"Roger" wrote in message
...
On Sun, 28 May 2006 13:47:35 GMT, "JC" wrote:

Ahhhh... That is just a pice of Silastic (TM) sheet wide enough and
long enough to form a chimney when wrapped around the tube. I can't
imagine it'd take much engineering. It's a very crude, but effective
design and easy to make if you have the material.



Roger,

I proposed a single rectangular piece to wrap like they do on their 8874
amps. I even gave them dimensions, and a good picture of my 8874 mounted in
the amp. A round continuous piece would also work. So far two business days
have elapsed without a reply from Alpha. I hope to hear from them on
Tuesday. I'll keep you posted.

For my brief tests I used a 10" long X 2" wide X .02" strip of Mylar
wrapped around the tube. It worked fairly well, but got de-formed from the
heat. I later jumpered the fan resistor to speed up the cooling fan. For
some reason the MLA-2500 fan speed relay was not kicking in the high speed
mode when keying the amp. I need to look further into that wiring, and see
what is going on there. There is a button to enable the high speed fan
option, but it does nothing until the thermal Klixon OT-switch clicks on,
and then the fan goes to hi speed.

Jim