Unbalanced to balanced cable?

[Eric Desrochers]

While going from an unbalanced source to a balanced input using a short
cable, would you use :

1) A simple hot/shield cable with the shield connected to pin 1 and 3 at
the XLR end and at gnd at the source

2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd at
the unbalanced end) and the shield to pin 1 but floating at the
unbalanced end?

And why? Thanks!

--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95

[henryf]

Eric Desrochers wrote:

> While going from an unbalanced source to a balanced input using a short
> cable, would you use :
>
> 1) A simple hot/shield cable with the shield connected to pin 1 and 3 at
> the XLR end and at gnd at the source
>
> 2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd at
> the unbalanced end) and the shield to pin 1 but floating at the
> unbalanced end?
>
> And why? Thanks!
>

No, I wouldn't use either of these methods. Why? Because for
your particular application it seems the resulting signal will
be 12 dB too weak.

[Phil Allison]

"Eric Desrochers" <

> While going from an unbalanced source to a balanced input using a short
> cable, would you use :
>
> 1) A simple hot/shield cable with the shield connected to pin 1 and 3 at
> the XLR end and at gnd at the source


** That will always work - but may create a hum loop.



> 2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd at
> the unbalanced end) and the shield to pin 1 but floating at the
> unbalanced end?


** That depends whether your unbalanced device has mains ground linked to
its output.

If not expect lots of hum.




............. Phil

[e]

Balanced to Unbalanced Converter
http://www.rdlnet.com/fpbuc2.htm

emil


"Phil Allison" > wrote in message
u...
>
> "Eric Desrochers" <
>
> > While going from an unbalanced source to a balanced input using a short
> > cable, would you use :
> >
> > 1) A simple hot/shield cable with the shield connected to pin 1 and 3 at
> > the XLR end and at gnd at the source
>
>
> ** That will always work - but may create a hum loop.
>
>
>
> > 2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd at
> > the unbalanced end) and the shield to pin 1 but floating at the
> > unbalanced end?
>
>
> ** That depends whether your unbalanced device has mains ground linked to
> its output.
>
> If not expect lots of hum.
>
>
>
>
> ............ Phil
>
>

[Phil Allison]

"e" > wrote in message
...
> Balanced to Unbalanced Converter
> http://www.rdlnet.com/fpbuc2.htm
>
> emil



** You must be related to "Wrong Way Corrigan" .



............ Phil

[Scott Dorsey]

Eric Desrochers > wrote:
>While going from an unbalanced source to a balanced input using a short
>cable, would you use :
>
>1) A simple hot/shield cable with the shield connected to pin 1 and 3 at
>the XLR end and at gnd at the source

This is fine for a short run.

>2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd at
>the unbalanced end) and the shield to pin 1 but floating at the
>unbalanced end?

This gives you a little bit of noise rejection. It's probably a better idea
for a longer run.

3) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd
through a resistor equal to the output impedance of the unbalanced device
driving it), and the and the shield to pin 1 but floating at the unbalanced
end.

This gives you the best noise rejection.

Floating the pin 1 connection may or may not be a good idea depending on
how your grounds are arranged. You want one and only one signal ground
connection from each device to each other. If you don't have it, you may
get noise problems from poorer shielding. If you have too many, you may
get noise problems from ground loops.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Mike Rivers]

In article > writes:

> While going from an unbalanced source to a balanced input using a short
> cable, would you use :
>
> 1) A simple hot/shield cable with the shield connected to pin 1 and 3 at
> the XLR end and at gnd at the source

If it works.

> 2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd at
> the unbalanced end) and the shield to pin 1 but floating at the
> unbalanced end?

If it works better. Or also consider connecting the shield at both
ends.

> And why?

Because outputs, inputs, and grounding are different on equipment
build by different manufacturers. There's a certain amount of fudging
you can do to make a bad situation better, and there are certain
combinations that work just about the same no matter what you do as
long as you have signal continuity.

I'd make up a two-conductor shielded cable and just try all the
combinations of shield connected at one end, the other end, and both
ends. Use what hums the least.


--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

[Ben Bradley]

In
rec.audio.pro,
alt.audio.pro.live-sound,
(Eric Desrochers) wrote:

>While going from an unbalanced source to a balanced input using a short
>cable, would you use :
>
>1) A simple hot/shield cable with the shield connected to pin 1 and 3 at
>the XLR end and at gnd at the source
>
>2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd at
>the unbalanced end) and the shield to pin 1 but floating at the
>unbalanced end?

I would follow what it says on this webpage:

http:/www.rane.com/note110.html

>And why?

Because it's all been worked out for me, even the trademark
attribution: "Band-Aid is a registered trademark of Johnson & Johnson"

>Thanks!
>
>--
>Eric (Dero) Desrochers
>
>Hiroshima 45, Tchernobyl 86, Windows 95

I heard it's up to Windows 2000.

[Arny Krueger]

"Eric Desrochers" > wrote in message


> While going from an unbalanced source to a balanced input using a
> short cable, would you use :

> 1) A simple hot/shield cable with the shield connected to pin 1 and 3
> at the XLR end and at gnd at the source

The problem with this is that it throws away one of the major benefits of
that balanced input - its rejection of hum from various sources. People keep
saying that the length of the cable should affect your choice, but IME this
kind of connection can lead to unnecessary hum even when the cable is just a
few feet long.

> 2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd
> at the unbalanced end) and the shield to pin 1 but floating at the
> unbalanced end?

This is my choice, whenever possible. There should be some kind of other
connection joining the two chassis if they aren't tied together any other
way. I've been known to dress the pin 1 wire out, put some sleeving over
it, and terminate it with a spade connector or alligator clip.

> And why? Thanks!

I don't like to have to screw around getting rid of hum.

[Mike Dobony]

"Eric Desrochers" > wrote in message
...
> While going from an unbalanced source to a balanced input using a short
> cable, would you use :
>
> 1) A simple hot/shield cable with the shield connected to pin 1 and 3 at
> the XLR end and at gnd at the source
>
> 2) A balanced cable with +cable to pin 2, -cable to pin 3 (and to gnd at
> the unbalanced end) and the shield to pin 1 but floating at the
> unbalanced end?
>
> And why? Thanks!
>


What is wrong with a transformer or DI box?

--
Mike D.

www.stopassaultnow.org

Remove .spamnot to respond by email

> --
> Eric (Dero) Desrochers
>
> Hiroshima 45, Tchernobyl 86, Windows 95


---
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[Eric Desrochers]

Mike Dobony > wrote:

> What is wrong with a transformer or DI box?
>
> --
> Mike D.

More complicated, more expensive, possibility of irregular frequency
response, saturation, additional noise, etc.

I want to keep it simple. It's for a home setup (home stereo, not home
studio).

I should have been clearer! :) Unbalanced source have 100 ohm output
impedance, can put out >10 volts and is not grounded to earth by the AC
plug (2 prongs plug). Input unit is balanced 2 X 10k ohms and is
possibly grounded to earth by a 3 prongs plug. Cable length is 6 feet.

Thanks all for the replies. The Rane reference was very helpfull in
particular.
--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95

[Joe L]

<Found on the Rane tech page>

"When all else fails, digitize everything, use fiber optic cable and enter a
whole new realm of problems."




Joe L

[S O'Neill]

They have some hilarious stuff on that site. Look at their psychoacoustic
infector: http://www.rane.com/pdf/old/pi14dat.pdf

Joe L wrote:

> <Found on the Rane tech page>
>
> "When all else fails, digitize everything, use fiber optic cable and enter a
> whole new realm of problems."
>
>
>
>
> Joe L
>
>

[Rob Reedijk]

Phil Allison > wrote:

> "e" > wrote in message
> ...
>> Balanced to Unbalanced Converter
>> http://www.rdlnet.com/fpbuc2.htm
>>
>> emil

> ** You must be related to "Wrong Way Corrigan" .

That would be for an intentional mistake.

Maybe you mean "Wrong Way Feldman".

Rob R.