{"id":88,"date":"2013-04-10T11:26:07","date_gmt":"2013-04-10T11:26:07","guid":{"rendered":"http:\/\/www.audioemc.co.uk\/?page_id=88"},"modified":"2013-04-10T11:26:20","modified_gmt":"2013-04-10T11:26:20","slug":"connecting-a-capacitor-between-xlr-pin-1-and-chassis-to-remove-a-ground-loop","status":"publish","type":"page","link":"http:\/\/www.audioemc.co.uk\/?page_id=88","title":{"rendered":"Connecting a capacitor between XLR pin 1 and chassis to remove a ground loop"},"content":{"rendered":"<p>My experience with EMC immunity is such that I never (now) think about trying to removing a ground loop by connecting a capacitor between XLR pin 1 &amp; chassis. The problem is that the inductance of the leads, either side of the actual capacitor element, tends to be too large at frequencies above 10kHz, to be an effective solution*. Thus, the technique only ever removes the low frequency part of the ground loop, leaving the high frequency part (still containing much RFI), in tact.<\/p>\n<p>After 15 years of designing audio systems with EMC techniques, I now realize that ground loops are (mostly) good, and the best way to reduce RFI, is to design the product using the advantages of ground loops &#8211; ie. knowing where they are!<\/p>\n<p>Put simply: the best way to achieve good immunity, is stop RFI from being injected into the active circuit\u00a0<i>common<\/i>\u00a0conductor (inaccurately called &#8220;ground&#8221;). This is because, once RFI has entered the active circuit, the electronics\u00a0<b>will<\/b>\u00a0demodulate the interference, and we will hear this as an audible noise at the output of the circuit.<\/p>\n<p>* = it\u00a0<b>is<\/b>\u00a0possible to minimize the capacitor lead inductance by using an\u00a0annular\u00a0feed-through type of capacitor, but this is rather more expensive and still less effective compared to simply bonding XLR pin 1 to the chassis (see my 2002 paper on the subject).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>My experience with EMC immunity is such that I never (now) think about trying to removing a ground loop by connecting a capacitor between XLR pin 1 &amp; chassis. The problem is that the inductance of the leads, either side of the actual capacitor element, tends to be too large at frequencies above 10kHz, to [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=\/wp\/v2\/pages\/88"}],"collection":[{"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=88"}],"version-history":[{"count":3,"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=\/wp\/v2\/pages\/88\/revisions"}],"predecessor-version":[{"id":91,"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=\/wp\/v2\/pages\/88\/revisions\/91"}],"up":[{"embeddable":true,"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=\/wp\/v2\/pages\/2"}],"wp:attachment":[{"href":"http:\/\/www.audioemc.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=88"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}