Rock and Blue SPRO Guitar Wiring Harnesses

All SPRO products come with a 1-year limited warranty, pending receipt/proof of purchase.

Electromagnetic Interference (EMI) refers to electromagnetic energy that disrupts the functioning of electronic devices. EMI can originate from natural sources, such as electrical storms and solar radiation, or human-made sources, including power lines, cell phones, motors, and LED screens. Additionally, inherent EMI can arise from a device’s own internal electrical systems interacting with other components.

Electromagnetic Compatibility (EMC) measures a device's ability to operate as intended in its environment while minimizing the effects of EMI on itself and other devices. EMC involves two key aspects: immunity (how well a device resists EMI) and emissions (how much EMI the device generates). Both are critical considerations in guitar wiring systems.

High levels of EMI can degrade guitar performance by introducing noise or hum into the signal chain. This interference is particularly problematic in environments with multiple electronic devices, such as rehearsal studios or live venues. Sources like WiFi signals, fluorescent lighting, and nearby transformers can exacerbate these issues.

SPRO wiring boards are engineered to address EMI challenges effectively. By incorporating advanced shielding techniques and carefully designed circuit layouts, SPRO boards minimize susceptibility to EMI and ensure superior performance. This includes reducing radiated and conducted interference from external sources while maintaining compatibility with other electronic systems.

SPRO boards are designed to deliver clean, noise-free operation even in challenging electromagnetic environments. Whether you're dealing with human-made EMI, natural interference, or inherent device noise, SPRO boards provide exceptional immunity to these disturbances. The result is a highly reliable product that ensures optimal guitar tone and functionality in any setting.

The only wiring required for SPRO boards is to connect the pickups to the terminals on the board. Please refer to our SPRO and Free-Way wiring PDF.

At a minimum, you will need a soldering iron and solder, a small Philips head screwdriver, and wire cutters/snips.

No, however some soldering experience is recommended. If you are not confident about your soldering skills, we recommend reviewing a few YouTube videos on the subject prior to attempting to solder.

All our wiring kits use Bourns button size potentiometers (250k and 500k, with blender and tone pots no-load), metal film Panasonic pro capacitors (.022uF and .047uF, or the SUM of them), and CUI surface-mounted microswitches.

No-load tone pots look and function exactly like regular tone pots. When turned between 1–9, they work like a regular tone pot. The difference is when the pot is rotated between 9 and 10, it acts as a true bypass system and essentially removes the tone pot and capacitor from the wiring circuit. This means if your tone pot is at position 10, you will be hearing the direct, unfiltered sound of your pickup. This gives you a little more diversity with your guitar. Turning the tone pot to 10 can slightly increase the output and brightness of the pickup attached to it.

Typically, both Tone and Volume controls connect to Ground. These connections will cause some of your high-end frequencies to leak to Ground, which will result in a warmer tone from the guitar.

A guitar’s manufacturer chooses the values of Volume and Tone controls based on the type of pickups being used. For single-coils that are often very bright and sometimes harsh or brittle sounding, manufacturers use 250k pots, which allow a lot of high-end to escape to Ground, warming up the tone and making single-coil pickups more useful and musical.

Humbucker pickups are naturally warmer sounding, so using 250k pots could result in a very dark and muddy tone. For that reason, humbuckers use 500k potentiometers, which allow less high-end to escape and sound brighter. No matter what value you use, standard pots are always slightly ON and therefore will continuously leak some high-end frequencies to Ground.

No-load pots can be 250k or 500k, and they will operate as usual from one to nine but shut off at ten. When they shut off, the connection to Ground is severed, and no high-end frequencies can escape to Ground. This configuration leads to the brightest possible guitar tone.