Preamp recommendations for under $600.00

I have 3 modded PAS 3 which I use with SS amps, as good as most 1500-2k units.
IMO best is Bottlehead Foreplay which sounds about as good as anything except in last octave of bass, which is still OK.

However, neither seem to show up here much lately .

I've owned 3 of the four and seen inside the Jolida,PAS 3 and Bottlehead are easy to fix, odds are great you will end up throwing the others away because they will surely need re-capping etc and you won't like the price , assuming you even find some one to do it.