So I'm confused how tube amp "channels" work. I don't understand why an amp such as a Peavey Valveking which has 3 12ax7's gets so much more distortion than a Fender Deville which also has 3 12ax7's. Especially since the valveking is 100w and the deville is only 60w.

Can someone explain that to me and could you also explain the difference between a clean channel on an amp and a distortion channel? Do more tubes get activated when the dirty channel is hit?

It is the design of the circuit
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
Valveking also has a diode clipping stage that gets turned on by the gain boost button. Regarding the function of the amp I leave that part to someone else.

ESP LTD F-50 + Tonezone
Cort EVL-Z4 + X2N
Cort EVL-K47B

Marshall Valvestate 8100
Randall RG1503
Bugera 333
Peavey Rockmaster preamp

Line6 Pod X3
Yeah. What Robb said. You can't base an amp's perceived amount of distortion based on how many preamp tubes it has. Also, some amps use preamp tubes to drive onboard reverb and FX loops.

The design of the circuit has much more to do with it as Robb said. Besides, Fender typically makes clean amps that perform well in the low - mid gain space because that is their forte.