Just my take:
Though my response was how to obtain the sound signature in general; the OP already owns a CJ PF-1, loaded with wire-wound resistors and metalized plastic film capacitors, as is your SP11 (NOT a, "vintage" (though an excellent), piece of equipment).
The presentation they’re looking for can easily be attained; through a few simple, internal mods, or possibly: valve changes.
No further equipment purchase necessary.
I agree: there are numerous older components, well worthy of resurrection and updating. I've done a lot of that, over the decades, though typically: to obtain less coloration.
Again: up the to owner/customer's tastes.
"My point, is why buy a new preamp/design when you’re looking for older sound?"

