A resource for All Things Tube/Valve related

[rnolan]

Ok so I made the preamp and poweramp boards child boards of this one (go El).  So at this level we can talk tubes in general (remembering tubes are VERY subjective so all opinions are valid).
I've attached a tube article which I found quite interesting/edifying, it's posted elsewhere on the depot but probably belongs here.
As I come across related posts, I'll copy them into this area to try to make it a good tube information resource.  You can talk anything about tubes here, but primarily it's about what works in ADA gear. So what works for you and why ?