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Q: Is a flat frequency response better than a colored response?

A: This is a good question. When buying a large condenser microphone, you are most often not getting a flat response mic, 

but a mic colored or flavored to add to your sound palette. Most studios boast a selection of mics and the sign of a good 

engineer is one that knows ‘which mic to use on what’ in order to get a particular tone.

With direct boxes, this is usually not the case. If the sound of the guitar is not right, one will usually change the guitar, not 

the direct box, therefore we believe the role of the direct box is to transport the original signal as faithfully as possible from 

the instrument to the destination and allow the engineer and producer to make the artistic choices. Here’s more food for 

thought… should the direct box change the tone of the instrument? If it makes your Strat sound fat, will it make your Les 

Paul muddy? We think a properly designed DI should be faithful to the source. The Radial JDI direct box gives the engineer 

and producer a natural and uncolored sound to work with.

Q: What about tube direct boxes?

A: Tube direct boxes are cool and there is a definite place for them in the recording world. Tube DI’s introduce personality 

to the sound and should be viewed in the same way as one views a tube microphone.

Q: If my JDI ever fails, what do I do?

A: In the past 10 years the JDI has been so reliable that it is a rare occurrence when we need to repair one. If however 

something goes bad, a switch for example, simply call Radial and we will issue a return authorization number for you to 

send it back to us for repair. We do suggest that before you do so, visit the dealer where you bought it and have them check 

it out before sending it away. Often times, it turns out that bad cables are the actual problem.

Q: What is the warranty on the JDI?

A: The  Radial JDI carries a 3-year warranty while the Jensen

®

  transformer inside carries a 20-year warranty. Repairing 

the transformer can be done either through Radial or directly with Jensen Transformers. 

Q: Can I rack-mount the Radial JDI?

A: Yes. This is easily done with the Radial J-Rak. The J-Rak is a 2RU shelf that holds as many as 8 Radial small format 

direct boxes, like the JDI or J48 which can be front or rear-mounted depending on your intended application. 

Q: Can I rack-mount the Duplex?

A: No. The Radial JDI Duplex is designed as a stand-alone device. If you are looking for a rackmount solution that takes up even 

less space than the J-Rak, the 1-RU Radial JD6 may be your solution with 6 JDI channels in 1 RU space.

Radial Engineering   

 

      JDI User Guide

14

True to the Music

Содержание JDI Mk3

Страница 1: ...g 1638 Kebet Way Port Coquitlam BC V3C 5W9 tel 604 942 1001 fax 604 942 1010 email info radialeng com web www radialeng com Radial Engineering is a division of C TEC JP CableTek Electronics Ltd JDI and www radialeng com DUPLEX Mk3 ...

Страница 2: ... your JDI 11 7 Frequently asked questions 12 8 Block diagram and specifications 15 Warranty Back cover Radial Engineering 1638 Kebet Way Port Coquitlam BC V3C 5W9 tel 604 942 1001 fax 604 942 1010 email info radialeng com web www radialeng com Radial Engineering Ltd is a division of C TEC JP CableTek Electronics Ltd Features and specifications are subject to change without notice ...

Страница 3: ...on or crosstalk For simplicity this manual will discuss the JDI All features and functions on the Duplex are identical to those of the JDI Both direct boxes employ the Jensen JT DBE transformer for unmatched audio performance exceptional noise rejection and high signal handling This makes them ideal for acoustic guitar bass and keyboards In fact just about any audio signal is transformed gracefull...

Страница 4: ...formance 7 Full bottom no slip pad reduces slipping in use and provides mechanical and electrical isolation 8 Double sided PC board military grade circuit board features a full ground plane for maximum protection against stray magnetic fields and RF noise 9 XLR output connector wired to the AES standard with pin 1 ground and pin 2 hot provides a balanced 150 Ohm mic level signal 10 POLARITY switch ...

Страница 5: ...dio transformer should be able to handle most instrument signal levels without distortion At exceptionally high signal levels the 15dB pad should be used to reduce the input level to the transformer If you hear distortion simply depress the 15dB pad button If you intend to use the JDI in parallel with a speaker load it is important that you read the details on this application in the Part 5 Featur...

Страница 6: ...eproduce the most accurate picture of the source no matter what the instrument Direct boxes perform the important function of impedance matching and signal balancing This means that they take the high impedance output from a guitar or keyboard and transform it to the low impedance signal used in balanced sound systems Balanced signals inherently cancel noise and due to their lower impedance can tr...

Страница 7: ...s a mic level signal This allows the JDI to be used alongside other microphone signals without introducing cross talk or causing transformer saturation when driving the signal through the mic bridging transformers of a splitter The magic of a great transformer The Radial JDI is a passive direct box this means that it employs a transformer to convert the impedance and balance the signal At Radial w...

Страница 8: ...nd buzz An audio laboratory test called The Green Report visit www radialeng com for details pitted the JDI against three other direct boxes commonly used in professional audio The tests showed that the JDI could handle more gain before distortion was more linear throughout the audio frequency range and showed significantly less phase distortion All boxes tested well at 1kHz but as the frequency dr...

Страница 9: ...ruments such as acoustic guitar to be connected to the DI and then to the snake system using the Lo Z XLR output splitting the signal to feed the stage monitor mixer for foldback just as microphones are In this case the thru jack would not be used The MERGE switch The JDI features an innovative merge function that turns the input and the thru put into a left right to mono mix Depressing the merge ...

Страница 10: ...d Connection is made to the mic level input of the mixing console or to a standard mic pre amplifier The JDI is ideally suited for interface with concert snake systems and splitters where mic and direct box signals are directed to several destinations at the same time such as recording monitor broadcast and front of house mix positions The POLARITY switch A polarity reverse toggles the XLR pin 2 an...

Страница 11: ... at the mixing console If you are using the thru put to your personal amp then your amp and the mixer will have ground paths and lifting the ground would then be considered Parallel speaker connection and the SPEAKER switch IMPORTANT THE JDI IS NOT A LOAD BOX You must ensure that the amplifier is connected to it s speaker load first as the JDI is not designed to handle the load on its own There are ...

Страница 12: ...ctors and an external book end design steel shell designed to protect the switches and jacks from overzealous roadies and other rigors of touring Both boxes are made from 14 gauge steel and protected by a heavy baked epoxy finish that will look great even after years of service Inside the mil spec PC board is two sided which means that all components are soldered twice Further the dual shell enclos...

Страница 13: ...put using a female to female XLR turn around adaptor Keep your level down to ensure the signal will not overload the JDI s transformer Connect the input of the JDI to the input of the guitar amplifier and you are set to go Use the Radial JDI for long cable runs High impedance coax cables are susceptible to noise if they exceed 25 feet Balanced lines on the other hand split the signal into two low i...

Страница 14: ...s such as phase distortion Best of all passive DI s eliminate ground loops Q Why do people use active direct boxes A There are two reasons that active DI boxes like the Radial J48 have become popular To get good sound with a passive direct box you need to use a high quality transformer like a Jensen which can be quite expensive This cost dissuades many manufacturers from building passive DI s a ba...

Страница 15: ... typically 48 volts and about 5mA When phantom is on it will not harm the JDI Q What is phase distortion A Keeping your signal in phase is akin to making sure that when you play guitar the sound coming from the low E string plays at the same time as the G string as they come out of your amp You may take this for granted but the fact is phase distortion can cause an instrument to get lost in the mi...

Страница 16: ...duce personality to the sound and should be viewed in the same way as one views a tube microphone Q If my JDI ever fails what do I do A In the past 10 years the JDI has been so reliable that it is a rare occurrence when we need to repair one If however something goes bad a switch for example simply call Radial and we will issue a return authorization number for you to send it back to us for repair...

Страница 17: ...ced 140k Ohms typical Output impedance Balanced 150 Ohms typical Frequency response 10Hz to 40kHz Linear performance 0 22 dBr deviation 20kHz Total harmonic distortion 0 05 20Hz 0 005 1kHz Phase distortion 4º at 20Hz 0 3º at 1kHz CMR 100dB 60Hz Maximum input level 22dBu Size 3 5 wide 2 high 5 5 deep Weight 1kg 2 2lbs Construction Welded 14 gauge steel Finish Baked enamel finish JDI Block Diagram ...

Страница 18: ...laim under this limited warranty the product must be returned prepaid in the original shipping container or equivalent to Radial or to an authorized Radial repair center and you must assume the risk of loss or damage A copy of the original invoice showing date of purchase and the dealer name must accompany any request for work to be performed under this limited warranty This limited warranty shall...

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