Members dravenzouk Posted February 17, 2007 Members Share Posted February 17, 2007 Up for discussion: the practice of jumping pin #1 to chassis ground - or not - in microphone/XLR cables. Different cable makers have different setups. Some put a little jumper lead from pin 1 to chassis ground and some do not. There is rarely any indication of how a particular cable is set up from the factory - you have to pull the connector apart to find out. Can't do that when buying sight unseen (internet) and lots of music stores freak if you start dismantling items on the shelf. Some users set up their cables with differently on each end - one end with the #1/chassis jump and the other without. As far as equipment/processors/gear goes, there are lots of wildly different schemes as far as where/when/how/if signal ground is connected to chassis ground. Many require major surgery to figure out which method a particular manufacturer used. So....on your cables, which do you prefer? Do you use different setups in different situations? What makes your decision? Do you have a particular make/model of cable that you prefer due to this? What factors are MOST important to you: RF interference/hum/shock hazard/connecting gear/cable length/etc.? aaaaaand......go. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 17, 2007 Members Share Posted February 17, 2007 No, never and never. Microphones are justified in grounding the shell through pin 1 but this is always done inside the microphone. Always. I have yet to find an exception. Direct boxes and battery powered devices are another application where pin 1 provides the shielding through to the chassis, but again, this is accomplished through the devices internal wiring. The chassis of an AC grounded device should not have the chassis tied to pin 1 except as the manufacturer sees fit with respect to the design of his/her product. It's not uncommon to do so at the star ground, and often the audio ground will be decoupled with a 1 to 10 ohm resistor and maybe a high fequency capacitor (for RF grounding purposes). The practice of (mostly though not always cheap Asian) cables connecting pin 1 to the shell is a major source of service problems on DIY installations. Link to comment Share on other sites More sharing options...
Members W. M. Hellinger Posted February 17, 2007 Members Share Posted February 17, 2007 It's my personal belief that this practice of strapping the D ring to pin 1 in an XLR cable is a misguided attempt to comply with EU standards regarding exposed metal chassis being safety grounded on electrical products. It's my understanding that to correctly comply with the standard would be to have a seperate safety ground conductor in the XLR cable for the D ring shell ground. Jumping the shield and D ring might technically be "in compliance" as far as EU codes go, but is misguided IMO from an audio perspective. I truly believe that the manufactures who are producing XLR cables with the D rings strapped to the shield do not know what they're doing... they have no concept of what they're producing or what's wrong with their method of assembly. But, these things seem to get started, somehow, somewhere... and nobody seems to know why, 'cept "that's how everyone else does it". It's also common to see Asian produced microphones with integrated stand mounts that have the XLR connector mounted in the body of the mic upside down... so a standard right angle FXLR connector would stick "up" when plugged into the mic. I believe the Star Trek episode titled "The Squire of Gothoes" or the Movie titled "Me, Myself, and I" offers a lot of insight into much of what we're currently seeing with imported products. Link to comment Share on other sites More sharing options...
Members pro1-54 Posted February 17, 2007 Members Share Posted February 17, 2007 I believe the Star Trek episode titled "The Squire of Gothoes" or the Movie titled "Me, Myself, and I" offers a lot of insight into much of what we're currently seeing with imported products. Good 'ol Trelane Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 17, 2007 Members Share Posted February 17, 2007 Compliance to the EU's LVD's would be accomplished by the safety ground EXCEPT on devices where there is no safety ground. On these devices, if rcak mountable, the chassis would be tied to the rack ground which is the same path as AC safety ground and a strapped cable would potentially cause the same problem. Worse, a ground lift of pin 1 wouldn't accomplish anything. Link to comment Share on other sites More sharing options...
Members Keyrick Posted February 17, 2007 Members Share Posted February 17, 2007 Perhaps the rational for this is the aspect that the metal shell will come into contact with the device before any of the pins in an attempt to "Make" a grounded connection before any other connection is made. I don't know. I don't really have a problem with it as long as it is used for a direct connection to a microphone, even though it is not necessary once it is connected to the mic. For interconnection between AC powered devices, I open them up and cut the lead before it is ever used. You're asking for a ground loop if you don't. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 17, 2007 Members Share Posted February 17, 2007 ALL (real) microphones have the shell bonded to pin 1 internally, so having uncut mic cables invites mix-ups IMO. Link to comment Share on other sites More sharing options...
Members Keyrick Posted February 17, 2007 Members Share Posted February 17, 2007 ALL (real) microphones have the shell bonded to pin 1 internally, so having uncut mic cables invites mix-ups IMO. Very true! Link to comment Share on other sites More sharing options...
Members Dogoth Posted February 17, 2007 Members Share Posted February 17, 2007 I open them up and cut the lead before it is ever used. You're asking for a ground loop if you don't. +1 for this ans..... OOPPS -1 for this ans.... Sorry I'll get it right this time Ground 1 for this answer:D Lets see thats: 1 = Ground2 = + (or really high) (unless your an older Euro company)3 = - (or really low) (unless your an older Euro company)D ring = NO CONNECTION Link to comment Share on other sites More sharing options...
Members The Real MC Posted February 18, 2007 Members Share Posted February 18, 2007 I make all my own mic cables and I never tie the shell to pin one. Never had a problem. Link to comment Share on other sites More sharing options...
Members W. M. Hellinger Posted February 18, 2007 Members Share Posted February 18, 2007 I make all my own mic cables and I never tie the shell to pin one. Never had a problem. The EWI XLR cables will contine to be manufactured, as they have been, without the D ring strapped to pin 1 until I have a better reason to strap the D ring to pin 1 than not. I've researched this some, and it seems like US manufactured XLR cables generally DON'T have the D ring strapped to pin 1. And... I still don't know for-sure why anyone would strap the D ring to pin 1? This has puzzled me for decades. I have stacks of resource books here, and nowhere can I find any reason for the practice... or even any hint of a suggestion to do it. I've never seen a cable recommendation wiring diagram showing it either. I also don't know why women's (and virtually all Asian) garmet zippers are made to zip up with the left hand? and... why most folks seem to tie "granny bows" with their shoe laces, rather than tying "square bows". and... why folks first pour coffee in a cup, then cream, then have to find something to stir it with... rather than pouring the cream first, then the coffee... resulting in no reason to stir it. Link to comment Share on other sites More sharing options...
Members Dogoth Posted February 18, 2007 Members Share Posted February 18, 2007 why folks first pour coffee in a cup, then cream, then have to find something to stir it with... rather than pouring the cream first, then the coffee... resulting in no reason to stir it. I'm a cream first guy all the way. I think I picked up this habit because I needed as efficient a way as possible to get caffien into me in the morning (the coffee stirrer is one too many steps for my poor cafien deprived brain early in the morning) Link to comment Share on other sites More sharing options...
Members milesdf Posted February 18, 2007 Members Share Posted February 18, 2007 I'm a cream first guy all the way. I think I picked up this habit because I needed as efficient a way as possible to get caffien into me in the morning (the coffee stirrer is one too many steps for my poor cafien deprived brain early in the morning) eh dont drink coffee but i see tons of kids mixing drinks with the mixer first. obviously the best way to do this is to pour the good stuff in first, the mixer mixes when you pour it in and plus you know exactly how much alcohol you're drinking. ive smacked many a freshman for this. bitches. back to the original subject: i haven't expirienced many cables that do this but whenever i do i chop out the jumper. on the other hand i've experienced 2 different consoles (1 audio 1 lighting) that have a seperate ground that feeds the D ring on output connectors. I feel like if you have a cable that connects to the connector ground you are going to have a loop here, at least inside the console. Link to comment Share on other sites More sharing options...
Members boomerweps Posted February 18, 2007 Members Share Posted February 18, 2007 Go to the Rane website and read what they say on shell grounded mic cables.In a nut shell, AFAICR, grounding ONE end can be a good thing, normally the sending end of the cable. The receiving gear end should NOT be grounded. Chassis to chassis grounding via pin one to sheel can cause a lot of hum problems. Boomerweps Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 18, 2007 Members Share Posted February 18, 2007 It really depends on the design of the equipment. Some will be ok, most will not. Rane typically decouples with a 10 ohm resistor and a .1uf cap, so their statement applies pretty much to their equipment alone. Consoles typically have a solid bond at the star ground in the power supply. Link to comment Share on other sites More sharing options...
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