275 mkV amp and I have them in mono running the top end on my Infinity RS1B's. My Infinity's are 4 ohm on the top and have been powered by an ARC100 mkll @ 100wpc and a Hurricane DT200 @200wpc.
I would have to say that the more power you put into the Infinities the better. The "better" power (meaning clean-pure etc) is also a must. The Mac's can do it on one amp but tow (2) is a home run.
Just the other day (believe it or not) one of my Mac had a problem with one of the KT88's and so off it went to the dealer. The good thing is that I just converted my other amp from mono to stereo. But i hear the difference. Better and more controlled base.

Here is what I wrote regarding the Mac's in a Thread here awhile ago:

Well it's been at least 5 weeks with one McIntosh MC-275 amp in my system and now I have, for over a week, installed the second one and I now have two mono MC-275's. So let me share my experience.

I'll cut to the chase and say that one mono amp is very similar to two. One 275 (rated at 75wpc) is powerful. Two 275's @ 150 wpc is more powerful. What do I hear? In a word "relaxed". A little more control but a bit more relaxed overall.

My comments of the 275 therefore will be generally a comparison of one (1) 275 (2-sounds pretty much the same with the additions above) versus the ASL Hurricanes DT 200.

Here are the pluses of the Mac over the Canes:

First- I got my mid bass (and bass) back in spades. One of my complaints with that the Hurricane amp was that it had a higher sensitivity compared to my other electronics. I wrote in my review of the Hurricanes: "The sensitivity of the Hurricanes was much higher than my previous ARC amp and therefore, I needed to fool around with the controls on my Infinity crossover to boost the output of the bass columns. The higher sensitivity made amplification of moving coils much easier, but seemed to be bright ,a bit edgy and the upper bass/mid-bass was missing. However, I was struck, immediately, with a new unveiled sound that spread instruments wider across the stage with much more clarity than before."

I am not an engineer nor a tech so what I may be explaining to you may not, in fact, be the reality. However, with the Mac in my system it mated better with my Aesthetix Calypso and reintroduce better mid bass and bass. How this could happen and be, since my bass columns are driven by a separate amp, I am not sure. I'm just the reported.

Second- The Mac is very clear and solid. It is there in your face. There is no drift or sway and it makes you feel like the amp runs at more power then rated.

Third- It is silent. And this is a tube amp? Wow.......

Now here are the ASL's pluses:

First- Stage width with the Mac is good. With the ASL it is great. The ASL add 5-7 more (imaginary) feet per side to the orchestra

Second- The ASL Hurricanes seemed more delicate and cleaner. Less colored? Maybe?

So here I am sitting with my system, enjoying my music and the biggest plus of all (Mac vs ASL) is that I AM LISTENING.
The Mac's have been on without a hitch. Knock on wood. However, just the feel makes me certain that the Mac's are far better in construction (far) then the ASL.

Remember, however, ASL has come up with a better Hurricane and I have not heard it or seen it but I must believe it has to be more reliable then the original. I just could no longer live with break downs with hurricanes.

Finally, if anyone is thinking of a Mac I say "YES". It is quite a wonderful amp with some character and style and plenty of power. And it keeps on running.......

P.S. I have not yet listened to the Mac with better KT88's or x7's or t7's which I plan to as I expect this would provide an overall better sound.

Hope this helps...

P.S. I have upgraded the 12ax7's and at'7 to it!!

Rick (RWD)
Just FYI guys, it's 90/180 watts, not 75/150. McIntosh just wanted to keep the '75' badging but the pwr. tranny is now 490V ;-)

Rick, did the soundstage improve after you changed the tubes?
Yes, Neil. It did!

thanks guys. the power sounds like it will be enough. i think i am going to go this route.

Let me know what you find out. I have a pair of JM Lab Alto Utopia too. Thanks.

I agree with you about 1 x MC2102 running out of puff. Try mono blocking the MC2102's in parallel or bridged 4ohms and you wil be blown away with the imporvement in every area.

I have had the MC501's at home and 2 x MC2102's blows them out of the water.

BTW, The C2300 is a great pre amp. I have one at home at the moment.

BTW, I have not heard the MC275.
I'm using a pair of bridged 275s on my Everest 67000s and I've been very pleased with the results.  I had a little bit of worry beforehand about whether they would handle the demands of twin 15s but the proof is in the pudding.  Even at painful volume levels when prodigious amounts of alcohol have been present, they have kept the bottom end completely under control and at those volume levels, there's still no harshness in the high end, thanks to the tubes.  And they are completely silent.  I have considered going to a 452 and saving a little dough, but why take a chance?  When choosing against a 452 makes sense, something is very, very right.