Help with a Simple test for determining if Balanced output is cross coupled

[scott2000]

Hello,
I have a Frontier Design Tango24 that I'm trying to determine what type of balanced output it uses. Is there a simple test, aside from the headphone test that requires an accessible jack, that I can use to find out? So far I've wired some TRS to TS cables because I want to unbalance the Frontier's outputs. I've left the ring floating on the TRS ,hot to tip and tied ground to sleeve from the output side and just wired the TS with tip with the normal tip and ground sleeve for the next input. I've run a sine through it and, when I short the ring and sleeve together from the output of the Frontier, ( I just opened the unit and shorted the actual jack plug from inside),I get a big level increase. Does this tell me that the Frontier outputs are in fact cross coupled? And willJust using simple TS to TS cables will give me an unbalanced output from the Frontier? There's no schematic I can find. Does anyone have any knowledge of this unit or can someone tell me if my test is correct and, if not, what can I do to test for this? I'm a bit lost on the concept aside from understanding that it's important to not short pin 3 to ground on an active balanced and to short it on a transformer or cross coupled output...Thanks so much!

 

[JohnRoberts]

Hello,
I have a Frontier Design Tango24 that I'm trying to determine what type of balanced output it uses. Is there a simple test, aside from the headphone test that requires an accessible jack, that I can use to find out? So far I've wired some TRS to TS cables because I want to unbalance the Frontier's outputs.

I guess that means it has TRS outputs?

I've left the ring floating on the TRS ,hot to tip and tied ground to sleeve from the output side and just wired the TS with tip with the normal tip and ground sleeve for the next input.

Unlear perhaps a bad translation into english.

1- ring floating on TRS output?
2- hot to tip... which hot? I will ASSume tip from tip-sleeve.
3-tied ground to sleeve--- I ASSume TS sleeve to TRS sleeve.
4- and just wired the TS with tip with the normal tip??  Perhaps TS tip to TRS tip?
5 and ground sleeve for the next input ??? huh?

I've run a sine through it and, when I short the ring and sleeve together from the output of the Frontier, ( I just opened the unit and shorted the actual jack plug from inside),I get a big level increase.

How are you measuring this...? Signal output on any TRS should be measured between Tip and Ring, sleeve is just a shield ground.  If you measure signal between tip and sleeve (don't do that, sleeve is not guaranteed to be a clean 0V reference) then short the floating ring to sleeve (shield ground), different things will happen depending on the output design topology.

If you experience a  roughly 6 dB (big?) increase on the tip when you short the ring to ground, that suggests a cross coupled output driver with both legs active. The signal level from tip to ring did not change, but since you shorted the ring making it 0V, the tip output voltage increased to make up for the lost level.

Does this tell me that the Frontier outputs are in fact cross coupled?

it would seem so

And willJust using simple TS to TS cables will give me an unbalanced output from the Frontier?

it would appear so

There's no schematic I can find. Does anyone have any knowledge of this unit or can someone tell me if my test is correct and, if not, what can I do to test for this? I'm a bit lost on the concept aside from understanding that it's important to not short pin 3 to ground on an active balanced and to short it on a transformer or cross coupled output...Thanks so much!

Does it work TS to TS? If yes, just do it.

Most modern products are designed to be customer proof, and hard to kill, while I am not familiar with that brand or model.

JR

 

[JohnRoberts]

Thanks JR!

Sorry about my translating.  Yes the Frontier has TRS balanced outputs. I was trying to unbalance them. I made some TRS to TS cables to go from the TRS outputs on the Frontier to some unbalanced inputs. I wasn't sure of the output on the Frontier so I left the ring disconnected on the TrS and tied the tip to one conductor, then the second conductor was tied to the sleeve. I left the ring disconnected here thinking that this may be an active balanced output. I then connected the TS end with the same tip conductor from the output from the Frontier's tip .....basically tip to tip...... Then the second conductor was tied to the sleeve,....

Things did not sound right....I knew the noise floor would be more probably but it was not playing well it seemed...

yes, the output is only valid between tip and ring... with the ring floating it's voltage gets subtracted to the total showing up on the tip.  If the loading (like stray capacitance) on the ring is different from the tip loading, and it surely would be, the reults can be squirrely... so DO NOT FLOAT THE RING.

So I played a sine wav in the DAW from the Frontier, to another unit ,then back to the DAW.....and watched it on the meters ....I opened up  the TRS jack at the Frontier's output and shorted the ring to the sleeve and got I guess a 6db increase on the meter in the DAW......

I've since concluded it was in fact a cross coupled output at the Frontier which is odd to me for an ADDA as I haven't seen one like that yet....

Anyhow, everything is quiet  and sounds fantastic so, I'm hoping I'm on the right track in my testing.......????.....

Also, this means I should be able to use simple TS to TS from the FRontier if I want to unbalance it's outputs and connect to unbalanced inputs??

Thanks again!

I might be tempted to use two conductor shielded wiring between TRS and TS jacks. Connect TS to tip and ring while shorting the ring to sleeve only at the TRS output end.

JR

 

[JohnRoberts]

Thanks!

Yes I'm using the 2 conductor with additional shield....just didn't want to add that to my scenario description........ after connecting the 2 conductors to the tip and sleeve I only shorted the ring to sleeve at the TRS on the output.....

....I'm actually not clear what end is recommended in how to tie the cable shield to with all of the gear's layouts.

  Do you have any recommendations? In one scenario I used the cable shield only at the next input because it actually has a true chassis ground floating from circuit... I just didn't use the shield on the output from the Frontier's  source...... just talking the cable's braided shield,,,not the conductors....

Kind of a gray area from what I've read??? Trial and error???

Thanks so much again!!!

If only one of the products has a 3 wire line cord, tie the shield on that end (real chassis ground), otherwise I would tie the shield on the output (send) end.

JR