[Elecraft] KPA500 - Advantage of min fan speed?

[Jim Brown]

On 9/29/2019 7:38 PM, Andy Durbin wrote:
> Please share you experience of using min fan speed greater than zero, and any data if you have it.

Lots of experience, but I've never bothered to take data. I used my 
KPA500 (replaced by KPA1500) a lot for WSJT modes on 6M. The KPA500 fan 
gets pretty loud after 15-20 minutes of near constant calling on FT8 or 
MSK144, but it takes a lot longer to get that way if a higher minimum 
speed is set. The KPA1500 works the same way, except that it gets a LOT 
LOUDER at LOT sooner.

Neither amp is noisy enough to be an issue on CW or SSB, even with 
fairly heavy HF contest operation. I used the KPA1500 for the first time 
in a RTTY contest this weekend. I started hearing the fans speed up 
after 10-15 minutes of CQing with not many responses, but they never got 
anywhere near the SCREAMING level they hit with digital on 6M.

The fan noise is tolerable because I do 100% of my CW and SSB operation 
with headphones, and for SSB it's a Yamaha CM500 with an attached boom 
mic. And for serious RTTY contesting, I'm running SO2R, wearing a 
headset with one ear dedicated to each radio to help me keep track of 
what's happening on each radio.

The significance of 6M is that both amps are least efficient there.

73, Jim K9YC