In spite of the bad reputation that Knob Tension drums have, they actually can sound really good. I used a Knob Tension set on a few rock gigs and they were fantastic. The bass drum and toms had a very warm, rich tone and were easily tunable and playable. Lots of punch from the bass drum. However, the snare drums are not capable of higher tuning due to the design of the interior workings. If the heads are tightened too much, the reinforcing rings can break loose from the shell. Jack Lawton came up with a solution to that problem. By installing wooden dowel rods straight through the shell and anchored to the reinforcing rings, the re-rings won't break loose. The metal hoops hid the dowels, so cosmetically the drum looked great.
Moral of the story: Don't believe all the negative hype about Knob Tension drums. In the right situations, they are incredibly cool looking and sounding drums. But I also like Edsels, so what can I say?