Re: [Harp-L] question about mic connection

[Greg Heumann <greg@xxxxxxxxxxx>]

This is an area of confusion for everyone - they don't teach you this in school. 

The SM58 is a low impedance mic. Your amp has a high impedance input.

When you see a cable that has an XLR connector at one end and 1/4" at the other, you're looking at a cable designed to use with high impedance mics. Not only does it not match the impedance, the internal wiring of such a cable is DIFFERENT from a low impedance cable. In fact it doesn't connect at all to one of the pins upon which your SM58 is outputting its signal. You will get some sound, but it will be about half of the mic's output. 

The PROPER way to connect them is to use a standard low impedance cable (XLR female to XLR male) and an "Impedance Matching Transformer" ("IMT") at the amp end of the cable. The IMT has an XLR connector at one end and a 1/4" connector at the other. This solution not only matches impedance but also routes the mic's signal properly and you will get its full output. 


For much more on the subject, you might want to read this doc:

http://blowsmeaway.com/all%20about%20harmonica%20microphones.pdf

Which is "All about harmonica microphones and then some." It covers this subject and many more. 

/Greg

http://www.blowsmeaway.com
http://www.bluestateband.net
http://itunes.apple.com/us/album/duracool/id343874731




> From: dcarter@xxxxxxxxx
> Date: April 26, 2011 6:26:23 AM PDT
> To: "Harp-L" <harp-l@xxxxxxxxxx>
> Cc: harp-l@xxxxxxxxxx
> Subject: [Harp-L] question about mic connection?
> 
> 
>     Hey all, I have been looking into getting a Shure SM58 to use on a
> mike stand. So I can play some acousticly off of that. But they have a
> different type of connector than the amp I have, do I just get a cable
> that has the proper connector on the amp end? Or is there an adaptor that
> I would purchase for the amp end of the cable that comes with the mic? I
> just don't know much about this amplified stuff yet.