There's a road worn (real road worn, not relic) modern era Blues Deluxe for sale for short money. Very short. $250. Should I grab it? Allegedly has had the tubes replaced but comes with the originals. If it makes any sounds at all, it's worth $250, right? Looks like a no-risk buy to me. BUT, I don't know a lot about tube amps past the basics. Are there things I should check before purchase?