Handbook
The Amp Handbook
The built-in amp, loading NAM captures, and using your own cab impulse responses.
RigShed gives you three ways to get an amp sound: the one built into the app, a capture of a real amp that somebody measured, and your own cabinet impulse response on top of either. This explains what each one is actually doing, so you can tell which knob is going to fix the problem you’ve got.
Built-in amp · NAM captures · cab IRs · free tier holds three of each
The built-in amp
The amp that’s there when you open the app is RigShed’s own model of a blackface-style valve combo into a 12-inch open-back cabinet. It is not a recording and not a capture — it’s a circuit model, built from the same stages the real thing has, in the same order.
That order is the point. Signal goes in, through the coupling stages, through the tone stack, into the valve stage, and out through the speaker. The tone stack sits before the valve stage and presence sits after it, because that’s where they sit on the circuit.
Which means the bass knob is a gain control
Turn the bass up and you are not just adding low end — you are pushing more signal into the valve stage, so the amp distorts earlier and harder. That is how the real circuit behaves and it is why a bass-heavy setting sounds thicker and dirtier rather than just boomier.
If you want more low end without more breakup, pull the drive back as you turn the bass up.
Noon is the amp
Every tone control is centred. With bass, mid, treble and presence all at noon, you are hearing the amp exactly as it was modelled — the controls move either side of that rather than building a sound up from flat.
Drive works the same way. At noon it’s the modelled amp; below backs the valve stage off toward clean, above pushes it into breakup.
So if you have twisted everything and lost the plot, put the four tone controls and drive back to noon. That’s not a neutral setting, it’s the setting, and it’s a better starting point than anything flat.
Two things you’ll feel before you hear
Sag. Under sustained load the supply droops, so a hard-strummed chord compresses instead of just getting louder. It’s why the amp pushes back when you dig in, and why strumming harder past a certain point changes the texture rather than the volume.
Presence sits before the distortion. Hard playing drives the top end into compression harder than the mids, so the brightness backs off as you play harder and comes back as you ease up. That level-dependent loss of brightness is most of what separates a valve amp from an EQ curve, and it’s the reason the amp feels responsive to your right hand rather than just loud.
Neither has a control. They’re in the model.
Loading a capture
A capture is a profile of a real amp that somebody measured and shared as a
.nam file. Thousands are freely available online. Load one and RigShed plays
your guitar through it.
Open the capture browser and pick a file. Loading takes a moment — the model has to be read and prepared — and then the amp panel changes.
Why the knobs disappear
When a capture loads, the amp panel shows that amp’s face and two controls only: Level and Mix. This surprises people, so it’s worth being plain about why.
A capture is a snapshot of one amp with its knobs in one position. Whoever made it chose those settings before they measured it. There is no bass control inside the file to expose — the tone stack was set, and then the whole thing was captured as a single behaviour. Giving you a bass knob would mean bolting an EQ onto the outside and pretending it was the amp’s own, which is exactly the sort of thing this app doesn’t do.
So a capture gives you what it is:
| Control | What it does |
|---|---|
| Level | How loud the captured amp comes out |
| Mix | Blends the captured sound against your dry signal. Leave it up unless you’re deliberately parallel-blending |
If you want a different tone from a capture, the honest routes are a different capture, or the pedals in front of it — which is what you’d do with the real amp too.
Getting your tone back
The built-in amp is still there. Unload the capture and the full set of controls comes back. Nothing is lost by trying one.
Cab impulse responses
An impulse response is a measurement of a speaker cabinet in a room. Load a
.wav IR and it becomes the cabinet your amp plays through.
The IR replaces the speaker — it doesn’t stack on it
This is the one thing to understand. When you load a cab IR, RigShed switches its own speaker off and feeds the IR a raw power-amp signal instead.
Most software gets this wrong and leaves both in the chain, which puts two cone roll-offs and two resonances in series. The result is boxy, muffled, and no amount of EQ properly fixes it. You get the cab you chose, not two cabs.
Presence stays on either way, because presence is power-amp feedback rather than part of the speaker. That’s the correct place for it.
One consequence worth knowing
If you load an IR and the sound goes thin and fizzy, that’s not a fault — it’s what a power-amp feed sounds like through a cab that isn’t doing much. Try a different IR before you start reaching for EQ. IRs vary enormously in quality, and a bad one sounds bad through anything.
Working order
The three parts stack in a fixed order, so set them in that order:
- Pick your amp — built-in or a capture. This is the biggest decision and everything after it is a refinement.
- Pick your cabinet — the amp’s own speaker, or your IR. This changes the sound more than any tone control will.
- Then use the tone controls, if you’re on the built-in amp. Adjusting EQ before you’ve settled the cabinet means doing it twice.
- Then the pedals, which sit in front and drive the amp.
What the free tier holds
| Free | Pro | |
|---|---|---|
| Amp captures stored | 3 | Unlimited |
| Cab IRs stored | 3 | Unlimited |
| Saved presets | 3 | Unlimited |
The built-in amp, its cabinet and every tone control are free and stay free. The caps are on how many of your own files you keep loaded, not on whether the feature works.
If something seems wrong
| Symptom | Cause |
|---|---|
| Capture sounds quiet or thin next to the built-in amp | Captures are made at whatever level the maker chose. Use Level to match, and check Mix is fully up |
| Only two knobs on the amp | A capture is loaded. That’s all a capture has — unload it for the full set |
| Loaded an IR and it went boxy | Unlikely to be stacking, since the speaker switches off automatically. More often the IR itself, or an IR of a cab you don’t actually want |
| Amp distorts as soon as I turn the bass up | Working as designed — the tone stack drives the valve stage. Back the drive off |
| Playing harder gets darker, not louder | Also working as designed. That’s presence sitting before the distortion, plus sag |
| Can’t add another capture | Free tier holds three. Remove one, or go Pro |
| Brief pause when loading a capture | The model is being read and prepared. It happens once per load, not while you play |
All of this is in the app already
Nothing here is an add-on. What's free and what isn't.
Join the TestFlight beta — link pending