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Question about my interface inputs...


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I've got 2 XLR/TRS inputs and 2 1/4 inputs on the back of my interface. My manual tells me that the XLR/TRS inputs take a balanced line/XLR cable (obviously). The 2 1/4 inch plugs also take a balanced input, but the manual mentions that it also takes unbalanced lines. The 2 1/4 inch plugs say that it's best used for "instruments with line level signals (10-dB to 4dB)."

 

So here's my two questions: 1.) What is an instrument with a "line level signal" The manual mentions "synthesizers, drum machines, and effects processors" as an example. 2.) The main instrument I want to record through the interface is a guitar, so I'm guessing it would work best plugged into one of the XLR/TRS combo jacks, however, it mentions nothing about accepting unbalanced cables, so will I have to plug the guitar into the interface with a TRS cable? I'm a little confused.

 

Thanks for your help.

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I believe a guitar amplifier is a line-level signal, so if you've an amp you can plug that into a line input. You would need some way of amplifying the signal from the guitar (eg the amp, or a DI box), I dont think you would get much sound plugging guitar straight into the line input.

 

LIne level I guess means a signal that has already been amplified. Synths will have onboard methods of making the sound loud enough for that level. Guitars need something else.

 

I think the difference between balanced and unbalanced cables is that balanced is isolated so that it can;t pick up noise from surrounding sources, whereas unbalanced is not isolated so could pick up noise (from another electrical source). The signals running down the cables are effectively the same though.

 

My knowledge on this is pretty basic so perhaps someone else can advise further.

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I believe a guitar amplifier is a line-level signal, so if you've an amp you can plug that into a line input. You would need some way of amplifying the signal from the guitar (eg the amp, or a DI box), I dont think you would get much sound plugging guitar straight into the line input.

 

LIne level I guess means a signal that has already been amplified. Synths will have onboard methods of making the sound loud enough for that level. Guitars need something else.

 

I think the difference between balanced and unbalanced cables is that balanced is isolated so that it can;t pick up noise from surrounding sources, whereas unbalanced is not isolated so could pick up noise (from another electrical source). The signals running down the cables are effectively the same though.

 

My knowledge on this is pretty basic so perhaps someone else can advise further.

 

Well the XLR/TRS combo jacks have preamps, if that help?

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It's all about impedance, which is resistance on a circuit, and that those values are the same between components.

Guitar signals are high impedance, and that's what a guitar amp expects. If amps have a headphone out or simulated output, then it lowers the impedance and becomes line level.

Mic signals are low impedance. The output of a mic pre is line level.

If you have a combo jack, that doesn't necessarily mean you have a guitar or bass instrument input, which is high impedance. Check the interface manual to see that it accepts a guitar signal. There's sometimes a switch for instrument inputs.

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It's all about impedance, which is resistance on a circuit, and that those values are the same between components.

Guitar signals are high impedance, and that's what a guitar amp expects. If amps have a headphone out or simulated output, then it lowers the impedance and becomes line level.

Mic signals are low impedance. The output of a mic pre is line level.

If you have a combo jack, that doesn't necessarily mean you have a guitar or bass instrument input, which is high impedance. Check the interface manual to see that it accepts a guitar signal. There's sometimes a switch for instrument inputs.

 

There's no way to switch the input to an "instrument" mode or anything like that. What if I plugged it into one of 1/4 Line in's? Or would I be better off running my guitar through a DI box and plugging into one of the XLR inputs? I'm getting a little confused...all I want to do is plug my guitar straight into my interface.

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Some interfaces don't have a switch, it changes impedance automatically. Did you check the manual of your interface?

Doesn't the Lambda have the instrument input in the front?

Just try the combo input with your guitar and see if you get signal into Logic.

If not, then get a DI box.

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