Epoch Bias

The Catalinbread Epoch Bias captures the preamp section of the Echoplex EP-3 tape delay, which guitarists discovered added warmth and presence even with the delay turned off. The Preamp control sets the input gain, Boost provides clean output level increase, and the Bias knob adjusts the operating point of the circuit for different textures—from clean and open to saggy and compressed.

The Filter control rolls off highs for a darker, more vintage character. Internally the circuit runs at 22V via a charge pump despite accepting standard 9V DC input at 18mA, giving it more headroom than you'd expect from the compact enclosure.

The EP-3 preamp has been a secret weapon on countless recordings—this isolates that specific tonal contribution without needing a full tape echo unit. Stacks well at the front of a signal chain as an always-on tone shaper.