McIntosh MC275 original amplifier

Category: Amplifiers

My system consists of an Original McIntosh MC275, Placette passive pre amp(3 input model)Oracle Delphi turntable,Grace 707 tonearm with custom phono cable, Denon 301 II MC cartridge,three different cd players,Klipschorn and Focus 20/20 speakers(depending on my mood)various power conditioners and two Blue Circle BC86 MKIII power line pillows. After trying many different tubes I finally found a combination that works to my satisfaction. If you have any suggestions or comments, I am open to hear them. I use 4 Genelex KT88 power tubes,one Amperex 12ax7,two RCA 5814a Black Plates,two RCA 12BH7A and two Telefunken 801S tubes. It took this combination of tubes to really get my amp to sing the way I think it should. Obviously the Telefunkens were great, but the biggest surprise to me where the inexpensive RCA 5814A Black Plate tubes in the 12AU7 sockets. By the way the Telefunkens are in the 12AZ7 sockets.
Wow...good work.
However, I have 2 new MC-275mkV's and the only three types of tubes that are noted are: KT88, 12ax7's and 12at7's. How can the 5814's, 12bh7a's etc go in???

Rick (RWD)
Rick, the original 275's had two 12BH7 slots and had a total of 8 twelve volt tubes. As the 275 changed throughout the years (1961), it has been redesigned, to only have 7 twelve volt tubes & to have just 12AT7's and AX7's.
Hi Sid! I wrote in one of the threads the following regarding two MC 275's vs ASL Hurricanes:
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.

Well Sid that was it...I am very happy with the Mac's

Rick (RWD)