Cooling fans for tube amp

Thanks Bmcleod, I'll check them out.

Thanks guys. I did check out a RS fan that was recommended by other users and I should be able to install w/o too much effort.

My biggest question that Undertow answered was the push or pull issue and he obviously said to pull the air out of the cabinet instead of pushing it back over the amp.

I could get really involved and install a thermostat so it only comes on when it gets too hot and then shuts off after cooling down, but for now I think I'll just go with the pre-amp switch and let it run when the system is under power regardless.

Bmcleod or Russe41, would you run two 24v DC fans in series causing them to then run at 12v? or how would that work?

I will have three shelves in the cabinet with the amp on the bottom. What would be the best positioning for two fans? Originally I was thinking of one fan pulling air out of the back just behind the amp since that's the big heater. Not sure I could get circulation from top to bottom because of the shelves blocking air flow.

Possibly two fans pulling from the back- one high one low?

Well I just got the cabinet and set the equipment up. Everything is working great, but yes the underside of the shelf directly above the amp is hot as a skillet. Still thinking of getting some automotive heat tape for the underside of the shelf just to protect it and get the RS 4" fan to pull the air out of the lower part of the cabinet.

I had them drill three 3" holes spaced equally from top to bottom. I'm running cords/wires out of the top two and left the bottom one unused for the fan.

For now I think I'll plug the fan to the switched power strip I set up off the pre-amp so it will run as long as everything else is under power.

My plan is to get the 4" fan and mount on the back side of the cabinet. The cabinet does not have doors. There is a 3" circular hole perfectly situated in the 3" space above the top of the amp and the next shelf.

The fan should pull ambient air from the front of the cabinet across the top of the amp and out the back. I will also look into a reostat so I can modulate the air flow.

The amp needs to be on the bottom for low CG and overall stability. I also intend to get some heat tape to attach to the bottom of the immediate shelf above the amp. My Akai tape player is situated directly above. I don't believe I'll run into an issue with overheating the other componets, but do want to keep the amp at a reasonable temp.

So I just completed the install and the fan is just too freaking noisey! It hums along at something like 3100 rpms and you just can't stand it for more than 30 seconds. I powered it up prior by itself and it seemed fine but once installed in the cabinet you can hear it in the next room.

The electronics store person where I got some of the wiring and a little protectant grill talked me out of the reostat because he said it would be hit and miss to get the values right and may not adjust properly. But I can't leave it running full tilt all the time so I'm either going to toggle it for on/off sessions or find a reostat that works.

Geez, why isn't anything simple....

Thanks Newbee. I will go for the rheostat to get the RPMs down and I like the rubber pad idea. Is that something also availible at HD?

Thanks to both the latest posters. Yes, I do need to get the fan speed down and will look for a rheostat today. 3200 rpms is just too much. As I mentioned above, the fan seemed pretty quiet when I powered it up loose on a table- even at full speed.

Will also get some rubber grommets. I did slightly over size the holes so there is some movement around the long screws. Will probably need longer ones now that I'll add 2 more grommets to each side of the attachment.

If it's still too noisy I'll look for a better fan. This one is off the shelf from RS but appears to be well built. It is a ball bearing style so we'll see if I can get the noise down.

So here's the latest if anybody is still following.

Got a 25 watt rheostat per local electonic store recommendation. Hooked it up wrong initially and then got it right. Installed it in the back of the cabinet. My cabinet is 36" high and is on casters so I can easily move it around on the carpet. Believe me this was smart considering how many times I've already had to move it back and forth to get my set-up right.

Everything is powered off the pre-amp via power strip w/surge protection. Pre is also fused. Just finished a 90 minute listening session at fairly good volume so the amp got to full temp. Fan was set at about 50% so I assume around 1500 rpm, maybe less. Fan sound was negligible with music playing and a bit less than the normal amp hum with ambient room sound( which is pretty quiet here).

So bottom line is the fan kept the amp and other electronics at a very reasonable temp running at about half speed. For good measure I set the fan at full speed for 5 minutes after my session and then shut everything down.

I know there are quieter fans availible but so far I'm happy with the set-up. Oh yeah, and I did install some rubber grommets on the attaching screws between the fan housing on the outside of the cabinet and the wood backing. Not sure how much this helped but it seemed like a good idea regardless.

Thanks again for everyone's input and comments. I hope this also helped someone else out with their own cooling issues.