Yes definitely draw the heat away vs, blowing air into any component, tubed or not. A variac will reduce line voltage to slow down & quiet that fan, but don't use an SCR dimmer (even one for motor control) because they're typically electrically noisy. Lutron may be the exception but I've never tried one.
Looking for Silent Fan Cooling f my ARC Tube AMP
I have my ARC tube amp in a corner. I like to stick a fan behind it . The one from radio shack worked great but made a little noise. Any suggestions . Thanks to all !