Q: What is a direct box anyway?
A: A direct box is an impedance matching and signal-balancing device. DI's convert hi-impedance instrument signals to mic-level balanced lines for interface with pro-audio equipment such as mixing consoles. A good direct box will ensure proper electrical signals are maintained throughout the signal chain and allow long cable runs without added noise. A good DI box is just as important as a good microphone.

Q: What is the difference between active and passive direct boxes?
A: Active direct boxes require power such as a separate power supply, 48V phantom power, or a battery to activate their circuits while passive direct boxes convert the signal from high-Z to low-Z using only a transformer. Passive DI's do not require a power supply to work.

Q: I heard active direct boxes are better?
A: This can be thought in terms of a dynamic mic compared to a condenser mic. There are good dynamic mics and there are good condenser mics. A good passive direct box depends entirely on the transformer that is being used. For instance, the Radial JDI uses the world's finest transformer, a Jensen. These DI's sound fabulous! In fact way better than most active direct boxes!

Q: If the JDI is so good, why should one buy the JDV over the JDI?
A: It comes down to the application. For keyboards, and simple live set-ups, the JDI is fantastic. No power supply, no batteries to go dead. You just plug it in and it sounds great. The JDV on the other hand will give you more reach. You will enjoy more detail or as Khaliq Glover (Engineer for Marcus Miller and Herbie Hancock) said: “the JDV is almost holographic compared to the single dimension of most DIs.”

Q: Can I power the JDV with the 48V phantom on my console?
A: No. Typical 48V phantom power only has 5 milliamps of available current. The JDV requires much more current than this to drive its 30 Volt rails. Phantom power is simply unable to do the job.

Q: Why would I buy the JDV over other active direct boxes?
A: Sound quality. There is nothing on the planet that will do a better job than the JDV. It is designed from the ground up to be sonically pure, exceptionally dynamic, and totally transparent. The combination feed-forward design, class-A circuit and 30 volt internal rails combine to put the JDV in a class of its own.

Q: Why is Class-A considered best?
A: Class-A circuits do not employ multiple gain stages to achieve greater efficiency. They are pure gain stages that have and continue to be the choice for audiophiles and purists. Although more efficient, Class-B or AB circuits suffer a problem called zero-cross distortion that Class-A devices do not. In the JDV, we are not concerned about power-per-watt output, we are only concerned about getting the best possible sound. We go a step further in employing a unique feed-forward design.

Q: What is a feed-forward design?
A: The 'easy guide' to circuit design always includes a feedback loop in the circuit to stabilize the circuit. The JDV does not take the easy way out; there is no feedback loop. The JDV circuit is akin to a pure tube circuit design. The result is razor sharp precision without overshoot, ringing or rounded-off wave generation. This things is almost alive!

Q: The overload LED never goes on. Why?
A: Because the JDV has such a huge internal rail voltage, instruments are typically unable to drive sufficient current into the JDV to cause it to overload. Kinda' like having 12 cylinders on a car. You don't need them until you are racing. Kick 'em in and the extra horsepower makes all of the difference!

Q: Can I overload the JDV's input?
A: We could only get the JDV input to overload when we drove the output from the line level of a mixer directly into the JDV and turned the volume up high. It is unlikely, under normal use, that you will ever overload the JDV.

Q: Can I connect a guitar amp head to the JDV without speakers?
A: No. The JDV is not a load box. This means that you must connect the amp to a load 1st (like a speaker) and then you can connect the JDV to the load.

Q: Can I connect a guitar amp head to the JDV with a load box?
A: Yes. However you should be careful to ensure that the load box properly emulates a speaker. Make sure the -30dB pad is engaged and monitor the JDV's input to make sure the overload LED does not go on.

Q: What level is the JDV output?
A: The JDV is a unity gain device. This means that although it is designed to output a mic level signal, the output can be significantly higher depending on what input is being sent to it. This is why there is an output PAD on the JDV. This allows hot signals to be padded down so that they do not overload the input to mixers or mic level isolation transformers.

Q: Why don't you put the power supply inside the JDV?
A: Noise. Due to the JDV's abnormally high input impedance, the internal working level of the JDV is extremely low. This means that we must do everything we can to ensure unwanted noise stays out of the JDV circuitry. Power supplies tend to be a major contributor to noise. Keeping the noise outside is a good thing!

Q: What are the differences between the old Radial JDV and the new JDV Mk3?
A: The original JDV and the new JDV share the same audio circuit topology and philosophy. Both use the same Class-A feed forward designs. The old JDV used a rechargeable battery as a primary supply while the new design does not. We found that although the original JDV worked well, many users were confused about charging the battery and unless you read the manual, you could get some pretty awful distortion or worse yet, you would think the unit was defective.

The Radial JDV Mk3 is the third generation JDV and in developing this box, we set goals in place that included making the unit more user friendly, lowering the self-noise and expanding the dynamic range. All of the good things that were in the original have been maintained or wherever possible improved upon.

Obviously the new JDV has many more features. But that is not all: The new JDV has gone from using SMT (surface mount technology) to the higher capacity and precision of discreet components. In order to expand the headroom, we developed a totally new power supply with a floating ground scheme for less noise, and we got rid of the rechargeable batteries!

Q: Why did you not put a knob on the Drag control?
A: Originally, the Drag control was supposed to be recessed so that once set, the control would not be touched. However we found that it was so darn musical that people would be adjusting it all the time. Because the JDV will probably live on the floor most of the time, we felt that a knob would stick out and get kicked and broken. So no knob. Kinda' looks weird at first, but you'll get used to it.

Q: Why is the speaker pad switch recessed and difficult to get to?
A: The speaker pad switch has the most potential to cause damage to the JDV if used incorrectly. Connecting a speaker output directly to the JDV without the load the speaker pad provides will likely blow the JDV’s input circuitry. By recessing this switch, we reduce the chance that users will use it in error or without thinking of the consequences.

Q: How does the radial JDV Mk3 compare to the Avalon U5?
A: The Avalon is a good box. We tested it, took pictures, took it apart and then put it back together. We consider the folks at Avalon as good competitors. They make a credible product and their equipment is professional and sounds that way. Is the JDV better than the Avalon U5? No, we cannot in all honesty say that the JDV is better. We can tell you that our tests showed the JDV is probably more accurate but at this level, we are splitting hairs.

Here's our perception: People buy Radial direct boxes for two primary reasons.

Reason #1, Sound: ...or as we say, "the Radial un-sound™". Our boxes are extremely accurate and we do everything we can to ensure the integrity of the instrument is maintained without any added artifact or coloration whatsoever. We believe that our task is to deliver the sound pure and simple. The Avalon is equipped with a whole bunch of pre-set curves that allow the user to pick the sound he likes. The JDV is probably more natural while the U5 also has its place.

Reason #2 Construction:
The JDV is not as pretty as the Avalon. We recently challenged an Avalon user to drop his DI from 4 feet on the ground after we did this to the JDV. He declined. The Avalon is designed to be in the protective care of an engineer. The JDV will get kicked, jumped on, stacked and thrown around. I guess we're from the other side of the tracks where we expect our box to be subjected to real world abuse. This ain't no pretty boy!

Q: I am not getting much level. What could be wrong?
A: Check the recessed speaker pad switch. If this is pushed in, the input level will be way down. This is usually the offender because it is hard to see. Also, check the output pad to make sure it is not depressed.

Q: The sound seems a little muffled in the high-end?
A: If the Vary-Z is engaged and the Drag control is completely counter-clockwise, the sound can be muffled as you are dropping the input impedance well below normal. Also check to make sure the lo-pass filter is not on.

Q: Can I use the Tuner out to drive another amp of effect device?
A: Yes but this quality will be more on the lines of regular direct boxes. The tuner out is guitar level and is perfectly fine for effects and having fun. Of course its primary function is to keep you tuned without allowing the tuner circuit to get in the way of the sound.

Q: Why are direct boxes used in front of the bass rig when the 'bass sound' is the combination bass and amplifier and effects?
A: The reason for this is simple, yet the application is open for debate.
Here's the deal...

On stage, a bass player or guitarist should be setting his sound so that he is comfortable. The volume, the tone, angle of projection should be made so that the stage environment is as conducive to a great performance as possible. In the venue, the PA system is used to provide great sound for the audience. For example, more mid range on stage for the bass player may or may not fit well with the PA system mix. As such the engineer generally prefers to have as clean of a signal as possible from the bass. This avoids added distortion caused by introducing multiple layers of EQ or gain or effects such as compression in the signal path.

Today, you will often see the bass going direct while a microphone is also placed in front of the bass amp to get the post amplifier sound. The engineer will generally mix these together or sometimes switch sources depending on the song and the desired effect.

Ultimately, this is a creative decision. To help make this decision easier, the Radial JDV Mk3 is equipped with a standard DI (instrument level) set-up and a parallel speaker set-up to take the post amplifier sound. With a JDV, you get it all!