Mc 240 vs. Prima Luna

Kevin Hayes discussing his VAC 200 IQ amplifiers With Hifi news.com, 

"With respect to overall power, it's generally been forgotten that very soon after the inception of the KT88, nearly 70 years ago, the GEC/Genalex data sheets showed a 100W/pair operating point in its application circuits' says Kevin. 'In practice, we find that some pairs of KT88s will exceed 100W. The KT88 delivers exceptional sound under these conditions and, in our circuits, average tube life is quite good – typically 6000-8000 hours.'

VAC's custom output transformers are also core to the amp's 'real world' performance. 'In stereo mode the taps are effectively for 2, 4 and 8ohm; in mono, a parallel operating configuration, they are effectively 1, 2 and 4ohm. So, in mono mode [as tested here] the maximum power, lowest distortion, and widest freq. response occur into a 4ohm load on the top tap, which is labelled "4-8".

'Most audiophiles will try more than one tap to see which best suits their loudspeaker (with its varying impedance curve), so we label the taps with a range rather than a single number'.

So it seems in "Mono" (Bridged) mode the amplifiers are seeing 1/2 of the speaker's impedance they encounter when in stereo mode (As almarg described).

Anyway the bottom line is what the listener hears and likes.

Charles 

The Heresy sounds better with tubes, if you want verification go to a Klipsch forum.

 I am wondering why you need to add another amp, you already have more than enough power unless your room is the size of an auditorium. They are a very efficient speaker.

IMO save your money and buy better speakers unless all you listen too is rock. FYI I have Prima Luna and they are very good,the Hersey 4's I own are boxed up in the closet.

Buy what sounds best to you.

Klipsch speakers and McIntosh amps are a fantastic pair. I say go for the MC240 and run them mono. I run my 275's mono and love them. 

Here is something I would try if I used horns, I don’t. Not because I don’t like them. I just had to make a choice on what I was going to use. I went with domes 50 years ago and small planars/ribbons 30+ years ago. I haven’t tried a bridged Mac on your speakers. For all I know it might sound great..

8-84" of push pull ribbons drivers don’t sound so good though. I might have spoken out of place.. Do a listen on a single speaker bridged at 80 vs a mono or stereo at 40 watt, they sound different (stereo vs dual mono vs bridged). I’d try it series and paralleled but stick to one speaker.  I’ve done it both ways with a 275 it does make a difference for high frequency ser vs par and clarity with spl..

A MC275 with a healthy PS will push a 1 or 2 ohm load. You can fry eggs on them too. BUT they keep on running as long as you keep a fan on them. I’ve seen Macs keep on driving Infinity 9.0 Kappa and only get hot, when other amps were dropping dead like flys with that speaker. Krells, Mac SS MB, Mac MC23 or 2500 Threshold, Pass, Modded Son of Ampzilla and a Mac MC275 no problem.

Regards

@oldhvymec makes some really good points.  The MAC tube amps bridged to mono never sound as good as they do in stereo. Have tried it myself several times with a 240, 225 and 275. The Klipsch are pretty easy to drive. As far as the PL amps go, would also agree with the other posters, not was warm sounding as the MACS. 

What the original poster may want to consider to spending the sum on powered subs, and let the MC240 handle the midrange up.