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Re: Audio troubleshooting - webcast

Posted: Tue Mar 23, 2021 1:25 pm
by russellhltn
jsorens6 wrote:I finally figured out a workaround yesterday though! I pulled out one of the hearing assist devices and used the the audio off that to plug straight into the Vidiu unit and the sound is 10,000% better with no hum.
Sure sounds like a ground loop. An isolation transformer should have solved it (as long as someone didn't try to tie the grounds together.)

Re: Audio troubleshooting - webcast

Posted: Tue Mar 23, 2021 3:05 pm
by CalS201
russellhltn wrote:
jsorens6 wrote:I finally figured out a workaround yesterday though! I pulled out one of the hearing assist devices and used the the audio off that to plug straight into the Vidiu unit and the sound is 10,000% better with no hum.
Sure sounds like a ground loop. An isolation transformer should have solved it (as long as someone didn't try to tie the grounds together.)
Yup, probably just a ground loop. It happens in many bldgs and has a documented solution in the EmTech AVDH1 commissioning manual (see note #2 in the
attachment) . The EmTech recommended isolation transformer is an RDL TX-10B, but the TX-1A works as well and have an adjustable level control.
https://www.ebay.com/sch/i.html?_from=R ... a&_sacat=0

In 4 bldgs I've had hum issues with, 3 issues were solved with the transformer and the 4th was just a wiring error.