Output 1, 2, Headphone and XLR/TRS Balanced vs. Unbalanced

rtcook

rtcook

Experienced
Ok. Somebody tell me if I am on the right track or not. I want to use my headphones to practice and not disturb others at night. When I plug them in my monitors connected to Output 1 XLR do not silence as expected. I have read the headphones and Output 1 are the same. In order to make this work I have to shut off the power to my monitors and all is well. I also read that I could run my monitors off Output 2. That way I can just turn down Output 2 on the front panel when using headphones and use Output 1 knob to adjust the headphone level. So far so good I think. But, Output 2 is an unbalanced output. I am currently using the balanced Output 1 XLR to my monitors thinking I am helping reduce noise with this type of cable. If I use the Output 2 I will need to buy new XLR to TRS cables instead of my current XLR to XLR cables. My question is will I be introducing the possibility of noise? The cables need only to be 10' and I am playing at home. What do you guys think? Doing this right or do you have a better suggestion?

Thanks,

Roger
 
I will always, always, always use balanced audio and if I can't then I won't dork with it. It's not worth the hassle and chance of noise being introduced into the signal path.

The idea of using the XLR to TRS cables sounds good on paper, but the 2nd output uses humbuster wiring which is actually for TRS to TS with the ground and negative connected on one end. It's also going to be several dB lower in volume since it's actually an unbalanced signal.

I'd suggest just turning the monitors off. I've actually got a slightly similar problem, but I do have a monitor/headphone mixing system so I can deal with the levels, but I have to basically climb behind my desk to turn my monitors on and off. I'm thinking about getting a rackmount strip with multiple switches on it. I found a few on e-Bay for about $30 shipped.
 
Ok. Your reasoning has crossed my mind and actually turning the monitors off is really not that difficult. I just read about the humbuster cable and thought it was an option. Doesn't seem to be worth it at this point spending the extra money and possibly introducing noise for the limited headphone use. Thanks for your input. Much appreciatied.

Roger
 
shasha said:
I will always, always, always use balanced audio and if I can't then I won't dork with it. It's not worth the hassle and chance of noise being introduced into the signal path.
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i've honestly never experienced noise using unbalanced cables in over 15 years of performing.

how often is there noticeable noise when you use unbalanced?
 
I wouldn't be worried about using Out 2 if it's more convenient. You could listen for noise using Out 1 XLR to one monitor and Out 2 1/4" to the other. I'd disconnect the grid path because you're not listening for guitar/input noise through an amp sim here, just whether the unbalanced connection itself is noisier. Remember that turning the Axe up and monitor down will increase signal relative to noise picked up by the cable.

TRS to XLR works fine. I'm guessing this just makes the humbuster circuitry do nothing.
 
Ok. What's your take on hooking it up with humbuster cables instead of XLR male Mic to TRS? I can get the humbuster cables from Best-Tronics much cheaper than the Mogami Gold's I'm using now.

Bakerman said:
I wouldn't be worried about using Out 2 if it's more convenient. You could listen for noise using Out 1 XLR to one monitor and Out 2 1/4" to the other. I'd disconnect the grid path because you're not listening for guitar/input noise through an amp sim here, just whether the unbalanced connection itself is noisier. Remember that turning the Axe up and monitor down will increase signal relative to noise picked up by the cable.

TRS to XLR works fine. I'm guessing this just makes the humbuster circuitry do nothing.
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rtcook said:
Ok. What's your take on hooking it up with humbuster cables instead of XLR male Mic to TRS? I can get the humbuster cables from Best-Tronics much cheaper than the Mogami Gold's I'm using now.
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No reason when there's not enough ground loop noise to make a decrease noticeable. But it wouldn't hurt either, and they'd be useful if you ran into that scenario later.

I'd just try the noise test first. With a completely muted preset, do you hear any difference in noise from the monitor when connecting XLR from Out 1, TRS from Out 2, nothing at all? Disconnect cable end from monitor for 3rd part.
 
Chris@KatsuKuriMedia said:
Really? Wow.
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Yeah, really. That's why they came up with balanced audio and it's used in almost all professional equipment. :)

Now I will put one caveat out there in terms of my personal experiences on this. I don't go out and do gigs and stuff; this is all based on over 20 years designing and installing production and on-air studios. Most of the time (actually every time) it's going to be an entire facility so yeah there's a lot more gear involved which just simply means more interference floating around. And because we are connecting equipment throughout a building you are going to have different ground potentials no matter how good your grounding technique is; it also means that we have ridiculously long runs and each cable acts like a an antenna in both directions.

Another thing is that unbalanced audio requires that you connect the ground between two devices (unless you put an isolation transformer in line). Balanced audio you just lift the ground on the source (or destination, but just maintain consistency throughout) and you eliminate your ground loop potentials.

You are also looking at a +4dBm signal vs a -10dBm signal; the stronger the signal the higher the SNR.

There is just no reason to choose unbalanced over balanced if you have the ability to use both.

Once again though this is just my personal opinion and experience. If it works for you and you are happy than it isn't wrong.
 
Oh ok that explains it. I mostly do live and stages, not broadcast. So yes, balanced is always better. But I feel there shouldn't be any "fear" about using an unbalanced connection :) It too was developed and still employed for a reason :)
 
shasha said:
Yeah, really. That's why they came up with balanced audio and it's used in almost all professional equipment. :)

Now I will put one caveat out there in terms of my personal experiences on this. I don't go out and do gigs and stuff; this is all based on over 20 years designing and installing production and on-air studios. Most of the time (actually every time) it's going to be an entire facility so yeah there's a lot more gear involved which just simply means more interference floating around. And because we are connecting equipment throughout a building you are going to have different ground potentials no matter how good your grounding technique is; it also means that we have ridiculously long runs and each cable acts like a an antenna in both directions.

Another thing is that unbalanced audio requires that you connect the ground between two devices (unless you put an isolation transformer in line). Balanced audio you just lift the ground on the source (or destination, but just maintain consistency throughout) and you eliminate your ground loop potentials.

You are also looking at a +4dBm signal vs a -10dBm signal; the stronger the signal the higher the SNR.

There is just no reason to choose unbalanced over balanced if you have the ability to use both.

Once again though this is just my personal opinion and experience. If it works for you and you are happy than it isn't wrong.
Click to expand...

wouldn't that be +4dBu (or dBm) vs -10dBV
 
javajunkie said:
wouldn't that be +4dBu (or dBm) vs -10dBV
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Yes you are right. It's dBu (which I should know better), but the consumer stuff I just assumed that it was the same unit of measurement. Didn't realize that they measure it in reference to Voltage. I'm just used to measuring levels with a 600Ω termination which is why dBm was on the brain.

Either way it's pretty bad considering dBm is a 600Ω terminated to 1mW reference and I know that unbalanced stuff is in the 10kΩ range. Kind of hard to have an apples to apples comparison.
 
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