Guy, Thanks for not ignoring my problem any more and lending a hand :-)
Answers to your 1) 2) 3) 4) questions below... On Jan 13, 2012, at 11:09 AM, Guy Olinger K2AV wrote: > I've been ignoring this thread, but your last post piqued my interest. > > Several questions require answers before I can go on. Just note that while > we tend to concentrate on the last new thing, the "workbench" and instruments > and their connections have far too often been the entire problem. You would > CERTAINLY NOT be the first, nor the last, to suffer from this as some issues > are ghastly subtle. > > 1) What frequency is the hum. Well, I am not good at guessing the frequency but it does sound like AC power type hum, maybe a little higher but I am just guessing. > 2) By what means are you detecting the hum? Speaker? Line out to spectral > audio program or some such on the Macbook? Other means? Other means, > describe the method and connections in boring detail. It is critically > important to precisely understand the means of measurement. Hum is detected in all (I repeat ALL) audio outputs. These include my West Mountain COMspkr, and it includes the internal K3 speaker when the COMspkr is unplugged, and it includes my Yamaha CM500 headphones. It does not include my Macbook though -- I do not use my computers with the computer in any fashion (no DATA, no Audio, no speaker use, no application programs except for the K3, P3, and KPA500 utility programs). > 3) If detecting the hum on the Macbook, what level is the hum? Not detected on Macbook -- Macbook is 8 feet away and not connected to rigs in any way. > 4) If detecting the hum on the Macbook, describe the connection between the > K3 and the Macbook in boring detail. See above. > > 73, Guy. > > On Fri, Jan 13, 2012 at 1:30 PM, Phil Hystad <phys...@mac.com> wrote: > As noted in a previous post, I disconnected EVERYTHING. Nothing on the back > panel of the K3 at all except for a Li-nano-phosphate battery as my power > source. All AC off at the breaker panel for this room. The only electrical > equipment on was my K3 via the battery and my Macbook Pro laptop via its > battery. > > Given those conditions, the hum was still there. > > Jim Brown suggested that I consider TXEQ to cut off the low frequencies, I > did max cut for all frequencies up to 400 Hz. The hum did not start being > attenuated until 400 Hz cut. But, max cut on 400 Hz did not attenuate it > completely. I did not do higher frequencies. > > So, anyone who might help -- where does this hum or buzz come from if nothing > is connected to the K3 and there is no AC flowing anywhere in the room. It > is 28 degrees outside, which is freezing cold plus for the northwest and I am > not used to that but my next step is to go outside and check my grounding to > ground points. > > phil > > > > On Jan 13, 2012, at 10:03 AM, Geoffrey Mackenzie-Kennedy wrote: > > > When the KPA500 is in standby, I assume that its AC mains is still > > connected. Have you tried pulling the KPA500's mains plug to narrow > > the search? > > > > Is your P3 sitting between the KPA500 and the K3? > > > > 73, > > Geoff > > LX2AO > > > > On January 13, 2012, at 18:20 +0100, "Phil Hystad" <phys...@mac.com> wrote: > > > > <snip> > > > >> If I lay my hand on the top of the K3 the hum disappears. If I lay my > >> hand on the P3 sitting next to K3 the hum disappears but not as much. And, > >> I can do the same with other grounded equipment. I have checked my > >> grounds and they all seem to be pretty good. > > > > and earlier > > > >>> So, I am thinking maybe it has > >>> something to do with the KPA500. So, I put that in Standby and the hum is > >>> still there on the audio. The mic is the MH2 hand mic plugged into the > >>> front of the K3. > > > > ______________________________________________________________ > 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 > ______________________________________________________________ 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
