DIY Power Attenuators?

[RyCLB]

Hey guys. I'm looking for some info on a DIY power attenuator (a la Marshall Power Brake, Hot Plate, etc, etc). I found some info here (http://www.amptone.com/g243.htm) but I'm wondering if there's more to a project like this. Could it really be as simple as putting a 4, 8, or 16 ohm, 50 watt resistor between the output of an amp and the cabinet?

Any and all help would be greatly appreciated! :D

[RoboPimp]

weber makes a kit. go to their website and check it out: http://www.tedweber.com