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Mc 240 vs. Prima Luna

Good morning all, hope everyone is well and ready for the holidays. 

I may need someone to talk me away from the ledge. (fairly normal state for me these days).

Story is this. I have been saving to add a second McIntosh 240 to my system. I have one now that does a fine job powering my Klipsch Heresy IV's. It was recently refurbished by Audio Classics in Vestal NY. (by the way, can't reccmomend them highly enough, especially Ryan).

Anyway, I'm getting close to being able to pony up for the second 240. Plan is to bridge them in mono and have 80 WPC effectivly. 

However.... I have been reading much about the Prima Luna's. Modern.. Warm... ability to roll several tube types.. sweet mid, good low end..

Do I stick with my original plan, get the second 240, (built in the US, tank like construction, known sound and cool factor).

Or do I chase the neat new shiny Prima Luna's ?

Any thoughts are welcome..

Doug

 

 

doyle3433

Showing 2 responses by charles1dad

charles1dad's avatar
charles1dad
10,250 posts
 

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 

charles1dad's avatar
charles1dad
10,250 posts
 

@russ69

"Although mono-blocks are better than stereo amps, bridging a stereo amp is not the same thing as a pure mono-block amp." 

I agree, the key point is bridged amplifiers are not the equivalent of a true  mono block pair. 

In addition as the late almarg  would politely explain,  bridged amplifiers will see 'half' of the speaker's impedance.  8 ohm becomes 4 ohm, 4 ohm load becomes effectively 2 ohms. As a result,   the bridged amplifiers are asked to drive a more difficult impedance load.  Better to obtain genuine mono block amplifiers. 

Charles 

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