2. amps-preamps
  3. 1170013775

Cooling fans for tube amp

Just read a thread from 2005 about rack cooling fans. I'm having a custom built wood cabinet made with casters for my stack that includes an Audio Research D-90 that can get very warm after an hour or so.

Any new recommendations on what fan to use and how to set-up? Most computer fans don't have standard wall plug connectors.

I was thinking about a 4" diameter fan that will plug into my "Switched" power output off the SP-12 pre amp so it goes on auto whenever I power up. Should it "push" or "pull" the air? Mount on the back of the cabinet with a cut-out for airflow?

I may just run a power strip off the pre-amp's switched output to power one to two fans plus the subwoofer so they all only run when I power up the pre-amp and amp.

Also thinking of putting heat resistant tape/insulation on the underside of the wooden shelf directly above the amp.

Sound OK?

Or something better work w/o a major engineering project?
jamesk58

Showing 3 responses by newbee

newbee
4,815 posts
 
Ahall, FWIW on a 110v fan you can probably add a rheostat and reduce the speed of the fan to a point where you will not hear it at all and you will also minimize any vibrations it would transmit (at full speed) into the cabinet. At least these were problems I experienced and that is how I solved them. FWIW.
newbee
4,815 posts
 
Jamesk58, a couple of observations. 1) If you're cooling a cabinet with tubes you do not need or necessarily want direct air directly over the tubes and 2) don't move any more air than you need to to keep the cabinet interior at room temp.

If your cabinet has openings on the bottom, and top(where your fan should be), you will be surprised about how little air you must, and can, move by one exhaust fan to maintain room temps in the cabinet, even if you should keep doors closed. Thats why I recommended 110v w/rheostat. Use a thermometer to measure air temp and adjust the speed up and down 'til you have it at room temp. Easy to do. Keep it simple as possible. :-)
newbee
4,815 posts
 
FWIW, I bought a fan rheostat for a fan at Home Depot and hardwired it to the fan on a long enuf cord so the control was easily assessable to use and it works fine. What is causing all of the noise it the vibrations and its very hard to eliminate these without reducing the RPM's substantially. You can reduce the effect of the residual vibrations by the way you attach the fan to the cabinet. What I did was to glue some heavy medium soft pad of rubber on to the cabinet surface and then glued the fan to the rubber. You can't just screw something on using rubber as a gasket. The vibrations will pass right thru the screws to the cabinet. Between the rubber isolation and the rheostat you should get the fan down to inaudible.
More to discover