Pass First Watt models ... confused


I'm curious about the First Watt products. I'm a very happy owner of a Pass x250.5 AB amp but interested in experiencing full class A. No plans to sell my less than 1 year old x250.5, and I'm not rich so I won't be sinking cash into the exorbitant prices of a new XA series. A used Aleph is a possibility, but those are getting fairly old and I wonder about maintenance issues.

Therefore I am looking at the reasonably-priced First Watt line from Nelson. But I'm quite confused by all the different models. Can anyone help clarify this puzzle for me? Thanks.
abrew19
So....What are the acceptable parameters for speaker sensitivity for these amps?
Al has it right; most of these are special purpose amplifiers, and you would be wise to carefully read the manual for each before purchasing.

Also, if you call Mark at Reno Hi-Fi, he can help point you to a suitable model for your setup, if one is appropriate.
Danielk141,
"I also owned the Aleph J2. It sounded good."

Did you mean the Aleph J or the First Watt J2?
I've got the J2 mated to some Gallo Strada2s (90db efficiency). I absolutely love the amp. It's very much a SET-like sound with good bass and is completely quiet. I've had some very expensive SET amps and prefer the J2 to all of them. Assuming your room isn't incredibly large, 25 watts should be plenty.