Hazelrigg Industries 4DI DI BOX

The Hazelrigg Industries 4DI is a premium 4-channel all-tube direct injection box, based on D.W. Fearn's classic VT-I/F design. Housed in a rugged 2U rackmount chassis, it delivers warm, harmonically rich DI tone for electric instruments, synths, and acoustic pickups. Each channel features a front-panel locking 1/4'' input, rear-panel passthrough, XLR mic-level output, and a ground lift switch with LED indicator. Handcrafted in the USA, the 4DI is ideal for both studio and live setups, offering high headroom, low distortion, and unmatched sonic depth.

• True All-Tube Signal Path: Each channel uses a premium vacuum tube circuit based on the legendary D.W. Fearn VT-I/F design for deep, rich analog tone.

• Four Independent DI Channels: Perfect for handling multiple instruments simultaneously in studios, live sound setups, or houses of worship.

• Instrument-Level Inputs Front & Rear: Locking 1/4'' inputs on the front and mirrored pass-through jacks on the rear provide flexible routing options.

• Transformer-Balanced Mic-Level XLR Outputs: Delivers warm, low-noise, mic-level signals designed to match 150-ohm professional preamps.

• Massive Headroom and Detail: Captures full dynamic range from electric bass, guitar, synths, and acoustic instruments with pickups - without harshness.

• Ground Lift Per Channel: Each input has its own locking ground lift switch with LED status to help eliminate hum and buzz in complex setups.

• Built for the Stage and Studio: Housed in a rugged all-steel 2U rack chassis, designed for professional use under demanding conditions.

• Handcrafted in the USA: Carefully assembled and tested by hand to ensure consistency and sonic excellence.

GENERAL OVERVIEW:

• 4-channel all-triode vacuum tube direct injection (DI) box

• Based on D.W. Fearn's classic VT-I/F design

• Part of Hazelrigg Industries' Solution Series (with VNE, VLC, VEC, and VDI)

• Designed for use in studios, live FOH, and houses of worship

• Handcrafted in the USA with premium-grade components

AUDIO CIRCUITRY:

• Pure analog vacuum tube signal path using selected 6072 or 12AY7 triodes

• Each channel features independent DI circuitry

• Custom Jensen transformer-balanced mic-level output

• Cathode-follower output stage with capacitive coupling for optimum isolation

• Input impedance: 1 M ohm

• Output impedance: Matches 150 ozhm mic inputs

INPUT AND OUTPUT SPECIFICATIONS:

• Inputs: 4 front-panel locking 1/4 in mono instrument jacks

• Pass-through: 4 rear-panel 1/4 in parallel input/thru jacks

• Outputs: 4 rear-panel gold-plated XLR mic-level balanced outputs (pin 2 hot)

• Gain: -10 dB

• Max input level: 2.3 V peak-to-peak (1% THD)

• Frequency response: 10 Hz - 20 kHz +/-0.2 dB

• THD+N: < 0.3% (20 Hz - 20 kHz)

• Intermodulation distortion: < 0.01% SMPTE

• Noise: -90 dB below output (22 Hz - 22 kHz bandwidth)

• Max output level: -12 dBm nominal

FRONT PANEL FEATURES:

• 4 locking 1/4 in instrument inputs

• LED indicators per channel (signal and ground lift status)

• 4 ground lift switches (locking toggle style)

• Power switch with integrated red pilot light

• Fully regulated power supplies for filament and plate voltages

REAR PANEL FEATURES:

• 4 gold-plated XLR mic-level outputs

• 4 input/pass-through pairs (1/4 in TS jacks)

• GND terminal for external grounding schemes

• IEC power inlet with voltage selector (115V / 220V)

• Fuse: 1A (115V) / 0.5A (220V)

MECHANICAL AND POWER:

• Rackmount: 2U height (3.5 in), all-steel construction

• Dimensions: 6.25 in W - 2.25 in H - 9.5 in D (15.9 - 5.7 - 24.2 cm)

• Weight: 14 lbs (6.35 kg)

• Power: 120/220 VAC 50/60 Hz, 25 W

• Suggested warm-up: 5 minutes for optimal performance

MAINTENANCE:

• Tubes: 4 - 6072 / 12AY7 (user replaceable, matched for low noise and microphonics)

• Tube life: multiple years, tested for noise and microphonics

• Filter capacitors rated for >20 years

• User-replaceable with manufacturer-recommended parts

APPLICATIONS:

• Electric and acoustic guitars/basses with pickups

• Electric pianos, synthesizers, samplers

• Suited for studio recording, live sound reinforcement, and broadcast scenarios

• Compatible with any professional mic preamp; optimized for VT-1, VT-2, and VLC