Older PURE CLASS-A Amplifiers


I am looking at some older Pure Class A amps and am curious as to are they as good as some newer amps like the Pass X150, and which ones are recommended, and have they been compared to each other anywhere? Thanks much for the recommendations.

I am considering the following PURE CLASS A amps:
Threshold T-50
Monarchy Audio SM-100 Monos
Monarchy Audio SM-70
Forte Model 4
tpk123
These Clayton aren't too old, but here's any interesting review:

http://iar-80.com/page6.html
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".
There are a lot of Class A tube amps too- any reason they are not on this thread?