The Keeley Tube Drive is one of Robert Keeley’s most ambitious projects. It pairs the legendary Super Phat Mod overdrive circuit with a genuine high-voltage 12AX7 tube preamp running at over 100 volts — real tube warmth, not a digital emulation. Each side runs independently or combined in either order, so you get everything from a clean boost to thick, saturated drive.
The Super Phat Mod side brings that transparent, dynamic JFET overdrive Keeley’s known for, full of harmonic content. The tube stage adds touch-sensitive breakup on a clean amp, or pushes an already-driven amp harder. Run them together and you get an infinite palette of saturation, from subtle grit to scorching leads. Sweetwater’s tone purists love it because you can never have too much tube warmth in your chain.
It’s also built for the modern pedalboard. A remote TRS jack lets you switch each side externally (Tip for Drive, Ring for Tube). It takes 9–18V power so you can dial in headroom. Every 12AX7 is hand-selected and broken in, protected by a custom Keeley shroud with a vented rear panel for airflow. You get true bypass or silent buffered switching, plus a tube-removal tool, shield, and grommet in the box.
How it differs from the 1950 Sylvania 12AT7WA version? – you may wonder. That one is an RKFX.com exclusive that swaps the modern 12AX7 for a vintage 1950s Sylvania 12AT7WA — a tube audiophiles prize for its lush, deep character and military-grade ruggedness. The 12AT7 has lower gain than a 12AX7, so the Sylvania version leans smoother, richer, and slightly less aggressive, with a tweed-style tone stack in the tube stage for dynamic, touch-sensitive breakup. The standard Tube Drive is brighter and more versatile for high-gain; the Sylvania edition is about vintage, NOS tube mojo. Same pedal, different soul.
