I'm picking up an Ampeg V4BH from a local seller this weekend. If it all goes down as expected it should sit nicely atop my SVT-410 HE. Asking price is $650 firm, mint, perfect working condition. Not sure on the year. Made in USA by SLM Since I've never owned an all tube head before, I need some help on what to check out before putting my $$ on the table. Thanks in advance.