I have Maggie MG 1.6's - need amp advice

Mrtennis...At least with Maggies, the "quality of sound" delivered at a five watt average power level (about six volts rms into 4 ohms)is better when it comes from a powerful amp although one would think that 100 watts would be plenty. That's my experience, and I am not alone. I haven't a clue why this is so.

By the way, you could actually try a ZR1600 amp for less than the cost of rolling tubes once!

Contrary to popular belief, the 1.6s don't need nearly as much power as the 3 series maggies. Actually, I found them to sound better with tubes. But you will need a good solid 100-150 watts of tube power, but the coherency and midrange you get will sound much better than an average SS behemoth. My RM-9 did a fine job with 1.6s, but was a total flop on 3.5s.

Oz

Look for a used Spectron Digital One. 500 wpc into the Maggies; it really opened my speakers up and tightened the bass on my pair. Class D switching amp...tiny and the idle current is only 20 watts, so you can leave it continuously on without juicing up your electricity bill.

Think of it this way: all cars will do 70 MPH, but some get there MUCH more quickly! It's not just a question of "loudness" [SPL] but the "opening up", or just darn sounding better...the 1.6's require a lot of power to "open up".

Maggies are easy to drive up to the 'knee' of their magnet system which is not push-pull (MG 20.1s are an exception and are easy to drive at any volume). Getting additional volume above the knee requires a lot of power as the speaker dynamically compresses. This has to do with the distance that the diaphragm gets from the magnets during excursion- the strength of the magnet decreases by the square of the distance. Getting bass off of the diaphragm helps a lot too as that effectively limits excursion, allowing 'below the knee' operation as some fairly high sound pressures.

Below the knee, they are easy. A set of our M-60s will do quite well if used with a set of ZEROs. The trick with using any tube amp is an effective 3-4 ohm capability, which is a stretch for many tube amps. A set of ZEROs solves that nicely.

Atmasphere...With a one-sided magnet, the field would get stronger in one direction and weaker in the other. I would therefore expect the speaker efficiency to change little with increased excursion, but with distortion increasing.
Do you have any solid info regarding the field spatial distribution? The diaphragm excurion is so small that I question how much field variation actually exists (as opposed to theory). I have always believed that getting the very low frequencies out of the woofer is helpful for cone drivers, but you point out that for Maggies it may be even more important.