You are right that there's no space for a quieter fan *in* the KPA100. Indeed I suspect it was the on-going comments about the noisy little beast that cause a lot of thought about "whisper-quiet" fans in the K3.
However, there is a way to keep the little beast from turning on except in the most extreme situations: improve the cooling of the heat sink on *top* of the KPA100. Several of us had great success adding a simple muffin fan sitting right on the KPA100 heat sink. Mine was raised just a bit by putting some rubber "feet" on the fan that sat on the heat sink. A large fan is nearly inaudible (I added resistor slow down my 12-volt 4" fan) and keeps the amp much cooler, limiting the need for the "whizzer" in the back to do its thing. Be sure you aren't blocking the air vents at the forward end of the KPA100's fins. Many owners don't realize there are spaces there. Air driven by the small fan flows across the KPA100 inside the K2 and through the holes at the front end of the heat sink fins and so helps cool the heat sink fins too. Be sure your added fan supports that air flow rather than fight it. Ron AC7AC -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Randy Moore Sent: Wednesday, May 13, 2009 9:09 AM To: Elecraft Reflector Subject: [Elecraft] K2: Speaking of fans! Is there a quiet fan upgrade that anyone has tried for the KPA100 (K2)? The original fan is pretty loud on high speed. I have my KPA100 and KAT100 in an EC2, so there's probably space for a different sized fan, if it were quieter. 73, Randy, KS4L ______________________________________________________________ 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

