ZEQD-Pre™ - The All-Analog Simulation Solution

A collaboration between EarthQuaker Devices and Dr. Z Amplification

This all-analog tube preamplifier brings together EarthQuaker Devices’ innovative pedal design and Dr. Z Amplification’s decades of tube amp expertise. With a passive three-band EQ, professional headphone output, balanced XLR output, and onboard analog cabinet simulation, the ZEQD-Pre delivers authentic tube warmth and dynamic response in a complete analog amplifier system that fits right on your pedalboard.

The ZEQD-Pre uses the EF86 pentode—the same tube that gives many Dr. Z amplifiers their pristine hi-fi tone and makes them such responsive pedal platforms.

The Technical Side

Unlike the common 12AX7 triode (two elements plus cathode), the EF86 pentode has four internal elements plus cathode. This structure yields measurably superior performance:

• Gain Factor of 185: Significantly higher than comparable triodes

• 44V RMS Output: Substantial voltage swing for enhanced dynamics

• Extended Frequency Response: Full-spectrum clarity from deep lows to detailed highs

What This Means for You

These specifications translate directly to playing experience:

• Touch Sensitivity: The EF86 responds to every dynamic nuance in your playing. Play lighter and it cleans up; dig in and it blooms. Natural expression that follows your hands.

• Full-Frequency Clarity: Extended response means harmonic richness without sacrificing definition. Bass notes stay tight, highs remain bell-like and clear.

• Responsive EQ: Higher voltage and broader bandwidth let the passive Three-Band EQ shape your tone effectively with minimal signal loss. The interactive controls behave like classic tube amp tone stacks—predictable and musical across their entire sweep.

The EF86 brings hi-fi performance to tube preamplification while staying responsive and musical.

Technical Specifications

Dimensions
5.88 x 3.94 x 2.75 in. (149 x 100 x 70 mm) with knobs

Current Draw
500 mA

Input Impedance
10 MΩ

Output Impedance
Variable

Headphone Out Impedance
39 Ω

Direct Out Impedance
100 Ω

Switching
ZEQD-Pre uses mechanical true bypass switching.

Power
This device takes a standard 500 mA (or higher) 9-volt DC power supply with a 2.1 mm negative-center barrel. We always recommend pedal-specific, transformer-isolated wall-wart power supplies or multiple isolated-output supplies. Pedals will make extra noise if there is ripple or unclean power. Switching-type power supplies, daisy chains, and non-pedal specific power supplies do not filter dirty power as well and let through unwanted noise. DO NOT RUN AT HIGHER VOLTAGES!