[Amps] Wind! In series or parallel?

[Bill Turner]

ORIGINAL MESSAGE:

At 07:28 PM 8/24/2006, Martin Sole wrote:

>Tube specs for 1 tube state 9cfm as an example.
>
>2 tubes operating together need 18cfm, right? or still only 9 total? Or
>different again?
>
>If I'm measuring airflow what is the relationship between total air and
>individual tube air?

------------ REPLY FOLLOWS ------------

Each tube needs 9 cfm, or 18 total. You can not put airflow in 
"series" because the exhaust air from tube A will be hot already and 
will not cool tube B. Both tubes must receive 9 cfm of room temperature air.

Also, the figure of 9 cfm is only a starting point. The real measure 
of cooling power is the temperature of the tube seals as specified by 
the manufacturer. Use either a "laser" thermometer or color-changing 
paint/crayon to determine the seal temperature under full load and 
then adjust the airflow as needed.

I also monitor the temperature of the exhaust air just to be sure the 
fan does not lose power over time. On my amp, the max temperature 
reached is about 195 degrees F. If it goes higher, I know the fan is 
not doing it's job for some reason.

Bill, W6WRT