The Fernandes Sustainer

It feeds energy into vibrating strings to extend notes and encourage harmonics. Chords can respond, but individual notes may develop unevenly. The effect does not depend on high amplifier volume or an external sustain device.

A driver in the neck pickup position generates a magnetic field that keeps the strings vibrating, working together with the bridge pickup and a small circuit board. It runs on a 9-volt battery, so it feeds energy back into the strings the way a loud amp would, but under your control.

Natural mode maintains the fundamental pitch. Harmonic mode encourages an overtone. Mix combines those responses on versions that support it, including the FSK-401; do not assume every Sustainer has all three settings.

The Elite and JP Elite models, the Pro line, the Classic series, and some Deluxe Tremolo Sustainer versions shipped with it installed. On this site, any model tagged with the Sustainer in its spec has the system built in.

The FSK-401 is the original kit with a single-coil-size driver and a full electronics package, including Mix mode. The FSK-101 is a simpler, more affordable kit with a humbucker-size driver, meant for guitars set up for a neck humbucker.

First check the kit’s driver dimensions, control layout, and wiring diagram against your guitar. Installation may require additional space for the circuit board or battery. A matching pickup outline by itself does not confirm electrical compatibility.

The main things that matter are the neck pickup size (single-coil vs humbucker), room for the electronics and a 9-volt battery, and a bridge pickup to pair with. Passive-friendly wiring helps. If you are unsure, a luthier can confirm before you buy a kit.

Yes. It runs on a standard 9-volt battery. As with active pickups, unplug the guitar when you are not playing to preserve battery life, since leaving a cable in the jack keeps the circuit powered.

An E-Bow is a handheld device you hold over one string, so it ties up your picking hand and works a note at a time. The Sustainer is built into the guitar and driven from the neck, so it works across the strings while you keep both hands free to play normally.

Both are built-in sustain systems with similar goals and modes. Players tend to choose based on feel, availability, and how cleanly the system integrates. Many Fernandes owners prefer the original Fernandes system for how it was integrated into their guitar.

An external amplifier is not needed for the magnetic driver to move the strings. That does not mean the output jack can be left empty: on typical wiring, inserting a cable completes the battery circuit. Test a used system with a fresh battery and the output cable connected.

Fernandes no longer makes new Sustainer kits, but used FSK-401 and FSK-101 kits, spare drivers, and circuit boards still change hands among enthusiasts. Check the used market and community forums, and confirm the kit is complete before buying.

Long, vocal-like lead lines, swells, drones, ambient textures, and controlled feedback that would otherwise need a loud amp or a handheld device. It suits everything from atmospheric parts to screaming feedback, all under your control.

The driver sustains motion magnetically rather than rubbing against a string. Proper installation and adjustment still matter. Inspect battery corrosion, damaged wiring, or a driver positioned too close to the strings before using an unfamiliar instrument.

On the used market. eBay is the most reliable place for both Sustainer-equipped guitars and the kits, with sellers who ship worldwide. For a guitar, look for the Elite, Pro, or Classic models; for a retrofit, look for a complete FSK-401 or FSK-101.