JDX 48 Amplifier Direct Box User Guide CAUTION: Please read safety disclosure statement on the inside cover before connecting your Radial JDX 48. Radial Engineering Ltd. 1588 Kebet Way, Port Coquitlam BC V3C 5M5 Tel: 604-942-1001 Fax: 604-942-1010 email: info@radialeng.
CAUTION STATEMENT Please read before connecting your Radial JDX 48 THE JDX 48 IS NOT A LOAD BOX It is mandatory that your amplifier be connected to a loudspeaker or load box at all times. The JDX 48 does not provide a significant resistive load for an amplifier to safely operate. Damage may occur to your amp if the JDX 48 is used without a proper loudspeaker load. ALWAYS TURN YOUR AMPLIFIER OFF BEFORE CONNECTING OR DISCONNECTING THE JDX 48.
Radial JDX 48 Amplifier Direct Box Users Guide Table of Contents Page Design Concept.............................................................1 Applications...................................................................2 Feature Set....................................................................3 Signal Flow....................................................................4 Making Connections......................................................5 Using the JDX 48..............................
DESIGN CONCEPT The JDX 48 differs from a standard DI like the Radial J48. A standard DI taps the output of the guitar before it is connected to an amplifier. The JDX 48 taps the output of your amplifier yielding a completely different sound. The JDX 48 is placed between the amplifier and loudspeaker. A proprietary reactive circuit follows the constantly changing interaction between amp and speaker to capture the dynamic response of your amp.
TYPICAL APPLICATIONS Replace a Microphone with JDX 48: The most basic use of the JDX 48 is to eliminate the need to use an open microphone to capture the sound from the guitarist’s amp. The diagram shows the typical connection of the JDX 48. Using the JDX 48 with a Microphone: Mixing the signal from the JDX 48 with a microphone is a great way to create new sounds. The JDX 48 can also be mixed with a clean direct box signal for a cool effect.
Feature Set GROUND LIFT switch eliminates hum and buzz caused by ground loops. BASS EXT Boosts bottom end frequencies for bass. 300W AMP select for use with higher wattage amps. FROM AMP connection for amplifier output. TO SPEAKER connects your amp to the speaker through the JDX 48. Connection to a loudspeaker or a load box is mandatory. Please read the safety disclosure statement before connecting the JDX 48. XLR OUTPUT mic-level, 600Ω balanced XLR output connects to your mixing console.
Signal Flow To help you understand how the JDX 48 works take a few moments to trace the signal flow through the block diagram. TRANSFORMER REACTIVE LOAD FROM AMP ACTIVE BANDPASS FILTER ACTIVE BALANCED DRIVER BALANCED XLR OUTPUT POLARITY REVERSE TO SPEAKER GROUND LIFT Amplifier Input and Speaker Thru-put: The FROM AMP input and TO SPEAKER thru-put jacks are paralleled together and provides the means to patch the JDX 48 in-between the amp output and loudspeaker.
Making Connections The JDX 48 will typically be located near the guitar amplifier to facilitate short speaker cables. We recommend speaker cables be 3m (6') or less in length with a minimum of 16AWG two conductor cable. Longer cables should use heavier gauges to maintain the best power transfer. Before you begin, ensure your amplifier and PA or recording system are turned off. Lower all the volume controls to minimum to avoid loud transients. 1.
Using the JDX 48 After making connections use your amp and speaker cab as normal and set the amp volume to an appropriate level. Keep in mind that the output level of the JDX 48 (at the balanced XLR) will follow changes to the amp's volume so it’s best to set your amp up the way you like it before setting levels at the mixing console. When your amp is setup, turn up the preamp level at the mixing console. If you notice hum or buzz caused by ground loops, try pushing the GROUND LIFT switch inward.
Using With The Radial Phazer Combining a microphone with the JDX 48 can be very rewarding but to really go all the way, you have to consider the problem you have created by combining both sounds: The signal coming from the amp through the JDX 48 is traveling at the speed of light (via electron flow), while the corresponding sound arriving at the mic capsule via the speaker is travelling at the speed of sound.
Block Diagram TRANSFORMER REACTIVE LOAD FROM AMP ACTIVE BANDPASS FILTER ACTIVE BALANCED DRIVER BALANCED XLR OUTPUT POLARITY REVERSE TO SPEAKER GROUND LIFT JDX 48 Specifications Audio circuit type: . . . . . . . . . . . . . . . . . . . . . . Discrete Class-A - Transformer Isolated Frequency response: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shaped for guitar use Dynamic range: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THREE YEAR TRANSFERABLE LIMITED WARRANTY RADIAL ENGINEERING LTD. (“Radial”) warrants this product to be free from defects in material and workmanship and will remedy any such defects free of charge according to the terms of this warranty. Radial will repair or replace (at its option) any defective component(s) of this product (excluding finish and wear and tear on components under normal use) for a period of three (3) years from the original date of purchase.
