Keeley Unleashes 168V High-Voltage Tube Drives

Keeley Electronics Unveils High-Voltage Tube Drive Pedals: The Twin Triode and Limited Edition 12AT7WC

Keeley Electronics has set a new standard for amp-in-a-box tone with the release of two formidable dual overdrive pedals: the standard-production Twin Triode 12AX7 and the highly exclusive Limited Edition 12AT7WC.

By pairing genuine high-voltage vacuum tube preamps with their legendary Phat Mod circuit, Keeley has delivered a pair of gig-ready stompboxes designed to be the tonal foundation of any modern pedalboard.

Genuine 168V Tube Operation: No "Starved Plates"

Many so-called "tube pedals" on the market rely on starved-plate designs, supplying just enough voltage to light the glass while relying on solid-state clipping for the actual dirt. Keeley has taken the uncompromising route. Both pedals run their central tubes at an astonishing 168 Volts, allowing the valve to operate exactly as it would inside a pushed amplifier.

This high-voltage environment yields massive headroom, a highly musical and elastic compression when you dig in, and the ability to clean up beautifully when you roll your guitar’s volume back. The result is a pedal that doesn't just sound like an amp—it feels like one.

The Legendary Phat Mod Heritage

Alongside the tube channel sits Keeley’s acclaimed Phat Mod drive. Originally famous for transforming the stock Boss BD-2 Blues Driver into a boutique, touch-sensitive powerhouse, this circuit provides everything from low-gain, edge-of-breakup grit to thick, sustaining lead tones.

Each channel—Tube and Drive—features fully independent Level, Drive, and Tone controls, allowing you to dial in two completely distinct voices.

Switchable Routing and Pro-Level Control

Keeley designed the Tube Drive series with maximum stage flexibility in mind. A long press on either footswitch unlocks two powerful secondary functions:

• Effect Order: Flip the signal path on the fly. Run the Tube channel into the Phat Mod for an aggressive, cutting modern rock tone, or push the Phat Mod into the Tube for smooth, rounded, vintage-style saturation.
• Bypass Modes: Toggle seamlessly between pure true bypass or Keeley’s silent buffered switching—perfect for preserving signal integrity across long cable runs.

For advanced rigs, a dedicated TRS remote input allows external channel switching via a loop switcher or remote footswitch.

Which Tube Drive is Right for You?

While both pedals share the same rugged, hand-built Oklahoma City construction and 9V DC (485mA) power requirement, the valve at the center of the circuit dramatically changes the pedal's character.

The Limited Edition 12AT7WC is a collector’s dream. Built around a military-grade 1987 Philips JAN tube chosen for its tight tolerances, it excels at transparent, dynamic tone-shaping. The Twin Triode 12AX7, meanwhile, delivers the classic, harmonically rich saturation that 12AX7 tubes are world-renowned for.

Tube-drive pedals can be a lot of fun; I have owned many over the years, including some that are now quite sought-after. Changing tubes can make a difference, as long as the circuit is running at a higher voltage and some 'tube'-driven pedal designs aren't great designs.

However, they don't always play nicely with every guitar amp, so hopefully this new Keeley version will be flexible and usable. It certainly looks very well made, and it sounds like the circuit design really does use those tubes, unlike many poor circuit designs which really don't do the tubes any justice.

It will be interesting to see what guitarists think of this new pedal over the coming months.

Keeley Electronics