125B · 3 knobs
TesseractBoost / Preamp
Based on the TC Electronic Integrated Pre
- Category
- Boost· Boost / Preamp
- Controls
- Bass · Treble · Level
- Difficulty
- Intermediate
- Price
- $12.50in stock
From the vendor
A pedal adaptation of the legendary booster and tone shaper famously used by Meshuggah.
The Tesseract Boost/Preamp is an adaptation of the TC Electronic Integrated Preamp, a boost & EQ from the late 1970s. The Integrated Pre is so named because it’s designed to connect directly to your guitar, which is why the original unit did not have a bypass switch.
The Integrated Preamp gained fame as the secret behind Meshuggah’s guitar tone in the 1990s. The boost was perfect for pushing the front of their Mesa/Boogie Dual Rectifiers and the EQ can cut bass for a tighter driven tone.
The original unit could run on as much as 32V using an external supply, or it could operate at the standard 9V using a battery. Since 32V supplies are hard to come by, the Tesseract Boost/Preamp includes an on-board charge pump that quadruples the input voltage (minus a few diode drops), allowing a 32V operation from a standard 9V supply.
The only other modification is the removal of a pop-suppression circuit at the input. This is designed to prevent the loud pop when the input jack is first plugged in. It’s useful in the original unit that connected straight to the guitar since the preamp would reasonably be plugged & unplugged in a live setting. However, in pedal format, the suppression circuit has no function other than to increase the current consumption as it is always bleeding some of the supply voltage to ground. There is no impact to the tone or functionality if it’s omitted.
Note: This project uses a type of capacitor that has been temporarily discontinued by WIMA. Please see our news article about the issue and the substitution spreadsheet for project-specific recommendations. We are stocking a limited supply in the mean time. The build document has not yet been updated to reflect this.
Schematic
The schematic is in the vendor's build document, page 6. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 54 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 13 | ||||
| R1 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R2 | 6M8 | 6.8M | Metal film resistor, 1/4W | |
| R3 | 100k | 100k | Metal film resistor, 1/4W | |
| R4 | 220k | 220k | Metal film resistor, 1/4W | |
| R5 | 470R | 470 | Metal film resistor, 1/4W | |
| R6 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R7 | 8k2 | 8.2k | Metal film resistor, 1/4W | |
| R8 | 220R | 220 | Metal film resistor, 1/4W | |
| R9 | 10k | 10k | Metal film resistor, 1/4W | |
| R10 | 100k | 100k | Metal film resistor, 1/4W | |
| R11 | 1M | 1M | Metal film resistor, 1/4W | R11 is shown as 820k in one of the two known factory schematics. |
| RPD | 2M2 | 2.2M | Metal film resistor, 1/4W | Input pulldown resistor. |
| LEDR | 4k7 | 4.7k | Metal film resistor, 1/4W | LED current-limiting resistor. Adjust value to change LED brightness. |
| Capacitors 19 | ||||
| C1 | 47n | 47n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 100pF | 100p | MLCC capacitor, NP0/C0G | |
| C3 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C4 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C5 | 4n7 | 4.7n | Film capacitor, 7.2 x 2.5mm | |
| C6 | 47n | 47n | Film capacitor, 7.2 x 2.5mm | |
| C7 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C8 | 220n | 220n | Film capacitor, 7.2 x 2.5mm | |
| C9 | 100uF | 100u | Electrolytic capacitor, 6.3mm | |
| C10 | 470n | 470n | MLCC capacitor, X7R | |
| C11 | 10uF | 10u | Electrolytic capacitor, 5mm | Must be rated for at least 50V. |
| C12 | 10uF | 10u | Electrolytic capacitor, 5mm | Must be rated for at least 50V. |
| C13 | 10uF | 10u | Electrolytic capacitor, 5mm | Must be rated for at least 50V. |
| C14 | 10uF | 10u | Electrolytic capacitor, 5mm | Must be rated for at least 50V. |
| C15 | 10uF | 10u | Electrolytic capacitor, 5mm | Must be rated for at least 50V. |
| C16 | 47uF | 47u | Electrolytic capacitor, 6.3mm | Must be rated for at least 50V. |
| C17 | 470n | 470n | MLCC capacitor, X7R | |
| C18 | 10uF | 10u | Electrolytic capacitor, 5mm | Must be rated for at least 50V. |
| C19 | 100n | 100n | MLCC capacitor, X7R | |
| Diodes 8 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | 1N4742A | 1N4742A | Zener diode, 12V, DO-41 | |
| D3 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D4 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D5 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D6 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D7 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D8 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| Transistors 1 | ||||
| Q1 | 2N5088 | 2N5088 | BJT transistor, NPN, TO-92 | Original uses BC548C, which will need to be rotated 180 degrees if used since the pinout is mirrored. |
| ICs 2 | ||||
| IC1 | LM741 | LM741 | Operational amplifier, DIP8 | Factory schematic also specifies TL071 and LF356, but all photos of real units show LM741. |
| IC2 | LT1054CP | LT1054CP | Charge pump, DIP8 | |
| Potentiometers 2 | ||||
| BASS | 50kC | C50k | 16mm right-angle PCB mount pot | |
| LEVEL | 50kA | A50k | 16mm right-angle PCB mount pot | |
| Switches 1 | ||||
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| LEDs 1 | ||||
| LED | 5mm | 5MM | LED, 5mm, red diffused | |
| Jacks & sockets 5 | ||||
| IC1-S | DIP-8 socket | DIP-8 SOCKET | IC socket, DIP-8 | |
| IC2-S | DIP-8 socket | DIP-8 SOCKET | IC socket, DIP-8 | |
| IN | 1/4" stereo | 1/4" STEREO | 1/4" phone jack, closed frame | Switchcraft 112BX or equivalent. |
| OUT | 1/4" mono | 1/4" MONO | 1/4" phone jack, closed frame | Switchcraft 111X or equivalent. |
| DC | 2.1mm | 2.1MM | DC jack, 2.1mm panel mount | Mouser 163-4302-E or equivalent. |
| Hardware 2 | ||||
| BATT | Battery snap | BATTERY SNAP | 9V battery snap | Optional. Use the soft plastic type—the hard-shell type will not fit. |
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |