Need at least 900wpc in 4ohm

Make this the third vote for the Sanders Magtech.

It is an extraordinary amplifier with a superior power supply courtesy of its linear voltage regulator.

If more power is needed (and it might be if you are running full range ESL or large planar speakers) then the Sanders Magtech in a mono-bloc format will deliver 2000 watts into 4 ohm. That rating is of course RMS for both channels driven at any audio frequency (20 Hz to 20 KHz) and with a THD level cited in the manual of just 0.01% at any power level below clipping.

I would rather hear the speakers with high quality 100 watts per channel class A monos.

Sounds like what you need is a new pair of speakers.

Devilboy, LOL! The Snells do require a commitment! Size of small refrigerators and 150 lbs a piece! But there's a reason they often make the 10 Best Speakers ever list. Certain cult thing as well. The AIII was headed for production release when Peter Snell dropped dead at age 38 (?) in his shop in 1984. A great talent lost to the art and science of audio. Thanks.

I agree with the Tccaux, Snell AIII was one of the best speakers of its time and still may be.
Friends that had them used big Threshold amps.If they can be found that's the amp for these speakers