Vintage amps - Carver, Krell

Can somebody tell me what is the main difference for
Carver TFM, M and silver series and also
Krell KSA, FPB, MDA series?

Which model from Carver and Krell would you look into or consider based on the sound? People tell me to go with one that is the later design, would you agree?
For Carver, I believe the later TFM models are higher current and would work better with speaker designs that are more current hungry and have more difficult loads.

I had an m4.0t Silver Seven prior to my current Musical Fidelity A3CR. That model delivered a lot of watts per dollar but was not high current. It sounded very good with Magnepans for example when I had them but low end was impacted at lower to moderate SPLs driving more current-hungry designs, like the OHM Walsh 5's in my system. When cranked to higher SPLs , it still sounded very good for the money with the OHMs.
The Krell web site used have a chronology of what they considered significant improvements to their products. Perhaps it's still there.
For Krell go to the HIFICRITIC web site and look at the Colloms listings for amplifiers. Martin Colloms has tested just about every one and his ratings are for current sound standard, not at time of original test. Will give you an idea of what someone who has tested and used about all of them thinks.
I had a Carver TFM 24 for about 17 years. It handled every load I threw at it without getting above room temperature. It wasn't the most neutral sounding amp, but definitley loud and powerful. I was looking for a more nuetral sound, it was a bit distorted, that was my only reason for selling.
Stanwal, thanks but the website is hard to find the info you mentioned...

For Carver units, would the TFM be better than the M or PM series?

Would the Onkyo power amps be something better than both of them if we talk about the same output Watts?
For high watts/high current, if you could swing it, I would look at newer Class D amps for best sound and cost effectiveness. Wyred 4 Sound has some relatively low cost units that has attracted attention.

The Musical Fidelity Q#CR in my system cost me $600 used and replaced the Carver m4.0t. It is lower power but high current and should drive most anything in most rooms.

Among Carver amps, I'd swing towards towards the newer TFM units myself with most speakers.