It is a good idea to purchase a vintage tube pre-amp.

Since the new one are pretty expensive and what I can afford is an old one with budget of US$2000~3000. Since I don't have much knowlege on electronics, but I have authentic listening capabilities. Is it good idea to buy an old gear of tube pre amp. around 10 or 15 years such as Audio Research SP-15 or something similar (the newer one within my budget is better of course).  I would prefer a stable, long time use gear without much trouble.
The classic SP-15 is a classic ARC pre & cherry ripe for high end mods imho. Bare is mind, it is quite old, so unless you find one already refurbed unit, I would look for a stock example in good nic & save up for a refurb incl: higher end caps, some nice WBT rca jacks, Furutech IEC & some nice matched NOS tubes. The only caveat is you’ll need single ended cables. Also, the included phono stage is ok, but i’d look for something like a 2nd hand ARC PH3 SE if you want a decent matching phono stage.
For $3000, a PH-3se phono stage and an LS-16 line stage might be better than an SP-15, don't ya think?
@bdp24, Sure. But the SP15 would be fun to go all out modding ;) The look and vintage of the two components would match up nicely too.
True. I love the look of matching faceplates, especially ARC's and McIntosh.
Tks for your kind opinion, in order to prevent troubles, I am trying to avoid too old models. But as you know, the new models are quite expensive and one of my friend also gives the new models bad review in sound reproduction.  Such as R3, the dealer tells me that when the LED is in trouble, there is no parts for replacement........