The tubes in my "original series" Freya aren’t especially hotter than they should be (4 preamp tubes should seemingly be hottish, but...meh...), and note that the top vents are around the tubes...there’s plenty of side venting making for good air flow, and I think the 2 transformers are simply close to the lid so it’s relatively toasty above them but not excessively so. I give tube gear plenty of air space and it hasn’t melted yet, a good sign. I think people bought tube risers mostly to not fatigue the stock tube sockets with excessive-compulsive tube rolling, but mine have been fine and hey...I roll tubes man...uh huh...I use a Dennis Had 12wpc single ended tube amp and the Freya has plenty of output to drive the thing, especially the tube gain that I always use except when utilizing the passive or FET setting to keep the tubes honest, a cool instant gratification feature. High efficiency Klipsch Heresy IIIs make it all work swimmingly.