Carlsbro CS40 Top preset

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

The CS40 Top is a 40-watt Carlsbro valve head, built on the same single-channel circuit as the 50 Top. Two inputs feed the first half of an ECC83, then a treble, bass and middle stack and a volume control before the second half. A second ECC83 long-tail phase inverter, with negative feedback from the speaker output, drives a pair of fixed-bias EL34s from a silicon bridge rectifier with standby, into 3.75, 7.5 and 15 ohm taps.

• Made in: UK
• Wattage: 40W
• Channels: 1
• Preamp tubes: 2× ECC83
• Power tubes: 2× EL34

Tags: british, vintage, el34, mid-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.