Technical library
Curves, circuits and every number
Explore the signal path, current fitted values and documented bench results. Circuit models illustrate behavior where a measured result has not been supplied.
Explore the earlier filter model
This explorer retains the earlier component-based filter model and illustrative notch fit. It excludes the new U3A presence shelf and is not the current production response. The production Aurora Curtain closed corner is about 3 kHz; use the updated drive sweep and written comparison for the current voicing.
Earlier component model, excluding the production presence shelf; notch depth is an illustrative bench fit.
Where the instruments live
Instrument fundamentals shown for context. The combined pedal response depends on filter settings, coupling corners and the selected clipping and dynamics stages.
What has been measured
The November 1 production brief supplies the current drive sweep, re-voicing anchors and compressor threshold, slope and clamp. The earlier Revision C / Rev 2 Word records remain dated sources; the updated production references below take precedence.
On a narrow screen, scroll the table sideways to read every column.
| Subject | Available evidence | Scope |
|---|---|---|
| Compressor | November production brief: TP1 threshold about 0.4 V peak, reduction about 15 dB/V above it, maximum about 21 dB. | JP1 A, feed-forward Audio_In; JP2 B, clean Wall of Ice key via J23 → J10. Current resistance-based preset replaces earlier feedback percentages. |
| Drive | November production: three-leg voicing, maximum effective feedback 23 kΩ with R54 220 kΩ; R53 470 Ω. Ring knee around 9 V, ceiling around 12 V. Ladder shoulders ±3.65 V, flat clamps ±4.55 V. U3A adds about +4 dB presence above 3 kHz. | Supplied AD3 response tables: 20 mV drive, Dist 12.2 kΩ, filters open, 10× output probe with correction included. Production values supersede earlier exports. |
| Twin Assassins | Supplied bench centres near 325 Hz and 630 Hz, with cuts around −12 dB and −5 dB at the notched blend end. | The explorer fits those centres and depths illustratively; widths and intermediate blend positions are not new measurements. |
| Filter and supply curves | Component-based models and analytical illustrations. | They describe their stated circuit or node. They are not measurements of complete-pedal bandwidth, output noise, supply ripple under load or J2 impedance. |
| Input current | 148 mA at 9 V in the documented October bench setup. | One setup, not a guaranteed maximum for every setting or unit. Use a supply with startup margin. |
No measured input-referred noise, whole-pedal output-noise or clean-path THD+N specification is claimed from these sources. Device specifications and model predictions are identified separately from bench results.
November production update
Read the production signal path and component values, including the three drive voicing legs, presence shelf and feed-forward compressor setup.
Circuit references
Each section of the pedal, with the reasoning behind every value.
Drive architecture and circuit update
Cascaded clipping and independent dynamics
LED feedback, silicon/zener ladder, two-transistor fuzz, switchable VCA processing and the latest supplied export comparison.
Wall of Ice
Input stage and high-pass filter
The high-impedance input network, JFET first stage and fourth-order Butterworth high-pass that shapes what reaches the drive.
Twin Assassins
Dual notch network
The bench-tuned twin-T pair, measured near 325 Hz and 630 Hz, its fitted parts and the Notch Blend control.
The Drive of Malice
Three clipping tiers on ±15 V
November production values and supplied bench data are now reflected in the drive and compressor references, including the three-leg voicing, symmetric production ladder and resistance-based dynamics preset.
Aurora Curtain
Two staggered low-pass sections
Why the last two poles are held back, with the response at every point of the knob.
Production board map and setupCuk-Linear Dual Reactor
Dual-rail power supply
How one LT3471 makes clean ±15 V rails from a pedal supply: the converters, the filtering and the capacitance multipliers.
| Sources | Guitar, bass, synthesizer, keyboards, drum machines, line-level gear. Unbalanced ¼″ in and out. |
|---|---|
| Frequency response | Reported low-frequency response with filters open: flat to ±0.1 dB from 20 Hz upward in the low-frequency band. Every inter-stage coupling corner is below 2 Hz. Drive voicing, the presence shelf, deliberate filters and CRz still shape the full response. |
| Settling | CRz overload recovery with fuzz engaged: about 50 ms, fuzz stage only. No single whole-pedal settling time is specified. |
| Input | High-impedance JFET input. The available high-pass netlist has two 4.7 MΩ shunt resistors, giving approximately 2.35 MΩ combined resistive loading where coupling passes the signal. RF capacitance makes impedance frequency-dependent; no measured input-impedance sweep or whole-pedal noise figure is supplied. |
| Wall of Ice | 4th-order Butterworth high-pass, 24 dB/octave, ≈ 12 Hz to 490 Hz |
| Twin Assassins | Retuned dual notch: about −12 dB at 325 Hz and −5 dB at 630 Hz at the fully notched blend end; about −6 / −3 dB near two-thirds travel |
| Drive | November production: three-leg voicing, maximum effective feedback 23 kΩ with R54 220 kΩ; R53 470 Ω. Ring knee around 9 V, ceiling around 12 V. Ladder shoulders ±3.65 V, flat clamps ±4.55 V. U3A adds about +4 dB presence above 3 kHz. |
| Aurora Curtain | Four-pole low-pass on a 200 kΩ control, closed corner about 3 kHz, matched to the U3A presence shelf. Broadly flat below the roll-off when closed; about +4 dB presence when open. |
| Stiward Thære SæSteward of the Seas | SSI2162 compressor and gate, thirteen trimmers. Shipped JP1 A, feed-forward Audio_In, PEAK unbridged; JP2 B, clean key from Wall of Ice via J23 → J10. TP1 threshold about 0.4 V peak; maximum reduction about 21 dB. R31/R48 2.2 kΩ, R29/R95 100 kΩ, R33 1 MΩ, R39 100 kΩ, C56 220 nF. |
| Controls | Five knobs (Wall of Ice, Twin Assassins Notch Blend, Dist, Aurora Curtain, Volume), three switches (Comp, Clean, CRz) and the footswitch. Clockwise means more. Three fuzz trimmers and the op amp socket behind the portal plate. |
| Power | Regulated 9 V DC pedal supply, center-negative, 2.1 mm. Measured 148 mA in the October 2026 bench setup; use an output rated 300 mA or more (500 mA recommended). A regulated 12 V supply also works. Reverse-polarity protected, with limited over-voltage protection and a surge suppressor on the jack. Designed for 9 V or regulated 12 V; don’t use an 18 V supply. Not for unregulated adapters; see power and protection. |
| Internal rails | ±15 V bipolar with a real ground from the Ćuk-Linear Dual Reactor; locking rail-lead connectors. |
| Enclosure | 125B-size, tentacle relief, iridescent knobs, illuminated porthole window |
| Power board | The Ćuk-Linear Dual Reactor. One LT3471 controller runs a boost converter for the positive rail and a Ćuk inverter for the negative rail. Each rail then passes through an R–L–C filter (1 Ω, 10 µH, 2000 µF), a single-transistor capacitance multiplier and a ferrite-bead stage before the output connector, arriving at about ±15 V. The six-layer board is 60 × 23 mm and stands on edge at the end of the stack. |
|---|---|
| Rails | Approximately ±15 V at the Reactor connector. Per-board isolation resistors and local decoupling affect what each amplifier sees. The capacitor-bank model is before the multiplier; no measured output-impedance figure at J2 is specified. |
| Ground | The audio is referenced to a copper ground plane on the bipolar supply. This avoids a mid-supply bias reference; it does not eliminate every shared-impedance or coupling mechanism. |
| Noise | The LT3471 switches at 1.2 MHz. The filter and multiplier models estimate attenuation at their stated nodes. These calculations are not a measured supply-ripple, output-noise or THD+N specification for the assembled pedal. |
| Surge | A bidirectional TVS (SMAJ18CA) across the DC jack on the Drive of Malice board clamps spikes before anything else sees them. |
| Reverse polarity | Q6, a P-channel MOSFET at the DC input, provides reverse-polarity blocking. In the normal direction it has finite on-resistance rather than a series diode drop. Use the specified supply polarity. |
| Over-voltage protection | A second P-channel MOSFET (Q7) after it. A 13 V zener and a PNP switch are there to turn it off when the input passes about 14 V, disconnecting the power board and everything after it. It is limited protection and isn’t guaranteed: the pedal is designed for 9 V or a regulated 12 V supply, so don’t plug in an 18 V supply. |
| Indicator LED | The LED supply has its own series Schottky diode (D11), rated for at least 20 V reversed. |
| Power board clamp | D18 provides an over-voltage clamp at the converter input, with R2 in series. Excess input voltage can damage these and other components; check the protection circuit, both rails and board currents after an event. |
| Rail faults | D3 and D4 clamp reverse excursions at the power-board output if one rail collapses. Protection limits specific fault mechanisms; inspect the hardware before powering it again after a fault. |
| Power-up | R2 limits inrush into the reservoir capacitors, and a soft-start (R37, R38, C14, C15) with the capacitance-multiplier filters brings the rails up over a quarter to half a second. A 500 mA output gives extra start-up margin; how a supply handles the plug-in spike depends on its own current limiting. |
| Each audio board | Local supply resistors and decoupling provide filtering and isolation. Check their voltage drops to localize abnormal current. They do not guarantee that all fault damage is confined to the entry resistor. |
Service: dead after an unregulated adapter
After an incorrect supply, check the protection circuit and rails before replacing parts. R2 and D18 may be damaged by an over-voltage event; Q1 may be damaged by a rail short. Identify and clear the fault, replace damaged parts as required, then verify both rails and audio-board currents. The rest of the circuit must be checked rather than assumed undamaged.