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Best way to get +4 unbalanced long cable run to +4 balanced input?
Old 26th February 2014
  #1
Lives for gear
 
🎧 15 years
Best way to get +4 unbalanced long cable run to +4 balanced input?

I'm using an old Studiomaster mixer with +4 unbalanced XLR outputs (and 1/4" ouputs as well) and I need to send the signal through a 100ft cable into a recorder that is looking for a +4 balanced signal. Any suggestions on how to do this? Right now I'm doing this... but I'm losing a lot of level:

Mixer -> Radial JDI 1/4 input... XLR out -> 100ft cable -> Radial JDI in reverse 1/4 out -> Recorder.

Any better way to do this?
Old 26th February 2014
  #2
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edva's Avatar
 
26 Reviews written
🎧 10 years
Those JDI's will indeed reduce the level. Have you tried just using an xlr cable? Or maybe TRS-to-xlr?
Old 26th February 2014
  #3
Gear Addict
 
Capashitor's Avatar
 
🎧 10 years
So you are converting line level into Hi-Z guitar level for a long cable run ? Not a good idea at all ! Try one of those neutrik 1:1 balancing xlr plugs on the sending end, will probably work fine.

Neutrik NA2 M-J-TX - Thomann France
Old 26th February 2014
  #4
Lives for gear
 
🎧 15 years
I tried an XLR cable, but I get a lot of hum and noise. Using the JDI boxes I get no hum etc going through these Jensen transformers, but yeah I lose tons of level.

How are those inline Neutriks as far as changing the tone/sound? Are they pretty high quality? Would they work for this application?
Old 26th February 2014
  #5
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1 Review written
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In PRO audio you kind of avoid unbalanced connections altogether (unless there is no possible alternative route in any way) because relatively speaking they give you 6 dB lower S/N and much more crosstalk, which eats up the beauty of your mix. Even in the world of headphones you need a pair with a balanced connection, such as the Ultrasone PRO 900 BAL, that I also recommend. Keeping it balanced is extremely important in recording.
Old 26th February 2014
  #6
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by Beneficial ➑️
I'm using an old Studiomaster mixer with +4 unbalanced XLR outputs (and 1/4" ouputs as well) and I need to send the signal through a 100ft cable into a recorder that is looking for a +4 balanced signal. Any suggestions on how to do this? Right now I'm doing this... but I'm losing a lot of level:

Mixer -> Radial JDI 1/4 input... XLR out -> 100ft cable -> Radial JDI in reverse 1/4 out -> Recorder.

Any better way to do this?
If your recorder is expecting a balanced signal, why are you running a DI in reverse at the other end? All you need is an XLRM->TRS patch cable to get the signal back to 1/4" while keeping it balanced. The reverse DI will convert back to unbalanced, and as the transformer is not a 1:1 ratio between TS and XLR (thus preserving the original unbalanced signal level as best as possible) you will definitely lose a lot of signal.

The DI at the source end is definitely the way to do this, and the JDIs are very good as passive DIs go.
Old 26th February 2014
  #7
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Bobby Baird's Avatar
 
🎧 5 years
Radial Twin-Isoβ„’ - Two Channel Signal Isolator

Mixer unbalanced > to iso >100ft. xlr > recorder
Old 26th February 2014 | Show parent
  #8
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🎧 15 years
Quote:
Originally Posted by Liko ➑️
If your recorder is expecting a balanced signal, why are you running a DI in reverse at the other end? All you need is an XLRM->TRS patch cable to get the signal back to 1/4" while keeping it balanced. The reverse DI will convert back to unbalanced, and as the transformer is not a 1:1 ratio between TS and XLR (thus preserving the original unbalanced signal level as best as possible) you will definitely lose a lot of signal.

The DI at the source end is definitely the way to do this, and the JDIs are very good as passive DIs go.
Just tried without adding the reverse DI at the end, and you're right. Looks like it isn't needed. I still have the issue of extremely low volume level though. My recorder expects a +4 balanced line level signal and it looks like the JDI outputs a quiet, balanced mic level signal.

Is there a way to do this without having to add another mic preamp to the chain before hitting my recorder?
Old 26th February 2014 | Show parent
  #9
Gear Maniac
 
Bobby Baird's Avatar
 
🎧 5 years
Quote:
Originally Posted by Beneficial ➑️
Just tried without adding the reverse DI at the end, and you're right. Looks like it isn't needed. I still have the issue of extremely low volume level though. My recorder expects a +4 balanced line level signal and it looks like the JDI outputs a quiet, balanced mic level signal.

Is there a way to do this without having to add another mic preamp to the chain before hitting my recorder?
You are using the wrong box. JDI is for guitar hi-z input impedance to mic 600 ohm impedance. You need an stereo ISO which accepts balanced or unbalanced +4 signals and goes through jensen transformers to +4 balanced out. This way you will not be altering impedance causing a loss of signal.
Old 26th February 2014
  #10
Registered User
 
1 Review written
🎧 10 years
Have a look at the Ebtech Hum Eliminator - the XLR version. This is such a useful box (and the Line Level Shifter as well for when you do want to boost or attenuate). The Hum Eliminator is just an 1:1 isolation transformer, but the XLR version allows you to connect unbalanced to balanced and vice versa. Unlike a DI box, it does not attenuate the signal. You could use a Radial or Jensen ISO box too for slightly higher quality in theory, but I have no issue with the Ebtech quality.

A transformer is a great way to balance and unbalance a cable.
Old 26th February 2014 | Show parent
  #11
Registered User
 
1 Review written
🎧 10 years
Quote:
Originally Posted by SmoothVibe ➑️
In PRO audio you kind of avoid unbalanced connections altogether (unless there is no possible alternative route in any way) because relatively speaking they give you 6 dB lower S/N and much more crosstalk, which eats up the beauty of your mix. Even in the world of headphones you need a pair with a balanced connection, such as the Ultrasone PRO 900 BAL, that I also recommend. Keeping it balanced is extremely important in recording.
Not really true - which is something you should learn.

Headphones are not a good example, because stereo over three wires like this is NOT balanced - it's a pair of unbalanced signal sharing a common ground.

Balancing in and of itself has nothing to do with voltage level - however, when you sum two identical signals you do double the voltage, and that is where the 6dB boost comes from.

In actual fact, balancing is a necessary evil associated with LONG cable lengths, as a way of rejecting noise. It is an overhead of circuity that causes some loss of integrity in the signal, and that is why very serious high-end studio and hifi stuff tends to be unbalanced where possible. Less is usually more, and if the cable runs are short, noise is not an issue with good cables and good shielding.

In the real world, we aren't dealing with seriously high-end equipment or cables, and compromise is the name of the game in a commercial studio. So yes - it's is practical to run balanced cables for everything. Just be aware of why you are doing it, and don't reject the concept of unbalanced gear for ultra high quality applications.
Old 26th February 2014 | Show parent
  #12
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1 Review written
🎧 5 years
Quote:
Originally Posted by Kiwi ➑️
Not really true - which is something you should learn.

Headphones are not a good example, because stereo over three wires like this is NOT balanced - it's a pair of unbalanced signal sharing a common ground.

Balancing in and of itself has nothing to do with voltage level - however, when you sum two identical signals you do double the voltage, and that is where the 6dB boost comes from.

In actual fact, balancing is a necessary evil associated with LONG cable lengths, as a way of rejecting noise. It is an overhead of circuity that causes some loss of integrity in the signal, and that is why very serious high-end studio and hifi stuff tends to be unbalanced where possible. Less is usually more, and if the cable runs are short, noise is not an issue with good cables and good shielding.

In the real world, we aren't dealing with seriously high-end equipment or cables, and compromise is the name of the game in a commercial studio. So yes - it's is practical to run balanced cables for everything. Just be aware of why you are doing it, and don't reject the concept of unbalanced gear for ultra high quality applications.
No, they connect like this (one USC cable to each ear):

Old 26th February 2014 | Show parent
  #13
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Brent Hahn's Avatar
 
1 Review written
🎧 15 years
Quote:
Originally Posted by SmoothVibe ➑️
No, they connect like this
Are those things active? Do they wanna see -10? +4? What do you plug them into that has female XLR outs? My head hurts.
Old 26th February 2014 | Show parent
  #14
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dheming's Avatar
 
🎧 5 years
Quote:
Originally Posted by Kiwi ➑️
Headphones are not a good example, because stereo over three wires like this is NOT balanced - it's a pair of unbalanced signal sharing a common ground.
He's talking about four wire headphones though.


Quote:
Originally Posted by Brent Hahn ➑️
Are those things active? Do they wanna see -10? +4? What do you plug them into that has female XLR outs? My head hurts.
You plug them into a balanced headphone amp of course: HeadAmp Audio Electronics (GS-X Headphone Amp/Pre-Amp)
Old 27th February 2014 | Show parent
  #15
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Brent Hahn's Avatar
 
1 Review written
🎧 15 years
Quote:
Originally Posted by dheming ➑️
You plug them into a balanced headphone amp of course: HeadAmp Audio Electronics (GS-X Headphone Amp/Pre-Amp)
Until I followed the link, I thought you were being sarcastic.
Old 27th February 2014 | Show parent
  #16
Gear Maniac
 
dheming's Avatar
 
🎧 5 years
Quote:
Originally Posted by Brent Hahn ➑️
Until I followed the link, I thought you were being sarcastic.
Balanced headphones are more of an audiophile thing so you don't see it too much in the pro audio world.
Old 27th February 2014 | Show parent
  #17
Lives for gear
 
🎧 15 years
Quote:
Originally Posted by Kiwi ➑️
Have a look at the Ebtech Hum Eliminator - the XLR version. This is such a useful box (and the Line Level Shifter as well for when you do want to boost or attenuate). The Hum Eliminator is just an 1:1 isolation transformer, but the XLR version allows you to connect unbalanced to balanced and vice versa. Unlike a DI box, it does not attenuate the signal. You could use a Radial or Jensen ISO box too for slightly higher quality in theory, but I have no issue with the Ebtech quality.

A transformer is a great way to balance and unbalance a cable.
Have you ever checked the freq response on that ebtech? Ive read people saying it uses cheap transformers that roll off your low end at 100hz... could be misinformation though.
Old 1st March 2014
  #18
Lives for gear
 
🎧 15 years
I just wanted to follow up on this in case anyone comes across it in the future. I went with an Ebtech HE-2 XLR for $76.00. It's perfect. It took care of all of the noise, and the tone and sound is great.

I read people saying that these use cheap transformers that roll off your low end at 100hz etc. The transformers may be relatively inexpensive, but it was misinformation about the roll off. I checked the full spectrum with the DigiCheck Totalyzer... spectrum analyzer in my RME interface... which is very accurate. The frequency response is flat all the way across the range, with a very subtle increase the closer you get to 20,000 hz.

Anyway, I'm really happy with the Ebtech. It worked out really well.
Old 1st March 2014
  #19
Registered User
 
1 Review written
🎧 10 years
Glad it worked out for you. I really rate those Ebtech products - they frequently save my bacon. I have the XLR Line Level Shifter as well, and the 8 channel rack Hum Eliminator for bigger gigs. I've never noticed audible degradation, and if anything I like a subtle bit of transformer saturation, although I can't say i've really heard them saturate.
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