The Mozztronics TD-1 Tube Driver is an overdrive stompbox from the Australian builder Mozztronics, and it sets itself apart from most drives on a pedalboard by using a real 12AX7 tube in the gain stages of the circuit. Delicious Audio's Paolo De Gregorio describes it as "a stompbox featuring a real 12AX7 tube (used in the gain stages of the circuit)"1. Because the tube sits where the clipping happens, the maker's position is that the drive you hear is tube drive: "We here at Mozztronics use the tube where it is meant to be used, in the gain stages, so the drive you hear is tube drive"1.
The controls
The TD-1 keeps its faceplate simple: three knobs and one switch.
| Control | What it does |
|---|---|
| Gain | Controls the amount of overdrive, going from a light crunch to a searing screaming overdrive21 |
| Tone | Adjusts the brightness of the signal1 |
| Volume | Adjusts the overall output volume of the pedal1 |
| Contour | Three-position switch selecting between mild / normal / heavy1 |
Pedal of the Day's review found the spread of settings wide for such a small panel: "The range of sounds from these 4 simple controls is impressive, and that warm real-tube sound shines through at every po"2. The same review described the pedal in characteristically blunt terms as "this orange menace will give you instant valve amp sound", a nod to its orange enclosure2.
Power: 15VAC to 16VAC
This is the one specification that shapes where the TD-1 can live on a board. It is powered from an external 15VAC to 16VAC supply with a 2.1mm plug21. That is alternating current rather than the direct current most pedalboard bricks put out, so a standard daisy chain or battery will not run it. It needs its own dedicated supply.
The TD-1's 15VAC to 16VAC alternating-current requirement will not run from the DC outputs of a standard pedalboard supply. Plan a dedicated AC supply output for it if you add it to a board.
Starved plate mode and the tube
The TD-1 runs its 12AX7 in starved plate mode, meaning the tube operates at a reduced plate voltage compared with an amplifier's, while still being a genuine tube in the signal path21. Pedal of the Day put it plainly: "this pedal runs the tube in starved plate mode, for that real tube sound"2. The tube is used in the gain stages, so the drive you hear is all tube drive2.
The TD-1 and the TD-2 HV Tube Driver
Mozztronics also offers a sibling pedal, the TD-2 HV Tube Driver3. The TD-1 carries four controls, and the maker is explicit about where the tube sits in the circuit: "We here at Mozztronics use the tube where it is meant to be used, in the gain stages, so the drive you hear is tube drive"1.
What reviewers said
Both write-ups were positive. Mozztronics quotes the SuperFunAwesomeHappyTime Pedal Show's verdict on its own page: "The guys at the SuperFunAwesomeHappyTime Pedal Show are a big fans of the TD-1 Tube Driver"1, and the Pedal of the Day review praised the range of sounds available from the four controls and the warm real-tube sound that held up across settings2.
Videos
TheSuperFunAwesomeHappyTimePedalShow
Pedal of the Day
Questions
Does the Mozztronics TD-1 Tube Driver use a real tube?
Yes. Delicious Audio describes it as a stompbox featuring a real 12AX7 tube, used in the gain stages of the circuit. Because the tube sits in the gain stages, the drive you hear is tube drive rather than a solid-state circuit with a tube added elsewhere in the signal path.
What does the Contour switch do on the TD-1?
The CONTOUR switch is a three-position switch that selects between mild, normal and heavy. It sets the overall character of the drive, and the Gain knob then controls the amount of overdrive within that setting, from a light crunch to a searing screaming overdrive.
Can I run the TD-1 on a 9V battery or standard pedalboard supply?
No. The TD-1 is powered from an external 15VAC to 16VAC supply with a 2.1mm plug. That is an AC voltage, not the 9V DC that most pedalboard power supplies and daisy chains provide, so it needs its own dedicated supply.
What does starved plate mode mean?
Starved plate mode means the tube is run at a lower plate voltage than it would see in an amplifier. The TD-1 runs its 12AX7 this way, which Pedal of the Day credits with delivering that real tube sound from a pedal-sized circuit running on an external supply.
What is the difference between the TD-1 and the TD-2 HV Tube Driver?
Both are Mozztronics tube drivers using a 12AX7 in the gain stages and both run on 15 to 16VAC. The TD-2 HV Tube Driver is the later sibling, featured by Pedal of the Day in May 2022, with a three-knob control set. The TD-1 uses four controls including a three-position CONTOUR switch.
Sources (3)
- Mozztronics TD-1 Tube Driver, Delicious Audio, 2018-07-30
- Mozztronics TD-1 Tube Driver Overdrive, Pedal of the Day, 2021-01-02
- Mozztronics TD-2 HV Tube Driver, Pedal of the Day, 2022-05-04
