If you like the sound of the Mac get a 2nd one. The Mac tube sound is very nice and lush. I don't think you can get the PL to sound as tubey and 3D. Just my 2 cents.
It’s pretty simple, NONE of the Macs sound worth a crap in Mono, Even built to be just mono. I tried a few times with mods and a few different thing. Nothing could get close to the sound of a Samra MC240 in dual mono or stereo mode.
The problem I have with most rebuilds on 240s is the cheap polly caps (yellow) that Mac NEVER used. It just kills the way a 240 sounds.. It takes paper and oil caps a few carbon comp resistors checked/swapped and a PS upgrade.
Don’t compare a yellow polly rebuild to a proper PIO rebuild.
Surplus Russian PIO KY44 and 77s will last 50 years if they last a day and sound better than the old bumble bees, (not the black beauties). Compaired to the pollies there is just something missing in the mids and they change the way my ribbon tweater sound. I’ve used the same types of drivers for a lot of years, 70s I don’t change. Small ribbons and planars.
You want 75-85 watts per channel use a MC275 and get REAL happy. It will blow the doors off a 240 and as for the Raven, I’ve never heard one. I’m sure it’s well built. It’s also 20 watts per channel. Apples Oranges. I’d doubt VERY much it would sound better on the Hershies. At least VS my MC240s.
61-70 MC275 you can get close to 90 watts per channel and a MAC sound.. It’s like no other with a set of GOOD 6550s or GL (type) KT88 and Telefunken valves Nothing sounds like that. It’s a Macs.. Again PIO and keep the Black Beauties, check the resistors and there are 4 you need to change and a PS upgrade.. 90 watts per channel.. Good bass! LOL better than anything mentioned here.. WAY better..
The cool thing would be to run a good 240 for the mids and highs and a 275 for the bass, If they are bi ampable.. THAT will really get LOUD and VERY clear..
You want to LOOK really cool get a MC225 TOO.. :-) I line mine up all pollished and I get happy. MC225, 240 and a 275 on a white tile counter top in the kitchen, (I built it too.:-)) is a pretty cool picture..
50 years with Mac, I love um’
Doubling up your existing amp will not gain much. You'll have the same sound and 3db more power, just not worth the trouble. Although mono-blocks are better than stereo amps, bridging a stereo amp is not the same thing as a pure mono-block amp. A Prima Luna and perhaps some tube rolling would keep you busy for a while.
I disagree that doubling up the current tube amp won’t gain you much. I have a pair of VAC 200iQ tube amps, and running mono is a clear and significant improvement over a single amp in stereo mode. I have 96dB / 8 ohm speakers, so the increase from 100 Watts/ch to 200 doesn’t seem like it should be meaningful. But very clearly, the pair of mono amps is much better - and it’s not always just about raw power, anyways. Also heard this same effect with the same amps in my friend’s system. And 3dB is a LOT, when you’re near your preferred listening volume in a familiar system and you’re an audiophile. "3dB isn’t much" is good forum fodder for the HT guys.
With op going from 40 to 80 watts, I’d be surprised if the improvement isn’t significant. I’d stick with the McIntosh plan.
I am a PL integrated owner for almost three years. I have used tube amplification for decades. This is the best tube amp I’ve ever owned in terms of musicality and ease-of-use. What’s especially appealing is the auto bias, ability to change power tubes for your sonic preference and the amp will shut off if one of the power tubes red plates or gets funky. To me, those features eliminated a lot of the hassle of owning a tube amplification system. I also like the sound presentation which is tonally dense with great ambience and dynamics. The power tubes can change the sonic presentation from lush and warm to robust, fast and very transparent (EL 34 versus KT150) I would say the Macintosh brand has a very appealing type of case work with its blue meters and the PrimaLuna cannot match that if that is important to you.
"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.
Yea, just not with 240s in parallel or in series, you can run the 240 and 275 EITHER way. A MC275 were made for Klipsch Honestly a MC240 stacked is for PA, it will run the speakers just fine, they just won’t be the sweet sound of a MC240. They are VERY special one way but not EVERY way. They like 8-24 ohms too. They just sound better.
50 years with Mac, I’d be changing back to a MC275 before the bill started to fade if I was looking for true Mac sound.. Or better yet try a Cary V12r.. LOL Second best amp I’ve ever owned.. What a wonderful amp AFTER I worked it over.. I love it..
I’ve had VTL 750s and 1250 Wotons here a few times.. I’ve listen to a LOT of amps and did a lot of work on others..
A real nuget is a MC225 with just a PS upgrade and a few PIO caps changed for some of the non MPWs but NO yellow pollies.. They use MPW metalized polypropylene, DON’T you dare change them. They are the wonderful sound of the little MC225 amp.. Just make sure on the resistors and check for tolerance in the caps.. Virshay coppers are a GREAT resistor.. Pure (?) too I think it’s Pure..
I've heard the nasty downside of bridging, with solid-state amps which I loved in stereo mode (Phison A2.120 SE), and they lost their sweetness in mono/bridge. But tube amps can be a different story, probably in part because you can change taps to manage the different impedance. Also they won't just "double down" the current & power while straining the PSU and output stage. My VAC switchable mono/stereo tube amps sounds by far the best in mono.
But @oldhvymec has experience with the MC's, doesn't like bridging them, and that trumps theory. So that's a solid vote against mono/bridging the MC240...
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.
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.
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.
@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.
I am now curious what my system would sound like if I used my one of my MC275 amps to power the lowers on my speakers and one MC275 to power the mids-highs in my speakers. It might be worth trying this setup to run the MC275s in stereo instead of mono since my horn speakers can be bi-amped. I can’t try it for two weeks though.
I would sure give it a try femoore12. Just so everyone knows, I do NOT use valves to run bass. 300hz and down is SS.
80hz and below is normally GR OB servo subs
100-300hz is direct coupled to 12k class Ds and 6, 8" mid bass drivers per column and I use a 2496 active XO.
300hz up is all valves and I use a hybrid line source of 8" Monsoon planars and normally a single Aurum Cantus ribbon tweeter. I use a lot of their drivers. They have a great AMT too.
I do have one system I listen to when I’m in my work room. MC225, MX110z, Sony ES777, Thoren 124 and a pair of tricked out Infinity RS4bs. That system is old as dirt, but the system I listen to most of the time.. The only place I use tubes for bass and it is the smallest Mac (25 wpc) I own. it’s funny. Sure sounds good.. It’s actually my favorite for itty bitty, Just don’t tell anyone.. LOL
As a McIntosh and PrimaLuna owner, there could be pros and cons to either depending on what you value as an owner.
Warranty: 3-year warranty if you register it. Also...made in China for what it's worth.
I plan on giving this a try once I get home in a couple of weeks. I also use a servo sub for everything lower than 80hz. I love the combination of the servo with my horn speakers. I have been thinking about upgrading to a pair of the dual servo flatpack from GR Research.
My apologies for discussing something other than you Mc240 vs Prima Luna question.
So coincidental that those were my two choices for my first foray into tubes. In the end, I went with Primaluna. I do have regrets but it's not like can't get one down the road. The problem is that the Primaluna is so damn easy and fun. It's got it's own branded sound: warm, musical and ballsy...a little lacking in the final bits of detail but very good with 7581a tubes! I have the Evo 400
here is a photo of the guts of a Mike Samra modified 240. The 240 has the best output transformers Mac ever built including to this day. Run it stereo. In fighting trim it always makes 50+ wpc, enough w Klipsch to deform your head. The Dead used 4 MC240 in mono for the early days PA.
Buy another, send best one to Mike in Michigan, get it back…break in those PIO caps…magic…..
Thank you everyone for the thoughtful comments, suggestions, advice..
I do completely enjoy my current set up, and I am feeling the additional 240 may not be the best use for my dollars. Perhaps I can split what I’ve saved and upgrade elsewhere. I wouldn’t mind upgrading my pre-amp. The old NAD seems out of place. Maybe I go for something more period correct like a MAC C 26 or 28..
Also found some great deals on some phono pre-amps I’ve been lusting after from Sutherland.
Don’t think the Mac has the build quality of the PL also you see a ton of Mac gear for sale every day PL not so much. This would indicate to me the people who buy PL stay with them and the Mac people move on to something else. I don’t agree with the Person that said Mac hold more value than PL the Mac can be 2-3 times the price.
Here are a few facts.
You might want to incorporate those facts into your reasoning.
Could it be that 10 times more Mac gear is sold than PL?
Bet that's the case.
Also Mac gear stands the test of time and a lot of the gear on the market is over 50 years old.
PL not so much that is gear that get binned or trashed.
So you are validating your purchase and you like the sound well good for you.
I personally do not like PL or MAC just not my thing.
But from an investment standpoint I would buy a 30 year old MAC at 2 times the PL price new.
Don Sachs used to do mods to Macintosh gear. He now builds amps which he says are far better sounding than any Citation or Macintosh amp ever built. Prima Luna is okay, I have one of their amps, but if I wasn't building my own amplifier which is nearly a dead ringer for Don's amp, I'd buy one of Don's amps. I do have his preamp.
That "same factory" (Zhuhai Spark Electronic Equipment Co., Ltd) is owned by the Chinese government. Is that where you enjoy seeing your money going to these days? Deal breaker for me!