Iron Horse

The Iron Horse is Walrus Audio's take on the legendary ProCo RAT circuit, built around the original LM308 chip that gave the vintage RAT its distinctive character. This isn't a clone—it's an evolution that expands the RAT's capabilities.

Level, distortion, and tone controls follow the classic RAT layout. The tone knob operates as a low-pass filter, rolling off highs as you turn it up. This makes it easy to dial in everything from gritty overdrive to thick distortion.

The LM308 chip's slower slew rate contributes to that distinctive fuzzy edge that sets the RAT apart from other distortion circuits. The Iron Horse captures this character while adding build quality and reliability improvements over vintage units.