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Author Topic: How to test jack for balanced/unbalanced  (Read 17495 times)

Steve Schow

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Re: How to test jack for balanced/unbalanced
« Reply #20 on: November 01, 2012, 05:26:17 pm »

Have you tried asking the manufacturer?

What DCR do you measure T-S and R-S? (with unit on but not passing audio).

This isn't all that hard.

JR

PS: I can't imagine a manufacturer going backwards. It cost pocket change to balance a termination with an extra resistor. The major cost there is the TRS jack not the resistor.

Yes I mentioned earlier that I emailed the manufacturer "Vox" on their tech support line, and they ultimately told me that they were just a humble distributorship and didn't know the answer to deep technical issues like this, they can pretty much only read the manual like I can.  Originally this unit was some kind of joint project with Vox and Korg, so I don't know, there is a breakdown in communication somewhere.  They tended to take the position that it was NOT balanced, based on the fact that the manual does not state either way.

I agree it would be bad to go backwards, but they did make it a smaller unit, so anything is possible. 

I have to buy the test equipment before I can measure what you suggested.  I plan to go to Radio Shack later.  I wanted to have one of those anyway.

I tried already putting in my headphones.  Headphones only hears audio on one side.  And if plugged in only halfway (in an attempt to hit the ring contact with the tip), it does not hear any audio.

I'm tending to think right now they are unbalanced.  The original unit was able to support both balanced and unbalanced connections and I'm not sure how they detect if its balanced or not before creating the balanced signal.  so if this unit has some kind of auto mode to be balanced or unbalanced depending on usage, I wonder if the only way to engage the balancing is to actually plug the other end into balanced input.  But the other end also has auto detection feature to be balanced or unbalanced, so I don't know how I would find out whether I have clicked into balanced mode or not.
« Last Edit: November 01, 2012, 05:30:05 pm by Steve Schow »
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g'bye, Dick Rees

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Re: How to test jack for balanced/unbalanced
« Reply #21 on: November 01, 2012, 05:53:17 pm »

I have a device with 1/4 inch outputs .........
  What other info do you feel I am leaving out?

Exactly what is this device?  I assume it's not a bicycle although you haven't ruled that out by your description.......

When I'm confronted by any such situation and have access to all the components, I just hook it all up and see if it works.  If it doesn't, then I fix it.
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Steve Schow

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Re: How to test jack for balanced/unbalanced
« Reply #22 on: November 01, 2012, 06:08:55 pm »

Exactly what is this device?  I assume it's not a bicycle although you haven't ruled that out by your description......
As stated already, its a Vox Tonelab LE

Quote
When I'm confronted by any such situation and have access to all the components, I just hook it all up and see if it works.  If it doesn't, then I fix it.
As stated several times I will be using a snake, which I need to prepare.  Either the snake needs two unbalanced lines or two balanced lines. 

Alternatively I could just make the snake balanced, but then the question becomes, do i need to buy a line balancer or not and how will I know other than hook it up and if it sounds bad buy a line balancer in hopes that will solve it.

Guitar stuff has a lot of noise on its own, so its really hard to know for sure whether the noise we hear is coming from the guitar or from a long unbalanced line.  Nonetheless, trying to minimize noise wherever I can.

Because the input at the other end is going into a device that accepts both balanced and unbalanced signals, I will not really know for sure whether I am accomplishing a balanced run until some gig in a location where the obvious lack of balanced lines shows its ugly face.


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Andrew Broughton

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Re: How to test jack for balanced/unbalanced
« Reply #23 on: November 01, 2012, 06:23:06 pm »

Get a Q-Box.
Connect it up with a TRS to XLR adapter with tip connected to pin 2, ring to pin 3, sleeve to pin 1. Put some signal through your DUT. Switch the input on the Q-Box (using the pin 2/pin 3/pin 2&3 switch). If you get sound out of the speaker in all settings, then it's differentially balanced.
STOP.

If you get sound only when the switch is in pin2 and pin 2&3 mode, then it's not differentially balanced and MIGHT be unbalanced.
So now take an ohmmeter and measure the resistance between tip and sleeve, then ring and sleeve. If they are the same and non-zero (below 1k ohms), then you have an impedance-balanced output.
If ring to sleeve is 0 or infinity, you have an unbalanced output.
« Last Edit: November 01, 2012, 06:32:12 pm by Andrew Broughton »
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Steve Schow

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Re: How to test jack for balanced/unbalanced
« Reply #24 on: November 01, 2012, 06:48:33 pm »

Get a Q-Box.
Connect it up with a TRS to XLR adapter with tip connected to pin 2, ring to pin 3, sleeve to pin 1. Put some signal through your DUT. Switch the input on the Q-Box (using the pin 2/pin 3/pin 2&3 switch). If you get sound out of the speaker in all settings, then it's differentially balanced.
STOP.

If you get sound only when the switch is in pin2 and pin 2&3 mode, then it's not differentially balanced and MIGHT be unbalanced.
So now take an ohmmeter and measure the resistance between tip and sleeve, then ring and sleeve. If they are the same and non-zero (below 1k ohms), then you have an impedance-balanced output.
If ring to sleeve is 0 or infinity, you have an unbalanced output.

+1 Andrew, thanks for that step by step, I will try that as soon as I get my hands on a cable tester and ohm meter.
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Re: How to test jack for balanced/unbalanced
« Reply #25 on: November 01, 2012, 06:57:17 pm »

+1 Andrew, thanks for that step by step, I will try that as soon as I get my hands on a cable tester and ohm meter.

The manual shows it to be a TS connector for what that's worth......
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Ned Ward

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Re: How to test jack for balanced/unbalanced
« Reply #26 on: November 01, 2012, 07:14:57 pm »

Tonelab LE outputs ->Stereo DI ->snake.

Problem solved, whether it's balanced or not.

Just use a DI and you don't have to suss out which is which. You'll also eliminate other potential issues with a good DI in place; I'd recommend the Radial ProDI2.
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Steve Schow

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Re: How to test jack for balanced/unbalanced
« Reply #27 on: November 01, 2012, 07:16:14 pm »

The manual shows it to be a TS connector for what that's worth......

Can you please show me where it says that?  I see no indication of TS and this has been asked a lot on Tonelab related forums
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Steve Schow

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Re: How to test jack for balanced/unbalanced
« Reply #28 on: November 01, 2012, 07:18:15 pm »

Tonelab LE outputs ->Stereo DI ->snake.

Problem solved, whether it's balanced or not.

Just use a DI and you don't have to suss out which is which. You'll also eliminate other potential issues with a good DI in place; I'd recommend the Radial ProDI2.

hehe if it comes down to it that is exactly what I will do NW, or possibly an Ebtech Hum Eliminator.
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Re: How to test jack for balanced/unbalanced
« Reply #29 on: November 01, 2012, 07:30:43 pm »

Can you please show me where it says that?  I see no indication of TS and this has been asked a lot on Tonelab related forums

It doesn't say it, it shows it.  Look at the pictographs.  The headphone jack is shown as a TRS stereo connector but the line out connections are depicted as TS. 
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Re: How to test jack for balanced/unbalanced
« Reply #29 on: November 01, 2012, 07:30:43 pm »


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