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McIntosh MC 275 Mk IV or V with Harbeth M-40.1?

I've had my Plinius SA-102 for longer than any previous amp (almost 3 years) and have been very satisfied with it's reliability, musicality and build quality, but I'm very intrigued with finally trying a classic tube amp.

I listen to classical, jazz, vocals & acoustic rock at moderate volume levels, so I'm thinking the 75 WPC of the McIntosh MC 275 (mk IV or V) would work fine in my 15' x 21' x 7' basement set up. The Harbeth M-40.1's sensitivity is 85dB/W/m, 6 ohm nominal. Suggested amplification: >50W (Stereophile's review of the M-40.1's noted excellent success when driven by a 35wpc Shindo push-pull amp)

I've researched other tube amps from Rogue (M120's & 150's), VTL (ST-150), Manley (Snappers), Cary (120S), Audio Research (VT-100 MK III) and Quicksilver (V-4's). Ultimately I'm leaning heavily towards the Mac MC 275 (Mk IV or V) due to its not being a monoblock, it's a classic unit with excellent build quality and good resale value, and it's known to be reliable and is easy to bias.

Preamp is an Aesthetix Calypso with NOS tubes and my sources are digital and FM.

Comments from those experienced with later model McIntosh MC 275 and/or Harbeth M-40.1's would be appreciated.

Thanks - Paul

128x128pdreher
rwd
695 posts
 
I have a (2) MkV (Mac 275) along with the Aesthetix Calypso. The combination of both is quite good. I have two Mac 275's and they are used in mono. However, I had also used one on my system with very good results.
The Mac is a bit dryer then the Aesthetix and therefore they complement each other. My 2 cents!

Rick
(RWD)
pdreher's avatar
pdreher OP
1,206 posts
 
Rick - are you using stock tubes in the Mac 275... and if not, which ones are the most critical to replace as far as sound quality goes? I use select NOS tubes in my Calypso and the difference is night & day.
vernneal's avatar
vernneal
438 posts
 
The McIntosh has the highest resale of any electronics.
rwd
695 posts
 
I am using Telefunkens in the 12ax7's and 12at7's bought here on 'gon.
Big (positive) difference. I have not changed the Kt88's butI plan to. Neil (one of the great cotributues here) knows quite a bit about the Mac 275.

Rick (RWD)
lewinskih01
909 posts
 
I believe Rwd is referring to Nsgarch when he says Neil. He is indeed knowledgeable about the 275.

I also have a 275 mk IV (I love it), with rolled 12AX7 and 12AT7. These signal tubes are said to have the highest impact on sound quality. I have not yet rolled the KT88 so I cannot really comment from personal experience.

About your question: since your preamp has RCA and XLR connections, I'd say if you plan to drive the 275 from the XLRs, then either the mk V or mk IV would be the same. If you are going to drive it from the RCAs, I'd say go for the mk V. The mk IV has volume pots in the signal path when driven from RCAs, which allegedly degrade the signal. Both the mk IV & V add V1 tube to the signal path when driven from RCAs as compared to XLRs.

FWIW, I drive B&W 804S which are 90 dB speakers, and I'm happy. Can't claim to have tried a gazillion amps, though.

My two cents. Hope it helps.

Horacio
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