Older PURE CLASS-A Amplifiers

The Levinson ML3 is definitely not a Class amp.
It's a AB with only enough biascurrent for approx. 6 Watts @ 8 Ohms Class A. The ML2 has 25 - 40 (European model) Watts Class A and consumes 400 Watts at idle.
You can bridge two ML2 monos to get 100 Watts Class @ 8 ohm.
The Krells with forced cooling were not my favorites with their flimsy covers and coolernoise. I had the KMA 200 Mk II and the consumed 2300 Watts just minding their own business.
Krell made real good amplifiers starting with their plateau biasing models (KSA 300 and forth)
Threshold SA/1 is a classic. Nice sound beautiful crafted but lamps for meter-illumination have to be replaced now and then. If you don't need the slamming power of a Krell this would be one of my favorites although I wonder if they are hard enough biased to deliver 160 Watts Class A @ 8 ohms. I turned down the biaspot anyway to thermally distress the amp.
Class A is not an indication of good sound anyway.
In most cases it's a waste of energy.
I had the Krell KSA 100 & the KMA 200 Mk II and found them both musically inferior compared to the Rowlands 7 (series II and IV) and 8T which are Class AB designs.
For power and musicallity I found the Rowlands 7 a real "bargain".

Threshold SA/4e is one of the greatest ever pure class A amps.

There are a lot of Class A tube amps too- any reason they are not on this thread?

Don't think you can get the Threshold SA-1 mono blocks for $1000, I've looked.
SA-3 would do, the Forte #4 is a good amp and you would have enough left over to get it upgraded be Jon Soderbreg.
You could even get 2 Forte #4 and biamp for your price.

Aragon 8008BB.