Bob, I would recommend you review the forum discussions on this subject last year from September thru November. This was discussed extensively. The K3 APF has been optimized. To reduce the sharp high Q audio sound would entail reducing the Q and flattening out the response. In essence reducing its peaking effectiveness. Yaesu had the best APF to date in their early FT1000D's. They modified the APF to broaden the response and lower the Q to please those that didn't like the sound of high Q audio peaking. This rendered the APF almost useless. They later came out with a mod to restore the APF to its original design. The Elecraft K3 APF is a derivative of this fantastic circuit and Elecraft is quite aware of the Yaesu APF history. Here is a response from Elecraft copied from an earlier discussion on this subject that was nearing its conclusion.
We will not lower the Q of the existing APF function. We might add > > more Q selections -- someday. But we're not going to rush into further > > changes. Our priority right now is to correct some issues (mostly with > > SSB) and do a new beta release at the end of the week that includes APF. > > > > 73, > > Wayne > > N6KR > > There has been many glowing reports on the APF here in the forum. For me it is absolutely super to use now. It has added a new level to my 160 DXing. I am now able to copy and ambitiously seek new ones on 160 which were down in the noise and unreadable before. 73, Bob K6UJ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html