On Mon, 2 Jun 2014 06:05:22 -0700 (PDT), Harry Yingst via Elecraft wrote: > You could always try replacing the fan with a quieter fan.
I would consider that myself, but only with one recommended by the good people at Elecraft. The fan in the KPA is VERY loud when it hits the last two speeds. Warp and Turbo Warp would wake my wife in the next room if she was a light sleeper, although I virtually never get it up that warm. It was just my short excursion on 6M FM that really got it up there fast. My issue isn't with the fan operation, although I wish it would come on just a bit earlier than it does. My issue is with the sound level out of this particular fan. It's a screaming banshee when it gets up there at speed. It's a very "raw" sound, not the sound of air moving, but of a high speed motor. My only hesitation with putting a different fan in it would be compatibility with the speed control circuitry. I just won't do it, especially under warranty, without Elecraft's recommendation and blessing. They've got a good product and I want to keep it that way. Typing this up raised my curiosity and I went to the shack and ran a control test into my Bird load. I set my rig at 10W on 52.525 FM, which gives me 200W output. With manual fan control, I made sure the amp was cooled to 33C as a starting point, and then set the fan back to NORmal setting. I keyed the rig on FM at the (unmeasured) 10W setting, and sat back to see what it did. It took 75 seconds to reach 70C. At which point, the fan is at 5, a rather noisy speed. It seemed to level out at 77-78C for a bit and then went to 80C at 4:50 minutes. I ended the test at that point. At 80, the fan went to 6, the highest speed, screaming away. With this test, I'm confident that it would probably handle anything I would ever do to it in normal operation, especially given the fact that I'm not dumb enough to do that test at 500W output. :o) I think the fan does a pretty good job, but do wish it was quieter. I never hit those higher speeds, except in test conditions like this. My normal use has it hitting 70C only on the rarest of occasions. Gary -- http://ag0n.net 3055: http://ag0n.net/irlp/3055 NodeOp Help Page: http://ag0n.net/irlp ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
