Been there, done that, bought the T-shirt...

Posted by Al Sekela (A) on September 17, 2006 at 15:24:56

In Reply to: Maggie 20.1 with 2 Amplifiers posted by Peter_S on September 16, 2006 at 13:18:22:

Actually, my experience has been with MG-20s, but the problems are the same.

I tried to match OTL monoblocks on the midrange/treble with a solid-state stereo amp on the bass panels. I had the levels matched, and visitors commented upon how seamless the presentation was through the midrange.

Then I got a pair of Gilmore Raptor switching monoblocks (rated at 500 wpc, but with very low ouput impedance), and rewired my already modified crossovers to go back to single channel per speaker operation. The crossovers mimic the stock except the treble feed bypasses the stock midrange high-pass capacitor bank (the speakers are effectively tri-wired), and I added R-C filters to the outputs of the stock bass low-pass elements. These changes were made prior to adding the Gilmore amps, but I want to be complete about the comparison.

The sound with the Gilmore amps is so much better! The mid-bass through midrange palpability was increased very much over the bi-amp setup. The treble is clean and pure. The bass damping is far superior to what it was with the InnerSound ESL-300 bass amp.

What Maggies really need is the highest damping factor you can provide. Your proposal divides the power requirements among the amps, but does not increase the damping factor of any one of them. It will not result in improved performance, and will consume many hours of your time in trying to make it work.

The Wolcotts are fine amps within their power limitations, as Henry Wolcott is a genius who put his feedback tap inside the output transformers. This makes his amps stable with electrostatic speakers, but does not overcome the limitations of tube circuits in general. You should be able to get good modest performance with these amps if you don't care for the sound of the Odyssey Stratos. Certainly, either type of amp would be good to break in the Maggies.

Modifying new speakers is always a personal decision, because doing so voids the warranty. However, I would consider bypassing the midrange high-pass capacitor bank for the tweeter feed and the stock Magnepan mid/treble connection hardware, fuses, and crossovers. The Gilmore amps retail for $5000 per pair, and are a bargain for Magnepan power.

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