Did I just mess up my equipment

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Razzle1980

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So I'm a newbie to this recording thing. I'm running a Neve 5017 preamp into a Yamaha AG03 mixer. I'm using Cubase as my DAW. While I'm trying to educate myself as I go, I realized that I made two mistakes, and I'm wondering if I may have messed anything up.

1) For the past 3 weeks, I had the output of my Neve preamp (balanced) going to the guitar input of my Yamaha interface/mixer (unbalanced) using a balanced cable. I learned today that it should actually be plugged into the line input on my I interface/mixer. Any potential harm in having done this for the past 3 weeks?

2) I was "experimenting" with my interface/mixer and I plugged the balanced output of my Neve preamp into the XLR input of the Yamaha interface/mixer using a balanced cable. While it was plugged in there, I pressed the phantom button on the interface/mixer for less than 5 seconds and then turned it off, not knowing what it was for. Did I fry anything?

Thanks,
 
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You should be fine. The phantom shouldn't have messed up the preamp and there is no harm plugging into the guitar input.

What are you using as an interface? You should plug the neve directly into the line input of the interface. (Assuming the mixer isn't the interface)
 
Hey Farview, thanks for the reply. My Yamaha AG03 is the interface/mixer. Both my interface (Yamaha) and pre-amp (Neve) have the phantom buttons. For clarification purposes, I pressed the phantom button on my interface with a balanced cable plugged in from output of pre-amp to XLR input on interface.
 
You should still be fine. The neve output is line level, so should be plugged into a line level input, not the mic input. This is mainly for gain staging purposes.

The neve preamp takes the mic signal and boosts it to line level. So you want to plug that in to an input that expects a line level signal.
A common mistake is confusing the type of connector with the signal it carries. For.example, an xlr cable can carry line level, mic level, aes/ebu, etc... so it is up to you to know what type of signal you are connecting to what.
 
Is this perhaps contributing to your crackling problem? sticking a line in into an instrument level input usually means the gain control ends up being quite low and it messes the gain staging up. Incidentally - if you're getting used to your new system, it's well worth experimenting with mics into snazzy preamp then into the interface and then repeating it without the clever preamp straight into the interface and listening to how things change. If you use more gain on the Neve and less on the interface, vs less on the Neve and making it up in the interface. One will probably sound a little more stressed and less nice.
 
Hi Roy, I had the same problem after switching the input from instrument to line on the interface. I'm thinking the buzzing came be from the fact that the volume to each track was higher than what I should have set it to.
 
If you are using a "balanced" (TRS/"stereo") 1/4" cable from the preamp, chances are it's only the XLR-combo jack's input that actually has a balanced 1/4" connector. And, if you use the combo 1/4" input, you might try it with the PAD engaged to see if it changes the noise level. If it does, that suggests the noise is entering from the external input.
 
Hi there,

It's good that you're educating yourself as you go - that's the best way to learn! You made two mistakes, which may have caused some damage.

1) You should have been plugging your Neve preamp into the line input on your Yamaha interface/mixer, rather than the guitar input. This is because the guitar input is designed for unbalanced signals, while the line input is designed for balanced signals. By plugging your preamp into the guitar input, you may have caused some noise or other issues.

2) You were using a balanced cable when you should have been using an unbalanced cable. This is because unbalanced cables are less prone to noise and interference than balanced cables. By using a balanced cable in this situation, you may have introduced some unwanted noise into your signal chain.

Hopefully this has helped clear up what went wrong - sorry if it was bad news! Always be sure to do your research before starting to record, so that you can avoid making these kinds of mistakes.
--
Jason Hook. Audio Enthusiast and Software Developer
Remove or Isolate Vocals from any Song 👉 https://www.UnMixIt.com/
 
TheSynthDev said:
Hi there,

It's good that you're educating yourself as you go - that's the best way to learn! You made two mistakes, which may have caused some damage.

1) You should have been plugging your Neve preamp into the line input on your Yamaha interface/mixer, rather than the guitar input. This is because the guitar input is designed for unbalanced signals, while the line input is designed for balanced signals. By plugging your preamp into the guitar input, you may have caused some noise or other issues.

2) You were using a balanced cable when you should have been using an unbalanced cable. This is because unbalanced cables are less prone to noise and interference than balanced cables. By using a balanced cable in this situation, you may have introduced some unwanted noise into your signal chain.

Hopefully this has helped clear up what went wrong - sorry if it was bad news! Always be sure to do your research before starting to record, so that you can avoid making these kinds of mistakes.
--
Jason Hook. Audio Enthusiast and Software Developer
Remove or Isolate Vocals from any Song 👉 https://www.UnMixIt.com/
Click to expand...
What sort of damage could I have caused?

Also, I'm a bit confused about your second point. Are you saying that I should be using an unbalanced cable to connect from my Neve's line out to my interface's line in? I thought that cable should be balanced.
 
TheSynthDev said:
2) You were using a balanced cable when you should have been using an unbalanced cable. This is because unbalanced cables are less prone to noise and interference than balanced cables. By using a balanced cable in this situation, you may have introduced some unwanted noise into your signal chain.

Jason Hook. Audio Enthusiast and Software Developer
Remove or Isolate Vocals from any Song 👉 https://www.UnMixIt.com/
Click to expand...
Jason, you've got this exactly backwards. A balanced cable is less likely to have noise and has better signal integrity because the audio signal is separated from the grounded shield. If electromagnetic noise is introduced into the balanced cable, it should be of equal intensity in both wires, and will be canceled out since a balanced signal is opposite polarity for the two lines.

For short runs in a home situation, it probably won't make a big difference as long at the cable is wired correctly. You're talking about runs of a few feet, not 50 meters or more.

The key difference in the guitar vs line inputs is going to be in voltage handling and impedance matching. Since the Neve is putting out a very hefty signal (between 775mV and 1.2V for 0dB) with headroom of up to about 10V. it can overload the guitar input, which is designed to handle pickup output voltages of anywhere from about 25mV to a max of about 5-600mV, depending on the pickup and how hard the player is strumming. A line level input should be designed to handle the larger voltage swing. The input impedance for line inputs is probably going to be in the neighborhood of 10K, whereas the typical guitar input will be in the realm of 1 MOhm.
 
You wont have damaged anything, so don’t worry. Sadly, this balanced and unbalanced thing is often really badly understood. We constantly take balanced outputs and short one of the pin 2 and 3 connections to pin 1 to do it. A dead short circuit, and it’s been a danger free process since balanced connections were invented. It works. Technically there are a few odd things that happen. Balanced cable has a screen, and the two inner conductors. If you use this type of cable for unbalanced connections, you could simply ignore one of those conductors and cut it off each end. Or you could leave it unconnected one end and at the other connect it to pin 1. Or, you could connect it at both ends. All three would work. All that changes is capacitance, which on short runs with decent cable is unlikely to be noticed. Many years back at college we tried this on a 100m drum of mic cable. On line and mic levels it wasn’t possible to tell a difference apart from a small amount of top end loss, but the very high impedance of guitars made it useless for them, and connecting or not connecting the inner core to pin 1 made a difference we could hear, but for the life of me after twenty years I can’t remember if it was better with, or without the inner core. Dave may know.

what I do know is that at +4dB the screen does very little, speaker cable works perfectly well with no screen and no hum over 3m, as I discovered when repairing an XLR to XLR that turned out to be an old speaker patch cable for stage monitors. It actually worked OK on a mic! Balanced audio is magic.

all the hums and buzzes we get seem nowadays to be traced back to noise current flowing between equipment in the ground of a cable and getting onto the audio, NOT the noise in the ether, getting through a screen.
we used to insist in contract riders that all audio cables had to cross lighting cables at right angles to reduce interference, and the. We started insisting lighting DMX data cables must not run alongside audio cables. Now it’s common for audio, data and even mains power to be in a single multi core.

we use ground isolated equipment, connected to grounded equipment willy nilly now, with everybody deliberately or accidentally connecting everything. The result is hums, buzzes and weird stuff and after hours or days the culprit is a ten dollar noisy power supply our balanced and unbalanced connections have Spread throughout the system.
with balanced outputs like in the Neve preamp, the best advice could be really simply. It has a proper balanced output that is floating, unreferenced to ground, so to connect to an unbalanced interface, maybe the simplest solution is to connect the interface ground to pin 2 of the Neve and the interface tip to pin 3 of the Neve. Totally ignore the ground/screen that end going to pin 1. If you like experimenting, include a little loop of cable from pin 2 to pin 1, and if you hear hum, cut it!

screens should be for screening, but they’re a free ride for noise hitching a lift.
 
You will not have harmed anything.

Get the a balanced cable and plug the output of the neve into a line input of the Yamaha as that is how it is meant to be connected.

Other connections may or may not work, but there is no reason not to do it the way it was intended.
 
What's the bet then that it's actually feeding through a pad into the mic preamp - that's a good way to make noise figures worse - lots of voltage, then throw most away and amplify it again. Another reason to think sonic purity wasn't on their mind when they designed that 'mixer'.
 
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