RCA to XLR cable, where to connect the sleeve?

[klitgt]

I plan to make DIY cables to connect my single ended unbalanced preamp (RCA output sockets) to a poweramp with balanced XLR inputs.

I have searched this site and found an extensive overview of possibilities here

What are XLR connections??

Scroll half way down and look at number 17, "From output RCA to XLR input".
The shield connects to the input end only (at the XLR pin1).

I always thought that "pseudo-balanced" cables must have the shield connected at the output end (in this case the sleeve of the RCA plug) and NOT connected to the input plug sleeve/ground.
This is the case if RCA plugs are in both ends of a "pseudo-balaced" RCA to RCA cable.

I believe there is nothing wrong with connecting the shield at both ends, see attached pic.

So the 1000$ question is: Is No. 17 correct, is my suggestion (attachment) correct or should the shield in my pic only connect to the RCA sleeve and not to the XLR pin1?
What is actually the best way to make a RCA to XLR cable?

[audiopro]

Your diagram is fine, your worrying over nothing. Alternatively though, connect pins 1 and 3 together at the XLR and connect the shield at the RCA. I prefer to have the shield connected at the source end only.

[Frank Berry]

I agree with audiopro.
"Connect pins 1 and 3 together at the XLR and connect the shield at the RCA".

By doing it this way, there will be no audio current flowing through the shield.

[K-amps]

If there is signal at either 1 or 3, by doing this, you are shorting the output to ground are you not? Are we assuming that the output has enough protection for a short at the output... surly there must be some ill effects... I am just asking.

[Frank Berry]

You are merely forcing the balanced input of the power amplifier to operate unbalanced. The positive (hot) wire is connected to pin #2 on the XLR.

[K-amps]

On the input yes I agree, but what about the source... If someone uses a balanced source, you'd be shorting it out ..yes?

[richie00boy]

Originally posted by Frank Berry
I agree with audiopro.
"Connect pins 1 and 3 together at the XLR and connect the shield at the RCA".

By doing it this way, there will be no audio current flowing through the shield.

This can be confusing as your statement is only correct if he still uses balanced cable and uses the cold wire to connect to the RCA. This has the disadvantage though that open ended shields have the possibility to act as a handy RF antenna.

If he uses ordinary screened cable and connects as you say there will be audio current flowing in the shield this way: audio is an AC signal and thus will be looping round the signal and screen.

klitgt, your proposed diagram is correct. I suggest that you connect that way, NOT connecting pins shield and cold together at the XLR as that will not offer any rejection of possible ground current in the shield. This also complies with the latest AES guidance.

[klitgt]

Originally posted by audiopro
Your diagram is fine, your worrying over nothing. Alternatively though, connect pins 1 and 3 together at the XLR and connect the shield at the RCA. I prefer to have the shield connected at the source end only.

So you suggest that the recipe here

What are XLR connections??

should be reversed as to the connection of the shield (to the RCA sleeve and not to the XLR ground pin1) AND that the XLR cold pin3 is connected to the XLR ground pin1.

Both suggestions will leave an open ended shield that richie00boy does not recommend as he believes it will create a "handy RF antenna".

For info I use a cable that has 2 leads (each isolated) surrounded by a shield and then an outer isolating tube.

I will go for my original suggestion until I see other convincing solutions to the challenge (as I prefer to call what many call problems)

[SvErD]

I support Richie and Frank and recommend no. 2 for your application(unbal. preamp to bal. poweramp) and suggest no. 3 for bal. preamp to unbal poweramp.

[richie00boy]

I recommended #1 which was not quite what Frank recommended.

I still stick with my original suggestion, but add that it may be worth trying with and without shield connected at the RCA end. Try with first