Forgot to say I will be stealthing 99,9% of time, so AD20, UA5 and PS2 might be too much for a show.
I think I will take a PS2 used, no money for anything else after buying a JB3 and the mics. Will this be enough to get a good signal?
If you have a ps-2 and ad-20, the ua-5 becomes unnecessary. The UA-5 does the following three functions:
1) Phantom Power
2) Preamp
3) Analog to Digital conversion
With the ps-2 and ad-20, you get all of these. The PS-2 supplies phantom power- thats its sole job. The Ad-20 is a preamp that also does analog to digital conversion.
I've stealthed the UA-5 before, but not really in situations where you have to go through any kind of security to get in the venue. If you can get it in the venue in like a bag/manpurse or something, you'll be good. Also keep in mind that with the UA-5 have to carry around somewhat large battery too- whereas the PS-2 and AD-20 can be run off regular 9v batteries.
Also, check the pre/ad section about needing attenuators with the AD-20. It has a +17db of gain added to the signal, even when the knobs are turned all the way down- I've been in situations where I've totally needed attenuators- but those were loud metal shows.
Now, there's the subjective matter of which sounds better (to your ears) - the PS-2/Ad-20 combo vs. UA-5, but thats for you to decide- maybe you can listen to some samples of shows people have done with each rig and decide what you like better.