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Tubes for Magnepan’s.

I think next up on my acquisition list is a tube amplifier. I'm not looking for the be all end all, cause I don’t think there is a definitive "Best", so am looking for as good as I can get for $3-4k.


Because tubes drive speakers so much more efficiently than solid state I am only looking for 40-50 watts to drive my modded Maggie’s, 1.7i's. (Or what you have when you add a new crossover and planer tweeters to 1.7i's.) Maybe 2.7x? I haven’t settled on that yet. And I have some Zu Dirty Weekend's upgraded to the max coming in in 2 months to replace my KEF's.

Anyway, I haven’t had a tube device since my Halicrafter short wave radio, and reviews are not the same as advice from people that own something. There is a Rouge Audio dealer in my area, last I looked, (opps, they no longer carry them), so I may have to go to another market to hear something, or get a try before you buy from a manufacturer or dealer.

You folks have taught me a lot, and I think asking users is the right thing to do on this change in direction.

Thanks in advance.
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jhills
610 posts
 
I am driving my 1.7 Maggies with a Rogue Cronus Mag II and have no problem at all. I no longer feel the need for loud and head pounding, so I seldom turn the volume nob beyond 25%. At moderate levels, maybe 65-80 db. the combination of the 100W Rogue with the 1.7 Maggies, is incredible. 
Sometimes I switch out the Rogue with my old GFA 5500, ADCOM (200/350 W} mixed with my old Audible Illusions Modulau II pre-amp and that combination matches with the little Maggies as well, but the sound is not quite as full and open as with the Rogue.
Not sure if the 100W Rogue would be enough for the larger 3.7 Maggies, but with the 1.7/1.7i it works great.......Jim
decathlon1991
212 posts
 
I use to have the Magnepan 1.7’s. I used the Cary Audio SLP05 preamp with the Ultimate Upgrade and a Cary Audio CAD805 AE Monoblock amplifiers (Pure Class A 70 Watts with the 211 Output Tube). The sound was incredible. Remember, it’s not so much about the watts, it’s about the dynamics and stored energy from the capacitors that can handle the outburst of energy from whatever music you are listening too. The Cary’s were perfectly fine. I wasn’t looking for concert blow your eardrums sound. Also, not all big tube amplifiers run extremely hot. McIntosh MC2301 Monoblocks are not cheap but put out 300W of power and due to the design, runs no warmer than most solid state amplifiers today. The tubes are spaced out with ample spacing in between on the plate. Hope this helps.
drbarney1's avatar
drbarney1
172 posts
 
See https://www.youtube.com/watch?v=OiXAIz0EI48&t=50s I use these with Magnepan 0.7s with DWM bass panels. An 833A is more than powerful enough to make Magnepans too loud but the 833A has a very rich sound. You only need 1000 Volts on the plate with the grid through 600 Ohms of headphone amplifier transformer connected between the grid and the same ground as one of the terminals of the cathode heater putting the grid at zero voltage bias. The cathodes need very pure DC; 9 to 10 Volts at 10 Amps so the best way to begin is to use a couple of car batteries and about 0.4 Ohm dropping resistors. If you build a complete amplifier, a 46 SET with a Lundahl LL2756 output transformer for 5k to the plate of the 45 and 600 Ohms to drive the 833A you will have an ideal amplifier for under $2000 in retail cost parts. Let me know if you want help building such a project so you can know it will work.
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hwr
17 posts
 
The most economical approach is certainly SS amp and tube pre. SS amps typically will deliver better bass too.
You mention wanting the option to play a little bit with the tubes. I understand completely and I love my Eastern Electric Mini Max pre-amp. It's a tube rollers delight, sounds great, and offers incomparable build quality. It utilizes the easily obtainable 12AU7, of which I own over a dozen pair of various brands. Talk about flexibility to tailor the overall sound of my system!
I bought it used a number of years ago from a fellow A-goner and have loved every minute I have spent using it.

Good luck, have fun!!
william53b's avatar
william53b OP
211 posts
 
The one thing that is already done is changing the speakers over to bi-amp connections, so I can indeed drive the woofers with a ss amp and the mid-hi's with a tube amp. Experimenting with adding depth to the baffles today to improve bass. I think this has been disguised as frame bracing by other moders. It is after all, and open baffle design.
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