Need at least 900wpc in 4ohm


Suggestions for what can do the job? Thanks.
tccaux
Sunfire 600 should be on the top of your list. It pumps out 1200 watts into 4 ohms and sounds fabulous at all volumes. It's a shame they aren't made anymore, but they come up on ebay regularly.
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.
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.