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Compact metal passive direct box with rubber base

Radial Engineering

Radial Engineering RAD-PRODI Passive Direct Box

SKU CH-3FMS-JY3P7

Single-channel passive direct box with custom transformer, -15dB pad and ground-lift switch for acoustic guitar and bass

  • Recorder typeVideo Recorder
  • Custom transformer eliminates noise for clean signal
  • 15dB pad handles high-output sources without distortion
  • Ground lift switch removes ground-loop hum instantly
  • Passive design needs no external power for simple setup
  • Rugged 14-gauge I-beam chassis withstands stage abuse

Single-channel passive direct box

The Radial Engineering RAD-PRODI is a single-channel passive direct box built for acoustic guitars and bass guitars. It suits live sound and studio work where a clean, balanced signal is needed without external power. Musicians and engineers who want transformer isolation in a compact unit will find it practical. It is not for users needing active buffering or multi-channel routing.

Transformer headroom and pad

A custom-wound transformer delivers an exceptionally linear response from 20Hz to 18kHz and handles high signal levels without saturation. A -15dB pad accommodates hotter sources such as active pickups or line-level devices. The passive design adds no noise of its own but cannot boost a weak instrument signal. Users requiring gain or impedance matching for very low-output sources must look elsewhere.

Rugged chassis and ground lift

A 14-gauge welded I-beam inner chassis and outer shell protect the circuit board from torque stresses. A full-bottom no-slip rubber pad provides electrical insulation and keeps the box stationary on stage or desk. A ground lift switch breaks ground loops to eliminate hum. The unit has no rack ears or mounting holes, so permanent installation requires an external tray or shelf.

How it compares

Measured against everything we stock in NVR & DVR Recording Systems, at today’s prices. Recalculated every night.

Price $108.99
Cheaper than about 70% of the 246 comparable items (median $272.99).

Specifications

Product
Recorder typeVideo Recorder

Questions about this item

Will the ProDI's passive design work with the piezo pickup on my older acoustic guitar without needing a battery or power supply?

Yes, the passive circuit requires no external power, so it connects directly to a piezo pickup and sends a balanced mic-level signal to the mixer.

How can I confirm the custom-wound transformer is delivering the specified 20Hz to 18kHz response after I connect it?

Run a frequency sweep from a test source through the ProDI and measure the output; the response should stay linear across the 20Hz to 18kHz range with very low harmonic and phase distortion.

Does the box include the 14-gauge welded I-beam chassis and no-slip rubber pad, or are those separate accessories?

The 14-gauge welded I-beam inner chassis and full-bottom no-slip rubber pad are built into the unit; nothing extra is needed for mounting or shock protection.

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