I love a lot of the old vintage stuff too, but here are 3 things that would stop me from buying them. 1) Much of the old gear doesn't sound good by today's standards; 2) Much of the stuff you can buy wasn't well taken care of and is only suitable for a "scratch and dent" sale; 3) After 25 years or so the capacitors will have dried out. Many of the ICs and transistors are no longer made so can't be replaced. It could cost you hundreds of dollars to get the stuff repaired if you can find a good tech. Good ones are a dying breed.
I bought an older Adcom amp a few years back and a few of the output transistors went - no longer made. Now, it's an expensive boat anchor.