Re: cooling an amp (min. Audi content)

[four.rings@mcione.com]

You wrote:

> I've got an amp mounted upside down in my trunk of my 90.  I never
> really had  a problem with it shutting down due to heat until I hooked
> up all 4 channels and now it is 100+ F  in Texas.

Bad idea. I've seen a number of amplifiers with blown output
transistors/IC's due to this very reason. Mount it at least
sideways in order to enable partial cooling by convection.

> I am gonna get a fan for it, question is; would it be better to blow
> air across it, or suck air away from it, like a radiator fan does?

No difference. The cooling effect of the fan is in it's ability
to displace heated air in the immediate bordering layer with the
cool air from the outside. Since voids are not possible, X cm^3
of hot air will be displaced by exactly X cm^3 of cool air
regardless of whether it gets blown or sucked. No frivolous hints
were intended. :-)

The  radiator fan sucks air only if it is situated behind the
grille.
It blows air if it is in front of it. On some (rally) cars there
are both, in the so-called "push-pull"  arrangement.

************************************************************
Igor Kessel
'89 200TQ -- 18psi (TAP)
'98 A4TQ -- nothing to declare
Philadelphia, PA
USA
http://www.geocities.com/MotorCity/Garage/8949/homepage.html
************************************************************