I built an 18w TMB from the VHT parts clearance at Ubuyguitars. The chassis is meant for a combo. I want to build a head cab for it instead. I have searched, am getting conflicting info. A while back I researched this a bit and believe it to be ok, I have been running the chassis sitting on a cabinet with the tubes horizontal for some time now. No issues. It has the following tubes: 5y3, 12ax7, el84. Looking to confirm this before I start on the cabinet.