balanced cable with unbalanced outputs?

[quincyg]

sorry to ask this question, but i am still unclear after doing some searching. it was suggested to me that maybe my unbalance outputs of my smart c1 are not connected correctly to my system.

all of my patchbay breakout cables are wired trs connectors and wired trs to the bay. i did this because i had read that when i use a balanced cable on an unbalanced output the ring is simply taken out of the equation. is this wrong? should i be changing the connectors at the unbalanced ends or lifting the ground?

thanks much!

[dementedchord]

naw you got it right the ring is grounded if unballanced is inserted... the only caveate (and its kinda rare) is IF the balanced output of say a preamp is real low... it can cause havoc for the pre.... but like i said rare...

[XSergeantD]

you're trying to send an unbalanced line down a balaced cable sending it single ended. Signal on an unbalanced cable is say 1.23v from tip to sleeve. Balanced cables run 1.23v from pin 2-3 or tip to ring. As your jacking in a balanced cable into an unbalanced jack your ring is free floating. sounds like dementedchord thinks you're patching an unbalanced cable into a balanced output

[quincyg]

i do understand what gets sent on what pin. i don't understand what psysically happens when you insert a balanced cable into an unbalanced jack. i think it goes like this.

tip---goes to---tip
ring--goes to---nothing
sleeve---goes to ----sleeve

here is a quote from a sound on sound article:

"Q: what is the best way to connect unbalanced signal sources to balanced inputs?

A: The traditional method is to use balanced cable and connect the cold to the screen at the unbalanced end. however, this can sometimes result in ground loop hum poroblems, ao it is safer to connect the unbalanced end of the cable as follows.

connect the screen to the ground pin via a resistor of between 100 and 500 ohms or leave it disconnected altogether. connect the cold core of the cable to the connector pin normally used to connect the screen. connect the hot to the normally hot pin."

-end quote-


So basically the cold gets moved over to pin one and pin shield gets lifted.


Then i just read a meyer sound article that says the afore mentioned method is often problematic and the first choice should be to not lift the shield and simply put the cold and the shield to the sleeve. maybe the resistor improves upon this method.

So I really don't know what to believe.

Am I ok as is?
Do i lift ground or put a resistor on ground and move cold to tip?
Do i not lift ground and move cold to tip with no resistor?

And lastly, how do i check to see if a given method is correct?

[Tim Farrant]

This is a problem with using jack plugs - but, as time goes on, more and more manufacturers (who are worthy of their salt) are using sockets with a ring grounded on unbal outputs. I think Mackie have done this for quite a while now.

But, if the bal input does not like what is feeding it due to a bad ring connection, it will probably show up as noisy or have some buzz on it. Bad connections will reveal themselves, if ya got NO NOISE - NO PROBLEM!

Cheers
Tim

[quincyg]

Originally Posted by Tim Farrant

This is a problem with using jack plugs - but, as time goes on, more and more manufacturers (who are worthy of their salt) are using sockets with a ring grounded on unbal outputs. I think Mackie have done this for quite a while now.

But, if the bal input does not like what is feeding it due to a bad ring connection, it will probably show up as noisy or have some buzz on it. Bad connections will reveal themselves, if ya got NO NOISE - NO PROBLEM!

Cheers
Tim

ok, so noise is the only issue. i started looking into this because someone suggested that i may not be totally satisfied with my c1 because of improper unbalanced connection to it. i also read a line in the meyer sound document which mentioned frequency distortion as a possible effect of improper wiring. if noise is the only issue, then i am good.

would i possibly create problems if i did do the old resistor method?

[dementedchord]

MY BAD... good save thnx brent... i'm only 53 you'ld a thought i woulda learned to read by now...

[XSergeantD]

you'll either have noise or your signal will be 6db low.

you can see the single ended situation by looking at the previous pics, and maybe this will help you.



for unbal source to bal in: * - Some balanced phone-plug inputs are designed so that you can plug an unbalanced two-conductor plug directly into them.

for Bal source to unbal input: ** - If the source has a transformer output (some high-end gear and most of the classic stuff), connect this to ground as well.