Rockin’ Out In LTSpice: Simulating Classic Guitar Pedals

Musicians have a fantastic language to describe signals. A sound can be fat, dark, crunchy, punchy — the list goes on. These aren’t very technical terms, but they get the job done. After all, it’s much easier to ask to guitarist for a crisper sound than to ask them to sharpen the edges of the waveform, while amplifying the high-frequency components and attenuating the low-frequency components. Of course, it’s fun to look at signals this way as well, especially when you can correlate shifts in sound quality to changes in the waveform and, ideally, the circuit that produces it.

To undergo such an investigation, [Nash Reilly] has been simulating guitar effects pedals in LTSpice. Able to find most of the schematics he needs online, [Nash] breaks down the function of each part of the circuit and builds a simulation of the entire system. His write-up clearly explains, and often demonstrates, what’s going on inside the box. On the surface, it’s an interesting tour of the inner workings of your favorite effects pedals. Beyond that, it’s an excellent survey of analog design that is well-worth the read for anybody interested in audio, electronics, or audio electronics.

For those interested in taking the physical route rather than the simulated one, we’ve taken a look at pedal design before. Anybody who wants to try their hand at creating simulations can grab a copy of LTSpice, or check out a package called LiveSpice, which lets you simulate circuits in realtime and use them to process live audio — pretty useful for prototyping guitar effects.

Power Your Guitar Pedals With Drill Batteries

Guitar pedals are a great way to experiment with the sound of your instrument. However, they require electricity, and when you’re using more than a couple, it can get messy. Some will run on batteries, while others are thirstier for more current and will only work with a plugback. There are a great many solutions out there, but most people with more than a few pedals to power will end up going to some kind of mains powered solution. [Don] is here to show us that it’s not the only way.

Mains power is great for some things, but where pedals are concerned, it’s not always perfect. There are issues with noise, both from cheap power supplies and poorly designed pedals, and it means you’re always hunting for a power socket, which is limiting for buskers.

[Don] realised that the common drill battery is a compact source of clean, DC power, and decided to use that to power his rig. By slapping together a drill battery with a pre-assembled buck converter and a 3D printed adapter, he was able to build a portable power supply for his pedals. Thanks to the fact that the vast majority of pedals use 9V DC with the same input jack design, it’s a cinch to wire up. With an appropriately sized buck converter, a drill battery could supply even a hefty pedalboard for a significant period of time.

Overall, it’s a great hack that solves a problem faced by many performing musicians. We’ve seen our fair share of guitar pedals around Hackaday – perhaps you’d like to see how one makes it from concept to production?

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