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Gear / Technical Help => Cables => Topic started by: hexyjones on August 26, 2004, 09:51:54 PM

Title: Advise: making cables for: unbalanced source > Balanced XLR in
Post by: hexyjones on August 26, 2004, 09:51:54 PM
I have some Audio Technica Mics that I think arent too bad - and good for dragging out to smoky dirty beery bars...

I want to make some cables to connect them to the XLR ins on my mixer...I want to add some length as well.

Any special way to handle the unbalanced / balanced? It seems I need to just use the XLR shield and the hot pin?

Is there any jumper needed between the unsused connection in the XLR?

I'm about to bust out the soldering iron so - maybe it will make more sense hands on...
Title: Re: Advise: making cables for: unbalanced source > Balanced XLR in
Post by: hexyjones on August 26, 2004, 11:52:42 PM
I have some Audio Technica Mics that I think arent too bad - and good for dragging out to smoky dirty beery bars...

I want to make some cables to connect them to the XLR ins on my mixer...I want to add some length as well.

Any special way to handle the unbalanced / balanced? It seems I need to just use the XLR shield and the hot pin?

Is there any jumper needed between the unsused connection in the XLR?

I'm about to bust out the soldering iron so - maybe it will make more sense hands on...

Would that mean - a little jumper between pin 1 and 3?


With most all mixers I can think of there is a a noise penalty associated with letting the third connector float so I say try connecting it to ground within the XLR shell itself.

Jon


Title: Re: Advise: making cables for: unbalanced source > Balanced XLR in
Post by: hexyjones on August 27, 2004, 12:11:29 AM
Ok still feeling a bit dumb - but

Here's what I made...(a pair)

1/4 Female Unbalanced----------| 4 feet of mic cable (+, -, shield) |------------->Male XLR

Should I just put the black wire on the ground side of the 1/4 inch female...?
That would accomplish the same thing...?
Title: Re: Advise: making cables for: unbalanced source > Balanced XLR in
Post by: hexyjones on August 27, 2004, 12:24:39 AM
Ok still feeling a bit dumb - but

Here's what I made...(a pair)

1/4 Female Unbalanced----------| 4 feet of mic cable (+, -, shield) |------------->Male XLR

Should I just put the black wire on the ground side of the 1/4 inch female...?
That would accomplish the same thing...?


replying to myself...

On second thought - I think I will add the jumper in the XLR end...

I know this stuff isn't that hard...but its been awhile...

The black wire doesnt mean anything as far as the cable goes...

I actually have the mic schematics and the wiring diagram for the XLR wiring...but for some reason I was having trouble visualizing this...
Title: Re: Advise: making cables for: unbalanced source > Balanced XLR in
Post by: jk labs on August 27, 2004, 12:53:44 AM
Ok still feeling a bit dumb - but

Here's what I made...(a pair)

1/4 Female Unbalanced----------| 4 feet of mic cable (+, -, shield) |------------->Male XLR

Should I just put the black wire on the ground side of the 1/4 inch female...?
That would accomplish the same thing...?


replying to myself...

On second thought - I think I will add the jumper in the XLR end...

I know this stuff isn't that hard...but its been awhile...

The black wire doesnt mean anything as far as the cable goes...

I actually have the mic schematics and the wiring diagram for the XLR wiring...but for some reason I was having trouble visualizing this...


there is a difference depending on where you terminate the black wire: 

Terminating the negative XLR-pin-3 (black wire?) to ground at the "far end" of the interconnect will provide you with common mode noise cancellation! Very useful if the interconnect is long and runs through regions where noise is present and picked up by the wire carrying the signal. (i just posted on this a few days ago).

But now a requirement for good common mode noise cancellation is that the two source impedances, seen by the balanced input stage of the mixer, are the same. So you need to connect to ground through a resistor (+capacitor in series) both picked so that they present the mixer with the same resistance as what the output stage of the microphone yields.

As for the short answer: 4 feet is nothing. Solder black to ground either within the XLR or the 1/4" and enjoy the result. 

Regards
Jon


 
Title: Re: Advise: making cables for: unbalanced source > Balanced XLR in
Post by: hexyjones on August 27, 2004, 01:04:58 AM
Is it possible I would be best served by a pair of Direct Boxes???