JDI MK3

Professional Passive Direct Box with Jensen Transformer

Overview

The JDI Mk3 from Radial Engineering is a professional, passive direct box that converts hi-impedance instrument signals to a balanced low-impedance output, allowing long cable runs without noise. The unit is ideally suited for all instruments including keyboards, bass guitar and acoustic guitars for use in studio, broadcast and live sound reinforcement. Because of the transformer, the JDI provides 100% isolation between the instrument input side and the balanced output, eliminating hum and buzz caused by ground loops. Passive DIs that use inexpensive iron or steel core transformers can degrade sound through phase shift at various frequencies, a phenomenon known as group delay. This has the effect of making bass sound indistinct, causing the mid-range to smear and lack punch. The JDI employs a Jensen transformer with a nickel-laminated core which does not retain a memory or polarity. This reduces phase distortion, improves linearity and lowers harmonic distortion. A 15dB pad is provided for high level instruments to avoid input distortion. A merge switch converts the thru output to a second input, allowing two signals, such as those from a stereo keyboard, to be summed to mono when input channel availability is limited. The unit is built to withstand the abuse of the road. The book-cover design features an internal 14-gauge steel skeleton that is corner welded to ensure the internal electronics will never be subjected to outside stress. The military grade PC board is mounted on steel pem nuts and the whole is then enclosed in a second steel casing. The passive design requires no power source.

Features

• Phase coherent professional direct box with 100% passive design and Jensen Transformer equipped

• Ultra linear performance from 10Hz to 40kHz

• Dual function inputs with two-channel merge

• Polarity reverse, ground lift and pad switches

• Ultra-durable welded steel chassis with double sided printed circuit board

• No-slip bottom pad and protective channel for switches

• Ideal for acoustic guitars and basses, keyboards, modules and electronic drums

Specifications

 Input Connections 1 x 1/4" TS phone

Output Connectors 1 x XLR

1 x 1/4" TS phone Thru

Input Level +19dB

Output Level Not specified by manufacturer

Controls -15dB pad

Polarity reverse

Ground lift switch

Merge of Input and Thru

Parallel 12" speaker emulation switch

Frequency Response 10Hz to 40kHz

Noise SNR: 119dB

Power Passive

Specialties Merge function converts the input and thru

output jacks to left and right inputs and

mixes them to mono at the XLR

Packaging Info

Dimensions (WxDxH) 6 1/2" x 4" x 3" (shipping) Weight 1.92 lbs (shipping)

What’s in the Box

-  JDI MK3