[Amps] Centurion cooling improvement ideas for AM service

[Will Matney]

Ed,
Generally, the tube spec sheets have ratings for both ICAS and CCS, 
where CCS is what you want for this or close (100% AM Service). If the 
tube is ran CCS at the tube manufacturers ratings it should last because 
CCS is a 100% duty cycle. The only thing that would hamper it is the 
transformer being too small and the cooling the amp manufacturer 
supplied. If the air flow is within the CCS rating of the tube(s), that 
only leaves the transformer. Generally, most amps are designed around 
ICAS for a 50% duty cycle using an AM carrier (Some are less!). SSB, is 
way less than AM so it should raise the rating up to about a 75% duty 
cycle or so I would think. A 10 minute broadcast isn't what I would call 
CCS by any means, so in my opinion, it should work. You may want to 
check the cooling though. The only thing that would hamper the amp 
manufacturer from giving a rating would be that they are not sure about 
their transformers rating! I would hope that they're not just ordering 
transformers without them actually determining the amp and volt ratings 
themselves. With 10 minutes of broadcast, generally a 10 minute rest 
afterward is required too (50%). This changes of course when going 
toward 100% duty cycle.

Will Matney

From: Ed Briggs

"They responded " In theory 450 watts should be safe for key down operation but we could not guarantee the tubes would survive this operation."