Keeley Electronics Mk3 Muse Driver – Full Range Overdrive

The Keeley Muse Driver — currently sold as the Mk3 Driver following a recent name change — is a full-range overdrive built in collaboration with Andy Timmons.

It’s the most evolved version of a circuit lineage that started with Keeley’s original Phat Mod to the Boss BD-2, refined through the Luna Overdrive, the Katana Blues Drive, and the Super Phat Mod. And now the Mk3.

Andy Timmons has used Keeley-modified Blues Drivers as a core part of his tone for years. The Muse Driver gives him four different voices of that circuit in one pedal.

Andy says: “The AT/AT setting is exactly my Super AT Mod tone — just the right amount of breakup available at your dynamic command. Every note and nuance is clear as a bell.

The RK modded BD-2 circuit is the circuit I fell in love with years ago and it still inspires me. The germanium diodes are the hidden gem — a new kind of clipping that works insanely well on its own or as a boost for lead tone.”

The Four Voices

The AT/RK Tone switch and AT/RK Drive switch together give four combinations — four fundamentally different overdrive voices from the same pedal.

• AT Tone: Andy’s preferred low-end voicing. Each note in a chord stays clear and articulate.
• RK Tone: The legendary Phat Boost low-end frequency response. More body in the low-mids — aimed particularly at single coil pickups.
• AT Drive: Asymmetrical LED diode clipping for a brighter, more articulate attack. Andy’s Super AT Mod sound.
• RK Drive: Two germanium diodes in the clipping circuit. Softer, more vintage in character — more compressed at higher Drive settings.

The circuit combines JFET saturation, diode clipping, and op-amp clipping — three different types of gain working together to create the harmonic richness that makes all four voices sound musical rather than harsh.

Running at 18V

The Muse / Mk3 Driver runs on 9V to 18V DC. Running at 18V increases headroom significantly for more dynamic range and a more open, responsive feel. The CIOKS DC7 v2 is the ideal supply for this — each outlet supports selectable voltages of 9V, 12V, 15V, or 18V via DIP switches, so you can run the Muse Driver at 18V from the same supply as the rest of your board.

The Bypass

The Muse Driver is one of the few pedals that lets you switch between true bypass and buffered bypass on the fly. Hold the footswitch for two seconds to toggle between them — no need to open the pedal or change any internal setting.

Controls

• Level: Controls the output level.
• Tone: Controls the high-frequency character.
• Drive: Controls the amount of gain from the circuit.
• AT/RK Tone switch: Toggles between Andy’s preferred articulate low-end response (AT) and Robert Keeley’s Phat Boost low-end voicing (RK).
• AT/RK Drive switch: Toggles between asymmetrical LED diode clipping for Andy’s Super AT Mod character (AT) and dual germanium diode clipping for a softer, more compressed vintage character (RK).

Key Features

• Full-range overdrive — clean boost to square-wave fuzz-like saturation
• Built with Andy Timmons — AT/RK naming reflects Andy’s and Robert Keeley’s preferred voicings
• Four distinct drive voices from two toggle switch combinations
• JFET saturation, diode clipping, and op-amp clipping combined
• Switchable true bypass or buffered bypass on the fly — hold footswitch for 2 seconds
• 9V to 18V DC operation — 18V increases headroom and dynamic range significantly
• Current consumption: 40mA
• Made in the USA
• Also sold as: Keeley Mk3 Driver (name changed for legal reasons — same circuit)

Watch the Mk3 / Muse Driver In Action

FAQs