Using Falstad to Simulate Pedal Boards Before Building?

[raddad92]

Hello all,

First and foremost, forgive me for any questions that may be repetitive. I looked for previous threads and was unable to find any. Additionally, I am very new to circuitry and may have misconceptions on what I think should be happening, so please forgive me for my ignorance.

I was wondering if any of you have used Falstad to simulate boards before building them.

Circuit Simulator Applet

Currently, I am trying to build a Big Muff Pi. My build is based around the Green Russian, but some of the parts that are needed are not currently on hand (specifically, certain specific resistances and capacitors). I want to use Falstad with *similar* components that I have on hand to see if it would even work (since I lack the education to know how to do any of the math needed to figure it out without a tool like this). I recognize that this will likely change the sound, even if it works, but this is more for getting my feet wet on building pedals.

With that being said, one of the things that I'm having issues with is simulating the stomp switch on the circuit.



From my understanding, SW1,2, and 3 are indicating that they are connecting connecting to the Stomp switch. The problem that I'm having is making the simulation closely resemble the schematic above with the creation of a single simple on/off switch that only has two points of connection. The simulation has a few other switch options, but none of them seem to really replicate the actions of the stomp switch.

Is there a way that I can simulate a stomp switch using other components?

Additionally, I have questions about some of the information on here. All of the switch items have grounds near then that are not connected to anything. Is this to implicate that when the switch is toggled, it will change its connection to the ground?

Lastly, the ground icons on INPUT and OUTPUT have these flags on them. My general assumption is that its just to imply the jacks and nothing more, but I wasn't sure if this was to mean something different than that.

I have the file that can be loaded to the simulation if anyone wanted to take a look at it as well.

Thank you in advanced.

 

[vigilante398]

Welcome to the forum

I can only speak for myself, but personally I almost never simulate circuits before building them. If I want to experiment with something before committing to building it I'll try it out on the breadboard so I can actually hear it real time, but simulations are only capable of giving certain types of data, and looking at a waveform doesn't always give us great insight into what something is going to sound like.

I will caveat that one thing I do frequently simulate is weird power supply circuits. I use a lot of Analog Devices components for power conversion, and LTSpice has all of the parts I use so it's easy to simulate how things are going to behave at circuit startup, what ripple characteristics will look like under certain loads, etc. For DC supplies you can gain a lot more information from looking at a plot than you can from looking at an audio waveform.

Hope this helps

 

[raddad92]

Welcome to the forum

I can only speak for myself, but personally I almost never simulate circuits before building them. If I want to experiment with something before committing to building it I'll try it out on the breadboard so I can actually hear it real time, but simulations are only capable of giving certain types of data, and looking at a waveform doesn't always give us great insight into what something is going to sound like.

I will caveat that one thing I do frequently simulate is weird power supply circuits. I use a lot of Analog Devices components for power conversion, and LTSpice has all of the parts I use so it's easy to simulate how things are going to behave at circuit startup, what ripple characteristics will look like under certain loads, etc. For DC supplies you can gain a lot more information from looking at a plot than you can from looking at an audio waveform.

Hope this helps

Thank you for your reply. I got LTSpice as an additional tool to try different simulations, but found it somewhat overwhelming as someone that is largely unfamiliar with a lot of what I'm looking at. I was able to get a *mostly* functioning circuit with Falstad with a bit of mickey-mousing, but its still not exact and it seems like a good portion of what isn't responding correctly is because I haven't figured out how to include a stomp switch as a device on the simulation. Even then, its not for determining the sound, its just to determine if I'm going to blow my stuff up or if it will at least function. Really, my first goal here is "make something work at all successfully, even if its not exact".

I have a small breadboard, but not enough space to do what I want to do. I suppose I may just need to get a larger one to try. I otherwise have all of the components I need for most of the materials, barring the specific resistors and capacitors for a few of the connections. For the resistors I figure a small increase of resistance would be generally negligible, but its the capacitors that I'm more worried about. Part of this was to test if what I have would work, but I also wanted to try to simulate it so I could experiment with other configurations quickly by loading the file and making adjustments on the values. Would be a lot quicker than setting up a breadboard over and over.

I'm still hoping that maybe someone might have some idea on how I could artificially simulate the stomp switch, but if not I may just have to wait until I can get a larger breadboard and hope I don't destroy the equipment I have lol.

 

[jwin615]

For all intensive porpoises, the stomp switch matters zero to that circuit(and any circuit where it's just a bypass). No need to simulate it. Omit it, the led and CLR.

 

[raddad92]

For all intensive porpoises, the stomp switch matters zero to that circuit(and any circuit where it's just a bypass). No need to simulate it. Omit it, the led and CLR.

I suppose that's completely logical, and really simplifies everything. I feel silly for not really even considering it. I understand the basis of how the stomp switch works so its not like I need it, I just wasn't sure if it actually had any meaningful impact on the numbers behind it and would substantially adjust the values of the current as it was registered. Thanks, I'll give it a shot!

 

[jwin615]

The led and CLR would add to current draw, minimally.
I'll echo that your better off in another sim program. Need one that you can feed white noise in and get a frequency response out to be meaningful when it comes to mods.

 

[raddad92]

The led and CLR would add to current draw, minimally.
I'll echo that your better off in another sim program. Need one that you can feed white noise in and get a frequency response out to be meaningful when it comes to mods.

Yeah at this point I've opted to pick up a larger breadboard so I can test it, and have used the simulation without the LED and CLR to get a better idea on how it runs. While I haven't had the time to adjust the settings on the simulation to match the equipment I have, I can't imagine the slight adjustment to the increase in resistance or capacity for a few select parts will ruin everything. Its not as if I'm putting stuff that's substantially different. Falstad does allow me to have audio input, and it works to a degree, but it was always about just checking to see if I would blow myself up or not.

I'd like to thank everyone that replied, I was pleasantly surprised to have relatively quick responses!