Jim is correct, as is Stuart. I, and others, know of properly terminating
an audio input to avoid ground loops and potential RFI. Usually this is
done by the input device(mike, amp etc). In a test situation, a termination
resistor that doesn't draw any current does the same thing.
Ron
K3MIY
Quoting Jim Brown <k9yc@audiosystemsgroup.com>:
> On 2/1/2012 3:07 PM, Stuart Rohre wrote:
> > Be cautious about grounding a non grounded audio output, like a phone
> > jack or spearker output. It may be intentionally floated as a balanced
> > output circuit.
>
> Hang on a minute -- we're not talking about an OUTPUT, we're talking
> about an INPUT. And, NOT bonding ANY cable shield to the chassis is the
> #1 cause of RFI in ALL equipment, including ham gear.
>
> Note that I speak with some authority on this -- I'm Vice-Chair of the
> EMC Working Group of the Audio Engineering Society Standards Committee
> that WROTE the Standard for solving the Pin One Problem, and have
> published considerable research showing that Pin One Problems are the
> primary cause of RFI in almost all gear. That Working Group also
> includes engineers from ABC-TV, the BBC, Dolby Labs, and Lucasfilm.
> Henry Ott, who literally wrote the book on EMC, is also a member of the
> WG. Neil Muncy, ex-W3WJI, who published the first work on the Pin One
> Problem in 1994, and I were both elected Fellows of the AES, partly on
> the basis of that work.
>
> 73, Jim Brown K9YC
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
>
-------------------------------------------------------------------
This mail sent through CSOnline Webmail http://webmail.csonline.net
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|