Subject: [Harp-L] Microphone Cable

[Greg Heumann <greg@xxxxxxxxxxx>]

>
Not quite that simple. Since you say "used with 1/4" jacks" I'll  
assume you KNOW you're talking about Hi-Z application, but let's be  
clear that XLR is primarily used for Lo-Z applications such as vocal  
mics into PA systems. In the Lo-Z system the XLR cables are wired  
"balanced" - that is, the signal travels on 2 wires, connected to  
pins 2 and 3, and NEITHER is connected to ground. The Shield is  
connected to pin 1 AND ground - ground is actually a separate 4th  
conductor in an XLR system which is the metal case surrounding the 3  
pins.

Now with Hi-Z, you have to be careful because some Hi-Z/XLR mics  
(JT30, Blues Blaster come to mind) are wired "Pin 3 hot" - that is  
Pin 3 goes to your 1/4" jack tip, and Ground/Pin 1 goes to the 1/4"  
jack ring. There is no connection to pin 2. But some other Hi-Z mics  
use Pin 2 instead of Pin 3. And the old Shure 545's with XLR  
connectors were wired different again. So you need to know what your  
mic wants and wire everything properly. There is no advantage to  
using both center wires of an XLR cable in a Hi-Z system, and you  
absolutely SHOULD have the cable shield connected to amp and mic  
ground to avoid hum.

Personally I won't use Hi-Z mics with XLR connectors - I change 'em  
out to switchcraft screw-ons or 1/4" jacks to avoid confusion. If you  
find a cable in my bag with an XLR connector at one end, you can be  
sure it will have an XLR connector at the other, and will be for use  
with my low impedance mics only. I can't tell you however how many  
people mistakenly use a Hi-Z-wired cable (with 1/4" at the amp end)  
with a Lo-Z mic, straight into their Hi-Z amp. It works, but poorly.

/Greg
http://www.BlowsMeAway.com


> Hi All
>      In a normal cable used with 1/4" jacks do I have to use the usual
> cable that is used for this? Or can I use the sort of cable used with
> XLR connectors?
> XLR has two wires down the centre, if I attach one to the tip  
> connector
> and the other to the barrel connector, do the copper sheild wires need
> to be grounded?
> Would there be any advantage to this? Better shielding maybe?
>
> Have a Nice Life
>   Christopher