Guitar straight into the audio interface?

Plugging the guitar straight into the ‘instrument input’ of an external audio interface can easily cause some nasty clipping. The input signal is too powerful and needs to be attenuated. We are left with one problem: we cannot reduce the power output of our guitar nor can we reduce the input gain of our audio interface.

Many (mostly the cheaper) audio interfaces don’t like too much input gain coming in from the guitar. This happens especially with the bridge humbuckers. They can produce a huge amount of power. Now, if there was a pad switch available you would attenuate the input signal by a few decibels. But many audio interfaces and sound cards don’t have that. Some allow you to switch their inputs from instrument to line level. But this lowers the input impedance and an electric guitar with its passive pickups expects a high impedance input otherwise it will sound sort of dead and flat. It might work with a guitar that has active electronics built in (you know you have one when there’s a battery in your guitar).

The simplest solution:

  • Use a D.I.-box. You plug the guitar directly into the D.I.-box and from there you use an XLR cable to connect to the audio interface. When using the XLR input the audio interface should automatically switch to microphone level which is perfect.
    I use a passive Palmer D.I. It’s a good quality make and doesn’t alter the sound.
Palmer D.I. box
Palmer D.I. box

Other solutions that could work:

  • Use a different audio interface. Sounds silly but you might have some other device like a floor effects processor that comes with a USB port. Many of those have a sound card built in. Connect the USB to the computer and you have another input/output path for your signal. I made some good experiences with a Line 6 HD500. I set everything to neutral, I don’t use any virtual amplifier and so the plain guitar signal goes from the HD500 into my computer. The Line 6 has no problems with high input signals at all. A little drawback often seen then is that the signal has a higher latency than even some of the cheapest audio devices.

One solution that definitely doesn’t work:

  • Turn the volume down on the guitar. This will change the sound of the guitar considerably to a thinner sound. Use the volume for sound control, not for volume control.


What’s you experience with audio-interfaces from Focusrite, Motu, Apogee, Presonus, Behringer, Tascam, etc?

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