The core idea is a boost pedal and preamp built from premium analog discrete opamp circuitry, hand made in the USA, with studio features rarely found on a pedalboard: a transformer-coupled direct output on a balanced TRS connection, and a separate buffered tuner output1. Premier Guitar's reviewer described it as "essentially a highly tailorable preamp in a stompbox format"2.
What it does: a studio-style preamp in a stompbox
The PreDrive is meant to sit at the front of your board and stay on, refining and defining your tone before anything else touches it23. Rather than stacking gain like an overdrive pedal, it conditions the whole signal: the input and output knobs set the volume going into and out of the circuit, the drive knob mixes in harmonic content, and the boost footswitch adds up to 11 dB of extra body on demand13.
The studio heritage shows in the connections. The transformer-coupled direct out on a balanced TRS connection feeds digital effects, virtual amps, or a recording interface, and lets you record your guitar tone on a second channel so you can reamp it later or mix it with an effects-colored tone21. The buffered tuner output keeps a tuning feed available at all times1.
Pettyjohn describes the result as a studio grade, dual footswitch guitar preamp, and Pedal of the Day's reviewer called it "a pedal that refines and defines your tone. A great pedal for studio and/or live performances"13.
The controls
The face of the pedal holds five knobs, two mini toggles, and two footswitches2.
| Control | What it does |
|---|---|
| Input volume (top) | Sets the amount of volume going into the circuit1 |
| Drive mix (top) | Mixes in the amount of harmonic content (drive) added to the signal1 |
| Output volume (top) | Sets the amount of volume going out after the circuit1 |
| Boost gain (center, large) | Controls the gain volume of the boost stage; its large size makes it easy to fine tune on the fly23 |
| Low cut (small) | Sweeps from 20 Hz to 1 kHz2 |
| High cut (small) | Sweeps from 20 kHz down to 1 kHz2 |
| Vari-Z toggle | Matches input impedance to different pickup types1 |
| Harmonic drive toggle | Engages the vintage-voiced harmonic drive circuit and activates the drive knob; the preamp becomes slightly more mid-focused1 |
| Preamp footswitch | Engages the preamp section1 |
| Boost footswitch | Activates the boost, giving up to 11 dB of extra body3 |
The manual offers directions for two starting points: a touch-sensitive overdrive setting and a prescribed preamp setting2. Of the overdrive setting, Premier Guitar's reviewer wrote:
"I got a killer low-gain sound that's a dead ringer for a vintage amp cranked to 10"
With the boost on, driving the circuit into full saturation produces natural compression and rich harmonic content, reminiscent of a vintage tube amp driven to the edge of overdrive1.
Power and connections
The original PreDrive runs on 18V DC power, not the 9V most pedals use13.
The PreDrive requires an 18V DC power supply13. Players using standard 9V pedalboard supplies will need a dedicated 18V output or a step-up adapter.
The back panel carries the input jack, the 18V DC power jack, the output jack, the extra buffered tuner output, and the transformer-coupled direct output on a balanced TRS connection1. Premier Guitar's reviewer counted three outputs (output, direct out, and buffered tuner out) plus a single input on the top corner of the pedal2. The relic'd enclosure is bigger and more tank-like than an average stompbox2.
Boost and transparency
The boost stage maxes out at a considerable 11 dB of clean boost2. On transparency, Premier Guitar's reviewer was direct:
"Even at the highest boost levels, the PreDrive is among the most transparent boosts I have come across."
The reviewer found the boost adds very little coloration to your tone even at its highest settings, and noted that the boost knob's large size lets you fine tune the boost level on the fly very easily2.
History and versions
In 2017, Pettyjohn introduced the PreDrive Studio, which builds on the original PreDrive and Lift pedal offerings4. The Studio is a balanced-input and output studio-grade preamp with two 990-style discrete opamps based on the famed John Hardy 990 chip, sweepable HP and LP filters, a dual-rail power section with a 9V to 18V operation range, and true-bypass switching4. Its foot-switchable boost stage transparently increases the discrete opamp preamp gain by up to 30 dB with virtually no distortion or artifacts4. Pettyjohn also credits the PreDrive HW and the PreDrive Studio as the "audio parents" of the later Lift buffer/boost, usable on a vast array of instruments5.
Videos
ProGuitarShopDemos
Pete Thorn
Pettyjohn Electronics
Sources (5)
- Pettyjohn Electronics Introduces the PreDrive, Premier Guitar, 2014-06-02
- Pettyjohn Electronics PreDrive Review, Premier Guitar, 2014-10-14
- PettyJohn Electronics PreDrive, Pedal of the Day, 2015-01-22
- Pettyjohn Electronics Introduces the PreDrive Studio, Premier Guitar, 2017-03-08
- LIFT: Your Secret Weapon, Pettyjohn Electronics, 2019-01-14
