Audio interface for electric guitar: how to connect pedals, amp and PC without noise

Connecting electric guitar, pedalboard, amp and computer to an audio interface sounds simple until the problems start: hum, buzz, ground loops, digital clipping, unstable volume.

With a few key concepts you can build a setup that is clean, quiet and repeatable, both for recording and silent practice.

In this guide we’ll cover:

• the difference between instrument, line, mic and speaker levels;
• how to connect pedalboard → interface correctly;
• how to integrate a real amp + interface (with mic or dedicated outputs);
• how to avoid typical noise and hum when guitar meets computer.

To explore some options on Muviber, you can start from:

• audio interfaces for guitar and home studio
• guitar pedals and pedalboards
• load boxes and IR loaders

1. Understanding signal types: instrument, line, mic, speaker

Before plugging anything into your interface you need to know what kind of signal you’re dealing with.

• Instrument level The signal from your guitar or an unbalanced pedalboard output. Weak, high impedance. It belongs in an Instrument/Hi‑Z input.

• Line level Stronger, low‑impedance signal from synths, amp line outs, rack gear. It goes into a line input on your interface.

• Mic level Very low‑level signal from microphones (e.g. SM57 in front of a cab). It needs an XLR mic input with preamp.

• Speaker level The high‑power signal from an amp’s speaker output to a cabinet. Never plug this directly into an audio interface – it’s too powerful and can damage it.

Golden rule: speaker outs only go to cabinets or proper load boxes, never to an interface input.

2. Connecting the pedalboard straight into the audio interface

Common scenario: you want to use your pedalboard (drive, delay, reverb, modulation) and simulate amp/cab inside the computer.

2.1 Basic chain

1. Guitar → Pedalboard (input)
2. Pedalboard (output) → Instrument/Hi‑Z input on the interface
3. Interface outputs → monitors or headphones
4. In your DAW: amp + cab simulation (or IR loader).

2.2 Things to check to avoid noise

• Use a proper Hi‑Z input if the pedalboard output is instrument level.

• Start with the pedalboard’s output around halfway and set interface gain so levels stay in the green/yellow zone, never red.

• If noise is excessive, check:

  • the pedal power supply (isolated outputs are better);
  • cable length and condition;
  • gain pedals left always on.

3. Using a real amp with a microphone and audio interface

If you want your own amp and cab tone, the classic solution is to mic the speaker.

3.1 Typical chain

1. Guitar → pedalboard → amp input
2. Cab connected properly to the amp’s speaker out
3. Mic (e.g. SM57) in front of the speaker → XLR mic input on the interface
4. Interface → computer → DAW

3.2 Basic mic placement

• Start a few centimetres off the grille;
• aim at the area between dust cap and cone edge;
• move slightly towards the centre (brighter) or edge (softer) to taste.

3.3 Avoiding noise in this setup

• Use a decent balanced XLR cable.

• If you hear 50/60 Hz hum:

  • plug amp and interface into the same power strip if possible;
  • avoid sketchy adapters and loose power sockets.

• Keep audio cables away from power bricks and transformers.

4. Using amp line outs, sends and emulated outputs

Many modern amps provide outputs you can feed straight into the interface without micing a cab.

4.1 Line out / recording out

• Usually a line‑level output, sometimes with built‑in cab sim.
• Connect it to a line input on the interface (not Hi‑Z).

If there’s no cab sim, use an IR loader or cab sim plugin in your DAW – otherwise the sound will be harsh and fizzy.

4.2 FX loop send

• Some players use the FX send as a line out.
• Again, this is usually line level → line input on the interface.
• Often you’re only capturing the preamp section, not the power amp + speaker, so an IR is still recommended.

4.3 Emulated / cab sim outputs

• Many amps and pedalboards now offer cab‑sim outputs.
• These can go straight into a line input and monitored without extra plugins if you like the built‑in sound.

5. Real amp, silent recording: load boxes and IR loaders

If you want to use a tube amp but record silently on headphones, you’ll need a load box or attenuator with line out.

Typical chain:

1. Amp → load box / attenuator connected to the speaker out (instead of a cab);
2. Load box line out → line input on the interface;
3. In DAW: cab IR or cab sim plugin;
4. Listen on monitors/headphones.

Always follow the manufacturer’s instructions for impedance and power handling to avoid damaging your amp.

6. Avoiding hum, buzz and ground loops

One of the most annoying problems when you connect amp, pedals and computer is the ground loop.

6.1 Good practices

• Plug your PC, interface and amp into the same power strip whenever possible.
• Use balanced cables (TRS or XLR) for all line/mic connections.
• Avoid having the amp connected to multiple systems (PA + interface + other gear) on different power circuits without proper planning.

6.2 DI boxes and ground lift

If the hum is really bad, a DI box with ground lift can:

• convert the signal to balanced;
• safely break the ground loop.

Never remove safety earth pins or use dangerous adapters to "solve" hum issues. Safety always comes first.

6.3 Pedal power

A lot of hiss comes from cheap power supplies:

• use a decent pedal power unit with isolated outputs;
• avoid endless daisy chains mixing analog and digital pedals.

7. Gain staging: no clipping, no tiny signals

For a clean, usable recording:

1. Set pedalboard/amp output to a healthy level (not minimum, not maxed).
2. Adjust interface input gain so peaks hit the green/yellow area, never red.
3. Check DAW meters: again, no red, no squared‑off peaks.

Analog distortion (drive/fuzz/amp crunch) = part of the tone. Digital clipping in interface/DAW = harsh and unpleasant, best avoided.

FAQ – Audio interface for electric guitar

Can I plug the amp’s speaker output directly into the audio interface?

No. Speaker outs carry high‑power signals meant only for cabinets or load boxes. Plugging them into an interface can damage the interface and potentially the amp. Always use a mic on the cab or a load box with line out.

Should I use the line input or instrument input on the interface?

It depends on the source:

• Guitar or basic pedalboard → Instrument/Hi‑Z input.
• Amp line out, load box, multi‑FX, modeler → line input.
• Mic in front of the cab → mic input (XLR).

Why do I get loud hum when the amp and PC are both connected?

That’s often a ground loop between PC, interface and amp. Try:

• plugging everything into the same power strip;
• using balanced cables where possible;
• inserting a DI box with ground lift at the right point in the chain.

Is it better to go direct with the pedalboard or mic the amp?

It depends on context:

• direct board + cab sim = convenience, silence, consistent results;
• mic’d amp = more character and real‑world feel, but requires volume and a suitable room.

Many players use both approaches depending on the situation.

Can I record my tube amp at night on headphones?

Yes, but you need the right gear:

• a load box or attenuator with line out between amp and (optional) cab;
• an audio interface with line input;
• a cab IR or cab sim plugin in your DAW.

Never power up a tube amp without a proper load (cab or load box) connected.