I use a simple light dimmer. Works just fine on a 90CFM, 2" Hg blower. 73 de Walt Kornienko - K2WK -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com Search: http://www.contesting.com/km9p/search.htm