I saw a few people selling this amp on here. That amp is massive. It came out in like 78 and weighs 130 pounds. The transformers in there are huge. Here's a pic of the inside. http://www.thevintageknob.org/rotel-RB-5000.html
I looked up the amp online. It came out in 1976 and its list price was 2700$ WOW! that was alot of money back then. The amp looks really impressive. The only thing i would ad is, make sure you can get the replacement parts.