I just picked up one of these JCA 20's ( a used one from 2010).
This amp is the balls. Got a great Marshall type tone very similar to my JCM800.
Got it used for 169.00 USA dollars. got 3 12AX7's and 2 EL84's.
 
What im wondering about is Mod's. Anyone know a good place to get any specs on these mods ?
And are you using a JCA 20 yourself ?
 

https://www.facebook.com/groups/104936312880708/

This is a great mod: http://toboy-diy.blogspot.co.uk/2013/10/jet-city-jca22h-depth-mod.html
 

Also, Quick & easy mod to tame down the high end fizz in the JCA20H and 22H: The problem is in the OUTPUT section, not the preamp section as everyone thinks. If your only complaint is the fizzy sound and the tone and gain are fine for you, try this...
Solder a 330 pF capacitor across the 47K negative feedback resistor (R12).

Gustabo,
Thanks a lot man. Sorry I didn't get back to you earlier. I have been tearing it up with this amp. I love it !!!
As I mentioned in my first post, it has a nice grit and it is some what close to a JCM800. not exact, but deff some of the same overtones, harmonic distortion.
 
I own quite a few Marshalls myself, I have a really cool collection of 1980's Marshall solid state amps as well
(like the 5210, Lead 12 mini stack, lead 12 combo, bass 20, master lead 30).
 
These JCA20's are cool little amps, like you mentioned though, need to tame the ice pick/fizz.
Im sure using a Vintage 30 isn't helping either :-)
When I use my Celestion G12 Greenback the fizz is much easier on the ears.