DI Box
Definition
A Direct Injection (DI) box converts a high-impedance, unbalanced signal (from instruments like electric guitar, bass, or keyboards) to a low-impedance, balanced signal suitable for connection to a microphone preamp or mixing console. DI boxes also typically include a ground lift switch to eliminate Ground Loop hum.
Context
“What is a DI and when do I need one?” is a recurring newbie-questions topic. The short answer: whenever you want to plug an instrument directly into your audio interface or console without going through an amplifier.
Types
- Passive DI — uses a transformer, no power required, handles high-level signals well. Good for active instruments (keyboards, active bass)
- Active DI — uses electronics (requires battery or phantom power), better for low-output instruments (passive guitar pickups). Provides cleaner signal with passive pickups
- Tube DI — adds warmth/harmonic coloring. Premium options like the A Designs REDDI are studio staples
Common Uses
- Bass guitar recording — DI + amp mic is the standard professional approach (see Bass Recording)
- Guitar Reamping — record a clean DI signal to re-amp later through different amps
- Keyboards/synths — DI provides balanced, noise-free connection to the console
- Ground loop elimination — the ground lift switch breaks hum-causing ground loops
Popular Models
- Radial JDI (passive) — industry standard (see Radial DI)
- Radial J48 (active) — popular for passive instruments
- Countryman Type 85 — studio classic
- A Designs REDDI — premium tube DI