How to use PedalSpice

The Editor

Select a part on the left. You can drag it to the grid in the middle and work on your circuit. Frequency plots and results are on the right.

To make either side bigger or smaller, drag the line between them. The File, Edit, and View menus are at the top. The zoom buttons are at the bottom right of the grid.

Power

Pick 9V or 18V from the dropdown at the top.

Your input signal

Right-click the input source to pick what feeds your circuit: Ideal source (a clean test tone), Humbucker, or Single coil. To change how strong the signal is, double-click the input source and change the number in the Signal level box.

Zooming and the View menu

Use the buttons at the bottom right of the grid to zoom in, zoom out, or fit your whole circuit on the screen. The View menu has the same buttons. There, the fit button is called Zoom to Fit.

The View menu also turns on Voltages, Impedances, Dark, Hide grid, and Full screen. Once dark mode is on, the Dark button says Light, so you can switch back. Hiding the grid dots does not change how your parts line up.

How to use, at the bottom of the View menu, opens this page in a new tab. Your circuit stays right where you left it.

Placing and changing parts

Placing a part

1. Drag a part from the left onto the grid.
2. To pick a different model, like another transistor or op amp, right-click the part on the left first.
3. To place the same part over and over, hold Shift and click the part on the left. Keep holding Shift and click the grid each place you want one. Let go of Shift, or press Escape, when you are done.
4. To place grounds, press G or click the Ground tile, then click the grid each place you want one. Press Escape when you are done.

Moving parts

Drag a part to move it. To move several parts together, drag a box around them, then drag them.

To pick parts one at a time, hold Shift and click each one. Shift-click a part again to leave it out.

To select everything, press Command A on a Mac or Ctrl A on Windows. Then you can move, copy, or cut it all at once.

To move around your schematic, hold Command and drag on a Mac, or hold Ctrl and drag on Windows.

Changing a part

Open a part to change its value or its name. Press Enter to keep the change, or press Escape to cancel. To delete the part, click the trash can in that box.

You can give a part your own name, like R10. If another part already has that name, PedalSpice picks a new one and tells you.

To renumber your parts, choose Rename part labels from the Edit menu. It numbers them top to bottom, and left to right across each row. It only changes the names PedalSpice gave them. Names you typed yourself stay the same. One undo brings the old numbers back.

To change several parts at once, select them, open one, and change its value. Every selected part of that kind gets the new value.

Turning and flipping a part

Select one part, then press a key or pick the same command from the Edit menu.

R turns the part. H flips it left to right. V flips it top to bottom. F moves its label to the other side.

When you select one pot, H is called Mirror pot, and it swaps the pot's two outer legs. On a pot lying flat, H swaps legs 1 and 3. On a pot standing up, V does.

The Flip button in the Knobs & switches panel is different. It flips a switch, not a part.

Notes

Add a text note anywhere and drag it where you want it. Your notes show up on the PDF when you export it.

Wiring

1. Press W or click the Wire tool.
2. Click where you want the wire to start.
3. Click at each corner.
4. Click where you want it to end.

The Wire tool stays on, so you can keep drawing wires.

When your mouse gets close to a part, its connection points show up. Click near a leg to connect to it. To join two wires, end one wire on the other one.

To put a part into a wire, drop it so its legs sit on the wire. A green glow shows where it will connect. If a part with two legs has both legs on the wire, PedalSpice cuts the wire and puts the part in. A red dashed line shows the piece of wire that gets cut out.

Click a wire to select it. If you delete a part, its wires stay where they were, with open ends.

Moving a wire

Press on a piece of wire and drag it. A flat piece moves up and down. A standing piece moves left and right. It moves half a grid square at a time, and both ends stay hooked to their legs. One undo puts it back.

To go back to the path PedalSpice drew, drag the wire back to where it started.

Wires that cross

When two wires cross without connecting, the flat wire shows a small bump. A dot means the wires are connected. You don't have to set anything for this.

Running your circuit

Press the orange Run button. If the button is pulsing, you changed something since your last run.

After a good run, turn the knobs and watch the plot change.

When it won't run

PedalSpice tells you what's wrong and lights up the part. Fix it and press Run again. Smaller problems show a yellow badge, and they don't stop the run.

The most common problems are a wire across both legs of a part, and a part or leg that isn't hooked to anything. Other problems are having no ground symbol, and an op amp with nothing giving it a steady starting voltage.

A pot with a loose leg

If one outer leg of a pot isn't hooked to anything, that's fine. The pot works as a variable resistor between the middle leg and the other outer leg. PedalSpice warns you about loose legs on other parts, but not on pots or switches.

Reading the plot

The main plot shows how loud your circuit is at each pitch, from low to high. Click it to make it bigger. Move your mouse across it to read the frequency and level of every curve at that spot.

To see the shape of your signal over time, look at the waveform view. You can show the input signal on top of it to compare the two.

Voltages and impedances

To see the steady voltage at each point in your circuit, turn on Voltages in the View menu. Your knobs still work while it's on.

To see how much your circuit resists the signal going in and coming out, turn on Impedances in the View menu. The knobs and switches are greyed out while it's on.

To turn either one off, choose it again.

Setting a JFET's bias

1. Open the JFET.
2. Type the voltage you want at its drain leg into the Set bias box.
3. Press Enter.

PedalSpice turns the trim pot to get as close to that voltage as it can. If it can't get there, it tells you.

OTA chips

The LM13700 and CA3080 chips are included. They are OTA (operational transconductance amplifier) chips, and they need a small steady current to work.

Most of the time, you feed that current from the V+ power line through a resistor to the chip's bias pin. If that pin isn't hooked up, PedalSpice tells you and won't run.

Trying values, sweeps, and snapshots

Trying several values at once

1. Open a resistor or capacitor.
2. In the Try several values box, type 2 to 12 values with commas between them, like 1k, 2.2k, 4.7k.
3. Press Run. You get one curve for each value.

You can also step a pot through 11 positions with one click, and each position gets its own curve. You can sweep two parts at once, for up to 12 curves in all.

Turning knobs during a sweep

With sweep curves on the screen, turn a knob or press Flip on a switch. A moment after you stop, every sweep curve redraws.

Snapshots stay the way they are. Changing, adding, or removing a part or a wire clears the sweep. So does Remove sweep.

Snapshots

Click Snapshot to freeze the curve you have now as a dashed line. Then change your circuit, and the new curve draws on top so you can compare them.

You can rename or delete a snapshot. Each one is named with the knob and switch positions it was taken at. Snapshots are not saved with your circuit.

Pots

Pick the taper you would buy: Audio, Linear, Reverse audio, or W. The taper is how the pot's resistance changes as you turn it. W only comes in 20k.

Use Trim for a set-and-forget adjustment, the kind you would set once with a screwdriver.

Double-click a knob to set it to 12 o'clock. One undo puts it back.

A dual-gang pot is two pots on one shaft. PedalSpice places both, and one knob turns them together.

The Free plan lets you use three pots. A dual-gang pot counts as one.

Switches

Right-click the switch tile on the left and pick SPDT, DPDT, or 3PDT. The name tells you how many circuits the switch changes at once.

You can also open the switch and change it in the Type box. The same box has Up position and Down position, the two settings of the switch.

To flip a switch, press its Flip button in the Knobs & switches panel. Clicking the switch on your drawing only selects it. After a good run, the plot redraws a moment after you flip.

Circuit Blocks

A circuit block is a ready-made piece of a circuit. A gain stage makes the signal louder. A tone stack shapes the bass and treble. There are six gain stages and six tone stacks.

1. Click Circuit Blocks in the top bar.
2. Open a heading, like Gain Stages or Passive Tone Stacks. Opening one heading closes the others.
3. Click the block you want. The connection dots where it can go pulse blue.
4. Click a pulsing dot. The block drops into your signal path there, already wired. If there isn't room, everything after that spot slides over to make room.

To place a block by itself, not hooked to anything, click an empty spot instead. Press Escape to cancel. One undo removes the block.

Once a block is placed, its parts are regular parts. There is no group or ungroup. To move them together, drag a box around them, Shift-click them, or choose Select all, then drag.

Circuit Blocks come with Pro and the free trial. On the Free plan they are greyed out.

Parts a block hides

When two blocks connect, some parts aren't needed anymore, like a doubled output part. PedalSpice hides them and leaves them out of the simulation. Pull the blocks apart and those parts come back. Once you change parts inside a block, PedalSpice stops hiding parts from it.

My Blocks

My Blocks is the first heading in the Circuit Blocks menu. It comes with Pro and the free trial. You can keep up to 20.

There are three ways to save a block there. Tick Save to My Blocks in a calculator. Or draw the circuit you want as a block, with nothing else on the screen, wire it to the guitar jack and the amp jack, press Run, and choose Save drawing as a block. Or choose Import a circuit file as a block and pick a circuit file you exported. Either way, the guitar jack and amp jack mark where the signal comes in and goes out, and they are not part of the block.

To place one, click its name, then click a pulsing dot or an empty spot.

To delete one, click Delete. It asks Delete?, and you pick Yes or No. You can't rename a saved block.

Circuit Calculators

1. Click Circuit Calculators in the top bar, next to Starter Circuits and Circuit Blocks.
2. Pick one of the 16 calculators and set the values.
3. Press the button that starts with Send to. The RC Filter (a resistor and a capacitor working as a filter) has two of them. One keeps the low pitches (Low-Pass), and one keeps the high pitches (High-Pass).
4. Click a pulsing dot or an empty spot to place the block.

To keep the block in My Blocks too, tick Save to My Blocks. It saves once the block is on the grid.

Circuit Calculators come with Pro and the free trial. On the Free plan they are greyed out.

Parts list

Choose Parts list in the File menu. A box opens that lists every part in your circuit. Every plan can open it.

The columns are Ref (the part's name), Component, Qty (how many), and Where to buy. Each store has a Buy at link. A part without a link says no link yet.

To print the list, press Save as PDF in that box. The links still work in the PDF. Save as PDF comes with Pro and the free trial.

To get a spreadsheet of your parts, choose Export BOM (bill of materials) in the File menu. It comes with Pro and the free trial. After it downloads, a box opens with a Request it here link, where you can ask us to add a part.

On a phone, the Show Parts button opens the list of parts you can place. It is not this list.

Hearing your circuit

1. Pick a Source. Choose one of the eight guitar clips that come with it, or drag in your own audio. Your own clip can be up to eight seconds long. A longer clip won't load.
2. To hear the clip by itself, with no circuit and no amp, press Preview.
3. Pick an Amp: Direct, British 45, British Chime, or American Clean. Direct means no amp. To use your own amp, press Upload your own amp (.nam file). A .nam file is a recording of an amp's sound.
4. Press the orange Render bar. It makes the sound of your circuit. An eight-second clip takes about 25 to 30 seconds.
5. Click Play result to listen. Turn on Loop to hear it over and over.
6. To save it as a sound file, click Download WAV.

If you change your circuit, the sound is out of date. Press Render again.

Saving and exporting

Your circuits are saved in your PedalSpice account, so they're there on any computer you sign in from.

To save, choose Save in the File menu. The first time, it asks you for a name.

To save a new version without changing the one you have, choose Save a Copy and give it a new name.

To change a saved circuit's name, choose Rename in the File menu, or press Rename next to it in My Circuits.

To open a circuit, choose Open. It takes you to your My Circuits page. Click Open on the circuit you want. To remove one, click Delete, and it asks you to make sure.

If you have changes you haven't saved, PedalSpice asks Do you want to save? before you sign out, start over, or open a starter circuit.

PedalSpice also keeps a backup copy of your work as you go, so refreshing the page won't lose anything. That backup never changes a circuit you saved.

Circuit files on your computer

To save a circuit file to your computer, choose Export circuit in the File menu. To open one, choose Import circuit.

Other exports

Export PDF makes a schematic you can print. Export netlist saves your circuit as a text list of its parts and connections that other simulator programs can read.

Export for KiCad (beta) saves your circuit for KiCad, a free program for designing circuit boards, with each part's board outline already picked.

Starter circuits

Starter Circuits are complete circuits that already work. Click one, press Run, and start changing things.

Start over and Sign out

To clear everything and start fresh, choose Start over in the File menu. It asks you to make sure first. Sign out is in the File menu, right below Start over.

Sharing and the library

Share link

Choose Share link in the File menu. A box opens with a web link that holds your circuit. Press Copy link to copy it. Every plan can make one.

Anyone with the link can see your schematic and press Run. If you pressed Run before you shared it, they see your plot too. They don't need an account.

Make public

To put a circuit in the library, choose Make public in the File menu. The same button is on your My Circuits page.

You have to save the circuit first. Until then, the button is greyed out. New circuits start out private. To take a circuit back out of the library, choose Make private.

The library lists circuits 50 at a time. It doesn't have a search. To open it, click Circuit library at the bottom of this page.

Anyone, signed in or not, can open a circuit in the library and press Run. Nobody can change someone else's circuit.

Reviews

You can leave one review per account on the Reviews page. It shows up after we approve it.

Touch screens

PedalSpice works on touch screens, however some features may not work completely. We are currently working on a separate version made just for them.

On a phone, the schematic is on top and the plots are below it.

To place a part, drag it sideways out of the list.

To move a part, drag it with one finger. To move around the drawing, use two fingers. Pinch to zoom.

To open a part, tap it twice.

To draw a wire, tap the Wire tool, then tap each point.

To place grounds, tap the Ground tile to turn the ground tool on, then tap the grid. Tap the tile again to turn it off.

To turn a knob, drag it.

Press and hold works like a right-click on the parts list and on the input source. On a pot in your drawing, press and hold only works if your browser treats it as a right-click.

Plans

Every new account gets Pro free for the first week. See the Pricing page for prices.

To change or cancel a paid plan, choose Manage plan in the File menu.

On Free, you can still save the sound file after a render. If your plan drops to Free, nothing already on your sheet is removed.

Shortcut keys

• R turns the selected part.
• H flips it left to right.
• V flips it top to bottom.
• F moves its label to the other side.
• W turns the Wire tool on or off.
• G turns the ground tool on or off.
• Space bar fits your whole circuit on the screen.
• Shift and click on the grid adds a part or wire to your selection, or takes it back out.
• Arrow keys move the selected part one grid step.
• Delete or Backspace deletes what you selected.
• Command X, C, and V cut, copy, and paste (Ctrl on Windows). Paste again for another copy.
• Command D makes a copy of what you selected (Ctrl D on Windows).
• Option and drag pulls out a copy (Alt and drag on Windows).
• Command A selects everything (Ctrl A on Windows).
• Command Z undoes. Command Shift Z redoes (Ctrl Y on Windows).

The Edit menu shows the shortcut next to each command that has one. It always says Cmd, so on Windows, read Cmd as Ctrl.

Suggest a feature

Click Suggest a feature in the top bar. It opens our form in a new tab. Every plan has it.