125B · 5 knobs
From the vendor
The original transparent overdrive, designed to bring out the best in the guitar and amplifier. Includes a 2-band tonestack for bass and treble control.
The Termina Transparent Drive is based on the Timmy overdrive pedal from Paul Cochrane, with some modifications adapted from the Vemuram Jan Ray.
The Timmy was originally released in 2004 and is generally credited for kicking off the “transparent overdrive” genre of pedals. It does have a two-band tone control, but generally speaking it’s not designed to have much character of its own, instead bringing out the best qualities of the guitar and amplifier. While it has some similarities to a stripped-down Tube Screamer, there is no trace of the 720Hz mid-hump the Tube Screamer is known for.
The Termina is more specifically based on the Timmy V2 with the clipping diode switch, which is the same version that was licensed to MXR for their Custom Shop mini version. The Timmy V3 “15th Anniversary” edition was released in 2019, moving the diode selector inside the pedal and repurposing the toggle switch as a gain boost.
The Timmy has undergone several circuit changes throughout its run, so there is no single definitive schematic. This excellent research article from ManticoreFX tracks all the known differences, with several collected posts from Paul explaining the changes. The Termina project incorporates all of the revisions prior to the V3 overhaul, while reversing the travel of the bass and treble knobs so they increase the frequencies as they’re turned up instead of cutting as on the V2.
Please see page 10 of the build document for revised licensing terms which are different from our normal projects. The original Timmy pedal remains one of the best deals in the industry and we want to encourage as many people as possible to buy the original if they are able.
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 45 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 13 | ||||
| R1 | 510k | 510k | Metal film resistor, 1/4W | Jan Ray uses 1M. |
| R2 | 3k3 | 3.3k | Metal film resistor, 1/4W | Some Jan Ray units use 33k. |
| R3 | 9k1 | 9.1k | Metal film resistor, 1/4W | Use 3k3 if omitting the bass trimmer mod. |
| R4 | 680R | 680 | Metal film resistor, 1/4W | Part of the bass trimmer mod. See build notes. |
| R5 | 1k | 1k | Metal film resistor, 1/4W | Jan Ray uses 1k2. |
| R6 | 10k | 10k | Metal film resistor, 1/4W | Jan Ray uses 3k3. |
| R7 | 10k | 10k | Metal film resistor, 1/4W | Jan Ray uses 3k3. |
| R8 | 18k | 18k | Metal film resistor, 1/4W | Omit (leave empty) for Jan Ray. |
| R9 | 8k2 | 8.2k | Metal film resistor, 1/4W | Jan Ray uses 9k1. |
| R10 | 10k | 10k | Metal film resistor, 1/4W | Jan Ray uses 7k5. |
| R11 | 100R | 100 | Metal film resistor, 1/4W | |
| 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 11 | ||||
| C1 | 39n | 39n | Film capacitor, 7.2 x 2.5mm | Jan Ray uses 47n. |
| C2 | 47pF | 47p | MLCC capacitor, NP0/C0G | Jan Ray uses 22pF. |
| C3 | 100pF | 100p | MLCC capacitor, NP0/C0G | Jan Ray uses 47pF. |
| C4 | 39n | 39n | Film capacitor, 7.2 x 2.5mm | Some Jan Ray units use 33n. |
| C5 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C6 | 10n | 10n | Film capacitor, 7.2 x 2.5mm | Jan Ray uses 47n. |
| C7 | 2n2 | 2.2n | Film capacitor, 7.2 x 2.5mm | Jan Ray uses 150pF MLCC. |
| C8 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C9 | 47uF | 47u | Electrolytic capacitor, 5mm | Reference voltage filter capacitor. |
| C10 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C11 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| Diodes 6 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D3 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D4 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D5 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D6 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| ICs 1 | ||||
| IC1 | LM1458N | LM1458N | Operational amplifier, DIP8 | Can substitute JRC4559D (NJM4559D). |
| Potentiometers 4 | ||||
| GAIN | 1MA | A1M | 16mm right-angle PCB mount pot | Audio (log) taper. Jan Ray uses 500kB. |
| BASS | 50kC | C50k | 16mm right-angle PCB mount pot | Reverse audio (reverse log) taper. Jan Ray uses 50kB. |
| TREBLE | 50kB | B50k | 16mm right-angle PCB mount pot | Linear taper. Jan Ray uses 10kB. |
| VOLUME | 25kA | A25k | 16mm right-angle PCB mount pot | Audio (log) taper. Jan Ray uses 10kB. |
| Trimmers 1 | ||||
| BASS TRIM | 10k | 10k | Trimmer, 10%, 1/4” | Part of the bass trimmer mod. See build notes. |
| Switches 2 | ||||
| CLIP | SPDT cntr off | SPDT CNTR OFF | Toggle switch, SPDT center off | |
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| LEDs 1 | ||||
| LED | 5mm | 5MM | LED, 5mm, red diffused | |
| Jacks & sockets 4 | ||||
| IC1-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. |