I find that Audio research Preamps are a little leaner than CJ's but still provide great detail soundstage etc. CJ Tube amps are lush. I combined and ARC SP16 with CJ Premier 12's and for me this is a perfect match, with my Aerial LR5's which were a little forward.Depending on your listening habits and equiptment Preamp tubes can last 3-5 years and Power amp tubes up to 2-3 years or so