Tubes with Magnepan Atma-Sphere

It ain't going to be cheap.

Leave the Atmos on the top, and add seperate amps for the bottom, the OTL's are not going to be a good match for the bottom end. Get a great SS amp for the bottom, (can be a chore to integrate, or a big Manley/VTL/ARC 300's toob amp pair for the bottoms and a great X/O. ARC or Bryston for the X/O section.

Or throw out the Maggies, move to Soundlabs and subs.

You do have a set of subs for the big maggies?

loon

I haven't heard the A-S with Magnepans, but I have with other speakers. No recollection of bass shyness. The A-S are purported to have some of the better bottom end, especially when comparing to other tube designs.

The Wolcott P220 monos do a wonderful job of controlling the bigger Magnepan & Soundlab panels. at 220 watts, driven by 8 EL34 based tubes, they have ample power and do not lack at all in the bass department. The most recent vintage of the Wolcotts are now being produced with wider bandwidth transformers than earlier models, and they really allow the Magnepans to open up and sing. I use them with the 3.6R and am delighted with the results. At a little over $10,000/pair new, they are not cheap, but I believe they are a better match for the difficult Magnepan load than an OTL based amp. The Atma-sphere MA2 might work out they way you would like if you consider using Autoformers to raise the impedence load the amp is seeing.
I can tell you that I have no need for a sub in my 17 X 23 X 10 room using the Wolcotts.

I have had an opportunity to listen extensively to the MA2 amps driving Avalon Eidolons and can attest to the fact that they do not lack in the bass arena at all. A wonderful amp that seems to get everything right.

If you have the opportunity to do so, try to listen to both the Atma-sphere and the Wolcott driving panel loudspeakers.