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
What is your experience of intensive wear that pure Class A designs impose to output transistors? Does Class A amps were at a faster rate than a/AB?, which are the sonic implications of such "wear" in older Class A designs?
The older Threshold S and SA series amps can still hold their own against the newer equipment. I am quite familiar with them and have heard many of them over the years at a local dealer that used to sell Threshold. I currently have the S350e Class A/AB model. As someone else had mentioned, I think I would shy away from the T-50 model because I also have heard that the IGBT ouput devices used by the T series are no longer available. All of the older Threshold amps that I have heard, including my own have delivered a relatively neutral presentation, depending on what other components were also in the chain. IMO they have a similar sound to the Pass X series amps. If you happen to see one of the class A SA series for sale GRAB IT!
Don't forget about the Sugden A21ap, excellent 25wpc pure Class A. They show up here occassionally for well under $1,000.
I own a Threshold T200 and I would not consider selling it. Poweful beyond its 100W/channel rating and still one of the sweetest sounding SS amps I've heard. Put a pair of MIT Oracle Cables on it or Transparent Ultras or Refs and you will stop searching for power Nirvana.