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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
lewinskih01
906 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
pdreher's avatar
pdreher OP
1,185 posts
 
Lewinskih - Yes I will be using RCA cables, so you advise is pertinent... thank you. One question though.... when you said add "V1" tube to the signal path, what do you mean by V1?
Thanks,
Paul
pdreher's avatar
pdreher OP
1,185 posts
 
Stuck a deal for a MC275 MK V. Really looking forward to rolling tubes in my 1st tube amp!
tom_hankins
928 posts
 
Good luck with your purchase! Hope it works out for you, I'm a big fan of the MC275.
rgurney
279 posts
 
Pdreher - V1 is the first small signal tube(marked on the chassis), that the signal encounters in the amp(when using RCA cables), therefore it has a great effect on the sound. Balanced sections are very important as is the quality of the tube. The 12AX7's affect the sound the most, followed by the 12AT7's. Roll them in that order, if funds are tight. Good luck and have fun.
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