I've been stuck with solid state amps for years. I was about to upgrade to a JCM 900 last year, but ended up missing out at the last minute. (The joys of craigslist). I've sorted through countless models, but can never test them all side by side. I'm curious as to what the best quality used tube head for around $300-$400 USD would be. My only concern is that I want something definitively tube, no hybrids. Also, while I'm not expecting a miracle for that amount, I need decent tone.