Pedal Schematic — Blackstar Ht Dual

The 12AX7 requires a specific filament voltage (usually 6.3V or 12.6V). If your pedal isn't lighting up or passing signal, this is the first place to check for a blown component. ⚠️ A Critical Warning The HT-Dual is not a beginner project for DIY repair. Lethal Voltages: The internal 300V rail can be fatal.

The pedal takes 16V AC and boosts it internally to roughly 300V DC. This "B+" voltage is what allows the 12AX7 (ECC83) tube to operate in its linear region, providing real headroom. Blackstar Ht Dual Pedal Schematic

Both halves of the tube are utilized. One half typically handles the initial gain stage, while the second provides additional clipping and drive. The 12AX7 requires a specific filament voltage (usually 6

A dedicated filtering circuit at the end of the chain that rolls off high frequencies to mimic a 4x12 cabinet. Lethal Voltages: The internal 300V rail can be fatal

Understanding the schematic is key to maintaining, modding, or cloning this beast of a pedal. ⚡ The Core Architecture

A complex arrangement of FET switches and logic gates that toggle between the "Clean/Crunch" channel and the high-gain "Lead" channel.

A high-impedance stage that preserves your guitar's high-end before the gain stages.