The frequency of the sidetone makes a *big* difference in the waveform. Also, rather than assume it's as good as it gets, it might be worth taking a close look at the filter circuit provided. The sidetone is filtered by U10B on the Control Board and associated components. If something is amiss there, the filtering might not be as good as it should.
I noticed that Ken K3IU pointed out that there *was* a mod that took place somewhere around S/N 3000 that did clean up the sidetone a bit more. It'd be worth looking into that further if you have a pre-S/N3000 K2. I believe that involved adding a 47k resistor between C24 and RP7 pin 8, changing electrolytic C33 to 4.7 ufd, and adding a small 47 mHy choke from RP5 pin 7 to ground. Just because some of us aren't so bothered by a little buzz'n and clunk'n doesn't mean that it must be so ;-) Indeed, the grumbling about the K2's sidetone died down so much that I suspect the mods did a very good job. That sounds to me like it's likely something not quite right rather than a design deficiency. Ron AC7AC -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Rob Locher W7GH Sent: Saturday, August 04, 2007 11:59 AM To: Elecraft Discussion List Subject: Re: [Elecraft] Sidetone with harmonics at 400 Hz... Hi Ken, Thanks for the email. I've compared the sidetone from my K2 to the sidetone from several others, and mine is about typical. I don't doubt that my tone would look sinusoidal on a scope, since the harmonics are probably several dB down from the fundamental tone. However, they are there, they can be seen on Spectrogram, and they are annoying (to me at least, but not to Ron AC7AC). I also have a problem zero-beating with the stock tone, like Steve N6VL. The bottom line is that the audio from the SCAF-1 is much nicer, and I think that many other K2 users would think so also. 73! - Rob W7GH _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
