The "Quiet Mesa Walkabout" project...

I posted this in the Mesa Walkabout Mega(?)thread, but it's kinda' buried there, so here it is for others...

Ok, so the AcoustiFan AFG80 fan gasket and washer kit was a wash, because I didn't want to change the orientation of the fan by moving it up against the back panel (away from the output components).

Instead, what I did is cut some small grommits in half (to essentially make them thick rubber washers) and sandwiched the back panel between them. In other words, grommit, back panel, grommit, standoff, fan, and the screw passes through it all.

The idea is to try and isolate fan vibration from transmitting to the case, making it louder.

To be honest, with this fan, the vibration is so minimal I'm not sure this step has any real benefit, but it couldn't hurt, so I went ahead with it.

Here's a back view so you can see the screws up against the grommit halves.



Conventiently, the screws threaded nicely right into the fan, so I didn't even need to put the original lock nuts back on (which you can sort of see in the background in the second picture below).

Here's an internal view so you sort of see the standoffs holding the fan closer to the components.



The results were quite good. Of course you can still hear the fan, but it's quiet enough now that it's no longer annoying at all. Further, while it doesn't move as much air as the original fan (28CFM vs 36.5), it does seem to move a good amount, so I'm not very concerned about overheating.

Total cost, about $20.00 including shipping for the fan. These fans are kind of expensive (relatively speaking) at about $14 each. Most 80mm case fans are about $5.

http://www.silenx.com/fan_pro_54.asp


I'm going to run with this for a while, but if, under some load conditions, it seems to struggle, or especially if it ever shuts down on me, I'm going to go a different route. Tri-cool. Basically, a switchable fan, so I can run it slow/quiet for home/studio, and fast/loud for gigs (where it wouldn't matter anyway).

In any case, so far so good.

 

I'd imagine it's because they have to cool more than one chip with a heatsink, and the affect on the selling price.

In many amps, you have a bunch of small heat sinks, so each one's dissipation isn't affected as much by others, and/or a HUGE heatsink like in the Walkabout. I'd imagine a $3 fan is a way more attractive option to a cooling system that might add 100's of dollars to the selling price. Plus, in particular with tubes, I don't think it's possible to use anything besides air safely and economically.

 

Welcome back, Tombo! You should have a very special delivery Thursday.

 

DOH! Ok.

 

32CFM, and at the same noise rating (14dBA) as the 28CFM Silenx I used, that seems like a good choice to me.

Again, the original fan is 36.5CFM, but I'm not really sure all that was needed anyway, and I replaced mine with a 28CFM model, and had no problems with it. Admittedly, I didn't push it hard/long on a hot sunny day, but still.

I assume no liability on this, but if it was my amp, I'd go for it.