Standel SI15B / I12B / I15B / SA15B / A20B / A12B / A15B / A10B - Normal preset

Verified · 84/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

This 1968 Standel drawing covers a family of all-transistor bass amps (SI15B, I12B, I15B, SA15B, A20B, A12B, A15B, A10B). Normal and Bass inputs each run through their own potted preamp module with their own Volume, Treble and Bass controls (plus a Contour control on the SI15B and I12B). The two mix into a third module and an S2771 driver, which feeds S2773 output transistors in quasi-push-pull through a driver transformer, from ±32 V rails into a 4-ohm speaker. The A15B and A10B use one output pair instead of two.

• Made in: USA
• Channels: 2

Tags: american, vintage, bass, solid-state, two-channel.

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.