The Pettyjohn Electronics PreDrive Studio is a fully analog preamp, buffer and EQ pedal aimed at studio and stage use, announced on March 8, 2017. Pettyjohn describes it as "the absolute pinnacle of studio grade guitar pedals" and claims "there isn't a more detailed or musical buffer/boost preamp or EQ on the market today"1. It sits among preamp pedals and doubles as a buffer and boost.
Circuit and design
At the heart of the PreDrive Studio are two studio-grade discrete opamps, described by Pettyjohn as "top shelf 990 style Discrete Opamps" based on the famed John Hardy 990 chip1. The company says the design draws on knowledge pioneered by the world's first discrete opamp based guitar pedal, the original PreDrive1. The pedal later became an influence within the company's own range: a 2019 blog post describes the LIFT as sharing its audio parents, the PreDrive HW and the PreDrive Studio, and notes the LIFT "can be used on a vast array of instruments"2.
Controls
The PreDrive Studio carries six controls covering gain, filtering and output level1.
| Control | What it does |
|---|---|
| Input Gain | Controls input buffer operation level from a unity buffer to 6 dB of gain |
| Lows | Wide-range sweepable low cut filter, sweeping from 20 Hz to beyond 1 kHz with a 6 dB per octave slope |
| Highs | High-cut filter using the famed Auricap, sweeping from 22 kHz down to 1 kHz with a gentle 6 dB per octave slope |
| Boost Gain | Foot-switchable boost stage that increases the discrete opamp based preamp gain up to 30 dB with virtually no distortion or artifacts |
| Output trim (top middle) | Adjusts the level of the output buffer amp, trimming the operating level of both outputs at once |
| Output Level (top left) | Controls the level of the unbalanced output, independent of the balanced out level |
Balanced connections and power
The Studio version's defining feature is its connectivity. It offers fully balanced in and out connections via TRS, along with standard unbalanced connections1. The input can be selected as standard unbalanced for instruments, or switched to a line level balanced input accepting balanced signals from an interface, patch bay, recording console, or microphone1. On the output side, the lower left TRS jack continuously mirrors the unbalanced output, including EQ and Gain settings, with true -10/+4dB operation1. Pettyjohn states that "the balanced output continuously mirrors the unbalanced output without any tonal change"1.
The pedal runs on a dual-rail power section with a 9V to 18V operation range and draws around 50mA1. A supply able to deliver that current at the chosen voltage is required.
Background and where it is made
Pettyjohn Electronics announced the PreDrive Studio from Albany, Oregon, on March 8, 20171. The company states the box and circuit are "Handmade in the beautiful Pacific Northwest, USA"1. The pedal builds on the original PreDrive and Lift pedal offerings in the company's range1.
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Questions
What is the difference between the PreDrive Studio and the original PreDrive?
The PreDrive Studio builds on the original PreDrive and Lift pedal offerings, drawing on knowledge pioneered by what Pettyjohn calls the world's first discrete opamp based guitar pedal. The Studio version adds fully balanced TRS input and output connections alongside standard unbalanced ones, true -10/+4dB operation on the balanced output, and two sweepable filters, all in a fully analog design built around two 990-style discrete opamps.
Does the PreDrive Studio have balanced outputs?
Yes. The PreDrive Studio offers fully balanced in and out connections via TRS, along with standard unbalanced connections. The balanced output continuously mirrors the unbalanced output without any tonal change, including EQ and Gain settings, with true -10/+4dB operation. The input can also be switched to a line level balanced input accepting signals from an interface, patch bay, recording console, or microphone.
How much current does the PreDrive Studio draw?
Pettyjohn Electronics states the PreDrive Studio draws around 50mA. It runs on a dual-rail power section with a 9V to 18V DC operation range, so a supply capable of meeting that current draw at the chosen voltage is needed.
Is the Pettyjohn PreDrive Studio true bypass?
Yes. The PreDrive Studio uses True-Bypass Switching, so when the pedal is off, the signal passes through without passing through the preamp circuitry.
Where is the PreDrive Studio made?
Pettyjohn Electronics states that the box and circuit are handmade in the Pacific Northwest, USA. The company announced the pedal from Albany, Oregon, in March 2017.
Sources (2)
- Pettyjohn Electronics Introduces the PreDrive Studio, Premier Guitar, 2017-03-08
- LIFT: Your Secret Weapon, Pettyjohn Electronics, 2019-01-14
