Why does my high-gain rig hiss, and where does the noise gate go?

Name the noise

Turn the guitar volume to zero, then pull the cable out of the amp. What stays tells you where the noise lives.

Hum or buzz that drops with the guitar volume at zero

It comes in through the pickups. Single coils pick up hum from lights, dimmers and screens, and high gain turns it up.

Hiss that stays with the guitar volume at zero

Your pedals or the amp. Pull the cable out of the amp input: if the hiss stops, it comes from the board.

Hiss with nothing plugged into the amp

The amp’s own preamp noise. Some is normal on a high-gain channel, and a gate in the effects loop handles it.

Hum that starts when you connect a second device

A ground loop. The pedalboard hum guide walks through it.

A squeal that builds near the amp

Feedback. Step back or turn away from the amp, and mute the strings when you stop. A pickup that squeals with the strings muted may be microphonic; a tech can wax-pot it.

Checks, cheapest first

1. 01Turn the guitar volume to zeroNoise that drops comes in through the pickups or the cable. Noise that stays comes from your pedals or the amp. This one test tells you which half of the rig to work on.
2. 02Face away from lights and screensSingle-coil pickups pick up hum from dimmers, LED and fluorescent lights, screens and power cables, and high gain makes it loud. Turn to face a different direction and listen for the hum to drop. Humbuckers are built to cancel this kind of hum.
3. 03Back off the gainEvery gain stage amplifies the noise of the stages before it, so a high-gain pedal into a high-gain channel multiplies the hiss. Lower the amp’s gain or the pedal’s until the hiss drops and palm mutes still sound tight.
4. 04Pull the cable out of the ampTurn the amp down, pull the cable out of its input, then turn the amp back up. A steady hiss on a high-gain channel is normal. A loud hum, a crackle, or hiss that got worse suddenly points at the amp, often a tube. Book a tech, and do not open a tube amp yourself: its capacitors hold dangerous voltage even when it is unplugged.
5. 05Clean up the powerPlug the whole rig into one outlet or power strip, away from lighting dimmers and other heavy loads where you can. Hum that starts when you connect a second powered device, like a second amp, a DI box or a laptop over USB, is a ground loop, and the pedalboard hum guide covers it. Never remove or tape over the ground pin on a mains plug: that pin protects you from electric shock.
6. 06Gate in front of the ampFor hiss and hum from the guitar and pedals, put the gate after your drive pedals and before the amp input. Keep it ahead of any delay or reverb so it does not cut their tails short. It mutes that noise before the amp amplifies it, and it cannot touch hiss the amp makes on its own, because that starts after the gate.
7. 07Gate in the effects loopFor hiss from the amp’s preamp, run the amp’s loop send into the gate and the gate’s output back to the loop return. Now it mutes everything the preamp makes. In the loop the gate hears a heavily distorted signal with little difference between loud and quiet, so it can cut sustain short or chatter. The 4-cable method below solves that.
8. 08Set the threshold and release by earTurn the threshold up until the hiss is gone with your hands off the strings. Then play tight palm-muted chugs and a held chord, and back the threshold down until notes stop choking: no clipped attacks, no tails cut short. Set the release short for tight stops and longer so held notes fade naturally.

The 4-cable method, step by step

A gate with its own send and return jacks can work in front of the amp and in the loop at once. Its key, the signal it listens to, is the clean guitar at its input, where loud and quiet are easy to tell apart. What it mutes is the amp’s preamp output as it passes through the loop. Your amp needs an effects loop for this.

Cable 1

Guitar into the gate’s input. This is the clean signal the gate listens to.

Cable 2

The gate’s send, through your drive pedals, into the amp’s input.

Cable 3

The amp’s effects loop send into the gate’s return.

Cable 4

The gate’s output into the amp’s effects loop return.

On a gate with two gated paths, one quiets the pedals in front of the amp and the other quiets the preamp in the loop, and both follow the clean guitar at the input. Jack names differ from gate to gate, so match each cable to the labels in your gate’s manual and label the four cables before you plug in.

Why a TS-style boost tightens the low end

Many high-gain players run a TS-style overdrive in front of the amp with its gain low and its level high. The circuit boosts the mids far more than the lows, so the amp’s preamp receives less bass relative to the mids. Less bass going into the distortion means less low-end flub: palm mutes sound tighter and chords stay clearer.

The boost also pushes the preamp harder, so you can often lower the amp’s gain for the same saturation, and less gain means less hiss. Keep the boost in front of the amp’s input with your other drive pedals.

Common mistakes

• Setting the threshold so high that palm mutes and note tails get chopped. Use the lowest setting that still mutes the hiss.
• Using a gate to hide hum from a ground loop or bad power. The gate mutes between notes, and the hum is still under every chord. Fix the source.
• Putting the gate in front of the amp to quiet the amp’s own hiss. The amp makes that hiss after the gate, so the gate never hears it. Use the loop or the 4-cable method.
• Running a high-gain pedal into a high-gain channel with both turned all the way up. Each stage amplifies the noise of the one before.
• Putting delay or reverb ahead of the gate, so it chops off the tails.
• Mixing up send and return when wiring the 4-cable method. Label the cables and follow the gate’s manual.
• Lifting the safety ground on a mains plug to stop hum. That pin protects you from electric shock.

Words used here

Noise gate

A pedal or circuit that mutes your signal when it falls below a set level, hiding hiss and hum between notes.

Threshold

The level that opens the gate. Signal above it passes through; below it, the gate closes and mutes.

Release

How quickly the gate closes once your signal falls below the threshold. Some gates call it decay.

Effects loop (FX loop)

Send and return jacks on an amp that place pedals between its preamp and its power amp, after the amp’s own distortion.

4-cable method

Wiring a gate or multi-effects unit that has its own send and return to an amp’s effects loop with four cables, so part of it works in front of the amp and part works in the loop.

Key

The signal a gate listens to when it decides to open. In the 4-cable method the key is the clean guitar, while the gate mutes the preamp output.

Preamp

The amp’s first stage, where a high-gain amp makes most of its distortion and most of its hiss.

Chatter

A gate flickering open and shut while a note hovers near the threshold.

TS-style overdrive

An overdrive built on the classic Tube Screamer circuit, which boosts the mids far more than the lows.

Single-coil pickup

A pickup with one coil of wire. Bright and clear, and it picks up hum from nearby electrical gear.

Tools for this

• The BoardLay out your chain in order before you decide where the gate goes.→
• Power plannerCheck every pedal gets enough current on the right output.→
• Power suppliesFind a supply with isolated outputs so a noisy pedal stays out of the rest of the board.→

Related guides

• How do I stop my pedalboard humming?Hum, buzz, ground loops and digital whine, cheapest check first.→
• What order do guitar pedals go in?Tuner to reverb, slot by slot, with the reason behind each one.→
• What string gauges do I need for a 7-string, 8-string or drop tuning?Heavier gauges for lower tunings, why scale length matters, and the setup after.→