I've got a set of these on the way, as well as a handful of their next two smaller siblings, just because I like to have a variety in my desk for various applications: https://www.fair-rite.com/product/round-cable-snap-its-2631181381/
Given the arrangement at the subwoofer of wall-connection-->isolation transformers-->subwoofer, would you put the ferrite right before the subwoofer then? I didn't think about adding one at the amp; though I haven't had problems with any common mode noise getting into the amp from the other speakers in the room, I can't be sure about the LFE coaxial cable, so that wouldn't hurt. Nick On Sat, 23 May 2020 at 10:08, Dave Cole <[email protected]> wrote: > Grab some FT-240/31 ferrites from Fair-Rite, (these are the large > rings), and put seven or eight turns of speaker cable through each, > tight wound. Add one at the speaker, and one at the amp. > > 73, and thanks, > Dave (NK7Z) > https://www.nk7z.net > ARRL Volunteer Examiner > ARRL Technical Specialist > ARRL Asst. Director, NW Division, Technical Resources > > On 5/23/20 9:37 AM, Nicklas Johnson wrote: > > The backstory as briefly as I can make it: I wanted to place my home > > theater subwoofer in the corner of our living room; doing so required > > running two speaker wires and a coaxial cable under the house and > plugging > > the subwoofer into a different outlet than the AV receiver; this in turn > > resulted in ground-loop hum (because of a tiny difference in potential > > between the two outlets) which I worked around with a set of 1:1 > > low-frequency audio isolation transformers. The subwoofer is of a type > > that produces a signal based not only on the LFE channel, but also on the > > left and right speaker channels, thus the two speaker wires along with > the > > coaxial cable. > > > > Now the subwoofer is picking up common mode noise on 20m, which isn't > > terribly surprising, as this happens a good bit with consumer-grade > > electronics. I'm hoping to mitigate this with some substantial ferrite > > clamps for all three connections and as many turns as I can get through > > them. > > > > My hunch is that the best place in the path to clamp them on will be > > immediately before the connection to the speaker itself, on the speaker > > side of the isolation transformer, but I wanted to get the opinions of > > folks who have solved this problem in the past to see if there's any > reason > > the ferrites should come before the isolation transformers. > > > > Thoughts? > > > > Nick > > > ______________________________________________________________ > 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] > -- *N6OL* Saying something doesn't make it true. Belief in something doesn't make it real. And if you have to lie to support a position, that position is not worth supporting. ______________________________________________________________ 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]
