Happy to report that the subwoofer problem got about 95% better with the
placement of ferrites immediately before the subwoofer on the power cord,
the LFE channel and the speaker channels. It still picks up just a tiny
bit of 20m racket even with nothing connected to it, which I suspect could
be a
On 5/23/2020 5:01 PM, Nicklas Johnson wrote:
Sadly, it seems like most consumer-grade audio equipment is optimized more
for cost than for design quality and RFI suppression, even equipment that's
supposed to be "high-end." And then sometimes you can buy a piece of cheap
gear and it rejects RF be
I certainly agree. And of course there's no "one size fits all" for RFI
problems. I think it's somewhat likely I have multiple problems going on
here too; I noticed, for example, that even when it's completely
disconnected from all its audio inputs, I can still hear a little racket on
the sub; it
All of Jim's material is like gold for RFI suppression.
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 2:02 PM, Nicklas Johnson wrote:
Thanks, Dave. A very good point about the a
Thanks, Dave. A very good point about the amp picking up stray RF off the
cable and returning it as audio; I'll be sure to clamp down on both ends.
It's definitely not a new problem, and I've used Jim's recommendations to
much success in the past. In fact, I referenced it again today because I
c
On 5/23/2020 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
I would put the ferrite material as close to the speaker as possible,
and as close as possible to the amp...
It is important you also protect the amp from stray RF. If the speaker
cable is picking up RF, and feeding it back into the audio amp output
stage, you can get rectification within tha
I know you already ran the cables, but twisted pair would probably help.
wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)
> On May 23, 2020, at 9:37 AM, Nicklas Johnson wrote:
>
> The backstory as briefly as I can make it: I wanted to place my home
> theater subwoo
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-->iso
there's just the two
of us in the house.
- pjd
-Original Message-
From: elecraft-boun...@mailman.qth.net On
Behalf Of Nicklas Johnson
Sent: Saturday, May 23, 2020 12:38 PM
To: elecraft
Subject: [Elecraft] ferrites for subwoofer: before or after isolation
transformers?
The backstory
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
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
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