The LEECUSTOM 12AX7PRE (Black) is a compact vacuum tube-based preamp and booster pedal from LEECUSTOM, built around a 12AX7/ECC83 triode tube. It is an all-tube amplification stage with tone controls and internal band-frequency switches, and RockBoard's PedalPedia says the tube gives it "a warm, amp-like dynamic response and natural overdrive characteristic"1. Players use pedals like this in two ways: as a clean or pushed boost in front of an amp, and as a preamp stage of its own, in the territory covered by preamp pedals and boost pedals.
The tube and the circuit
The heart of the pedal is a 12AX7/ECC83 triode tube, the tube type found in the preamp stages of countless guitar amplifiers. RockBoard's PedalPedia describes the amplification stage as all-tube, and the circuit type as analog, so the signal is never converted to digital at any point1. Because the tone comes from an actual tube rather than a model of one, the maker's description of a warm, amp-like dynamic response and natural overdrive characteristic follows from the design: the tube responds to playing dynamics the way an amp preamp does1.
Controls
| Control | What it does |
|---|---|
| Treble | Tone control for high frequencies1 |
| Bass | Tone control for low frequencies1 |
| Volume | Overall output level1 |
| Internal band-frequency switches | Set the pedal's frequency bands internally1 |
The three front-panel knobs cover the everyday tone shaping, while the internal band-frequency switches sit on the circuit board side of the design and set how those bands are defined1.
RockBoard's PedalPedia lists the current draw at 500mA at 9V DC, center negative1. That is well beyond what a battery or a shared daisy-chain output can supply, so the 12AX7PRE needs its own power supply output rated for the full 500mA.
Questions
Does the LEECUSTOM 12AX7PRE use a real vacuum tube?
Yes. According to the maker's product information, the pedal is built around a 12AX7/ECC83 triode tube, the same tube type long used in guitar amplifier preamp stages. The amplification stage is all-tube, and the maker says this gives the pedal a warm, amp-like dynamic response and a natural overdrive characteristic.
What are the internal band-frequency switches for?
The 12AX7PRE has internal band-frequency switches alongside its external Treble, Bass and Volume controls. The maker's product information lists them as part of the pedal's tone-shaping features, letting the player set the pedal's frequency bands internally while the front-panel knobs handle everyday tone adjustments.
How much current does the LEECUSTOM 12AX7PRE draw?
The maker lists the current draw at 500mA at 9V DC, center negative. That is far more than a typical analog pedal needs, so it rules out running the 12AX7PRE from a battery or sharing a low-current daisy-chain output; it needs its own supply output rated for the full 500mA.
Is the LEECUSTOM 12AX7PRE analog or digital?
The maker lists the circuit type as analog. Combined with the vacuum tube at its core, the pedal is an entirely analog signal path with no digital processing.
Sources (1)
- 12AX7PRE (Black) by LEECUSTOM, RockBoard PedalPedia, 2026