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Rental Radial JDI Duplex Passive Direct Box

The JDI Duplex from Radial Engineering is a two channel version of the JDI passive direct box that converts hi-impedance instrument signals to two balanced low-impedance outputs, 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 transformers, 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 Jensen transformers with a nickel-laminated core which do not retain a memory or polarity. This reduces phase distortion, improves linearity and lowers harmonic distortion. Each channel provides a 15dB pad for high level instruments to avoid input distortion. Merge switches convert the thru outputs 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.

Dual channel, 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 per channel
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

Radial Engineering JDI Specs

Input Connections 2 x 1/4" TS phone
Output Connectors 2 x XLR
2 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
Dimensions (WxDxH) 8 1/2" x 5 7/8" x 3 1/4" (shipping)
Weight 3.15 lbs (shipping)
Specialties Merge function converts the input and thru output jacks on each channel to left and right inputs and mixes them to mono at the XLR outputs