Well, after installing a cooling fan in my Blues DeVille, I decided that I would like to put a bigger fan in the Twin Reverb so I could cool the whole under-chassis instead of just the power tubes. Here is a few pictures.
1. Since this fan is bigger, it is quite a bit harder to get it
to fit inside the speaker enclosure. I used a 4.72" 12VDC
fan like I used on my Blues DeVille. I used some springs under
tension to suspend the fan in mid-air at the back of the amp in
between the back panels.
2. I used a little eye hook at the point where the springs attach
to the speaker enclosure. These are what are used in picture
frame hanging kits, with a closed loop. It is just screwed into
the speaker enclosure.
I used some "s-hooks" to attach the springs to the fan.
This way it is easily removeable. This is by far the quietest
cooling fan I have installed in any of my amps. There is
virtually no vibration transfered to the cabinet. The springs
were taken from the same non-operative desk lamp that I used to
make the original fan support bracket.
All of the wiring remains the same. I have it running on 9VDC
with a 300mA transformer. It runs slower and is quieter, but
still moves around 70CFM.
If computers get fans, why not guitar amps? They pump out a lot
of heat!