Duncan Amplification DDS-2250V - Channel B preset

Verified · 90/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The DDS-2250V is a one-off all-valve stereo rack head built by Duncan Amplification, not a production model. Two relay-switched 12AX7 channels each have their own gain, bass, treble and level: Channel A adds a Turbo stage, Channel B two footswitchable gain settings. A switching module adds a stereo effects loop and two masters, feeding two identical 50-watt power amps, each a 12AX7 driver and 12AT7 inverter into a fixed-bias pair of 6L6WGBs.

• Wattage: 100W
• Channels: 2
• Preamp tubes: 6× 12AX7, 2× 12AT7
• Power tubes: 4× 6L6WGB

Tags: stereo, 6l6, two-channel, high-wattage.

Schematic-derived preset files for 16 Fractal and Line 6 modelers: Axe-Fx II/XL/XL+, Axe-Fx III, FM3, FM9, and the full Helix family (Floor, LT, Rack, HX Stomp, HX Stomp XL, Native).

Gridleak extracts amp parameters from original circuit schematics using AI vision — component values, gain staging, tone stack topology, tube types — then generates native preset files for every supported modeler. Every extraction is scored 0–100 and the score is published.