Tech Corner D.I. FAQs

In our recent Tech Corner Livestream, ‘A Good Day to D.I.’, we asked for your questions on all things D.I. and you didn’t disappoint. We had so many responses that we couldn’t get to them all on the stream, but we wanted to make sure we answered every one.

If you have a question about D.I.s that we haven’t covered here. You can contact our Tech Team and they’ll do their best to help.

What makes Radial devices different from other D.I.s on the market?

Build quality, the quality of the components used on the circuit board (including the transformers), our connection to our customers and artists that helps us create solutions that work for them.

What are the main differences between a J Series and a Pro Series D.I.?

J-Series boxes like the JDI/J48 are our top of the line direct boxes, and provide the best specifications we can offer in terms of distortion, flat frequency response, and phase shift. Passive J-Class boxes also feature premium Jensen transformers, widely regarded as the best in the industry. Our Pro Series direct boxes like the ProDI/Pro48 are a more economical line of products that still produces great results for use on stage or in the recording studio. Passive Pro Series boxes feature Eclipse transformers, which provide incredible specifications for their price point.

What’s so special about Jensen transformers?

Jensen transformers are widely regarded as the best in the audio industry, with extremely low distortion and noise profiles, ruler-flat frequency response, and low phase shift, meaning that they pass your signal through cleanly without noise or degradation to the sound.

Is the difference in transformers noticeable between the JDI and Pro D.I.?

While the Eclipse transformers in our Pro series direct boxes like the ProDI does an excellent job, Jensen transformers are known as the best in the industry for a reason. They offer exceptional signal handling, bandwidth and frequency response, and have very low noise and phase shift. While this may not be immediately audible on a busy live stage, it’s something that you will be able to tell the difference when doing A/B listening tests in the studio.

Why not just use an active D.I. on everything?

Passive direct boxes provide their own advantages and unique characteristics, which are mainly due to the audio transformer that is used in this type of design. While active direct boxes can distort when pushed with high output instruments and cause square-wave clipping, passive direct boxes will instead saturate the transformer inside and create harmonic distortion which is much more natural and pleasant to the ear. Passive D.I.s also don’t require power to operate, and they are preferred by guitar players and bassists who use instruments with active pickup systems or connect their D.I. at the end of a pedalboard.

Can you use a Radial Stereo D.I. as two Mono signals?

Yes absolutely. Each of our stereo D.I.s treats the left and right channels separately, so you can run one mono instrument through each side, or use it with a stereo instrument like a synth module.

​Are there any signal delays with active D.I.’s?

No, even active direct boxes are still analog audio products, meaning they have no digital conversion necessary and therefore no signal delay or latency.

On the J48 what is the effect of using the Thru on the sound source? Will it affect the balanced output in any way?

When using an instrument with passive pickups, there is a chance that connecting the Thru output to your amp will affect the impedance of the instrument, which can load down your pickups and result in a darker tone that will be audible through the amp as well as the balanced output. If you run into this issue, the easiest way to avoid it is to insert a buffered pedal into the signal path between the Thru output and the amp. Our PZ-DI also features a buffered Thru output which prevents the load on your pickups from changing no matter what you have connected to the Thru.

Why would the thruput of a D.I. alter the signal?

The Thru connection on a typical D.I. is wired in parallel with the instrument input, which means there will be a straight-wire connection from your instrument pickups to whatever you connect after the Thru output. Connecting the thru output to an amp will change the load on your pickups and can affect their tone, making them sound brighter or darker. Keep in mind this is only the case when connecting an instrument with passive pickups directly to the D.I. box, and it can be avoided by using a buffered pedal after the Thru connection or using a D.I. with a buffered Thru output such as the PZ-D.I..

What length of instrument/XLR cables can be used between a passive bass and the JDI without signal degradation?

With instrument cables, we generally recommend keeping them as short as possible to reduce the chance of picking additional noise or interference, ideally under 15ft. XLR cables that carry balanced audio signals like the outputs of a D.I. can be up to 300ft long or more without any appreciable loss of signal strength or quality.

On the Trim-Two, will using the parallel inputs, to send to monitors, load or change the sound of the source (in a bad way)?

Typically the Trim-two will be fed inputs from an active device, which won’t be loaded down or affected by connecting a pair of monitors to the other parallel input connectors. One thing that you will want to make sure is that you are using the same power source for your main input and the monitors, since there will be a chance of running into a ground loop between the two devices. The transformer in the Trim-two means that you don’t have to worry about ground loop noise between your inputs and any device connected to the XLR outputs.

Does Radial have a D.I. That can switch between mic level or Line level output ?

Yes! The HDI has both options available, so you can connect to a mic preamp as you would a typical direct box, or skip the mic preamp and connect straight into the line level inputs on your mixer or recording interface.

How does a D.I. remove hum and buzz?

D.I.s are equipped with ground lift switches that help reduce hum and buzz due to ground loops. A lift switch disconnects pin-1 ground at the XLR output of a direct box, which can break up a ground loop when it occurs between your source and destination devices. Passive direct boxes provide additional benefit by way of their internal transformers, which isolate the signal and provide even further protection against ground loop noise in the system.

What is the difference between transformer isolation and the “LIFT” switch on the D.I.?

A ground lift switch works by disconnecting the audio ground path on an XLR cable – it lifts the pin-1 ground connection which can help stop the ground loop from occurring. A transformer is a magnetic bridge that allows the audio signal to pass but creates a physical air gap in the connection, which isolates the equipment on either side from each other, providing a much more effective way of removing noise caused by ground loops.

What is Drag control?

Drag control is a feature found on many of our preamps and ABY boxes, it provides an adjustable input impedance to brighten or darken the sound of magnetic pickups.

Can the outputs of direct boxes be used with studio patchbays for routing purposes?

Yes, the output of a direct box is just like the output from a microphone, so it can be routed through studio patchbays with ease. As with any balanced signal you feed into your patchbay, make sure you use an adapter cable that preserves the balanced connection, for example an XLR > 1/4″ TRS or TT (tiny telephone) connector.

Can I use a D.I. in reverse as a reamp device?

Only passive D.I.s can be used in reverse, and even when you do so the results will not be ideal. For instance, a Reamp box will convert a line level signal to an instrument level, and also convert a low impedance balanced output to a high impedance unbalanced one. Running through a passive D.I. in reverse will take care of the impedance conversion, but it won’t reduce your signal levels to your pedals and amps. You could turn the track way down in your DAW to avoid overloading the inputs of your pedals and amps, but then you’d drop your signal much closer to the noise floor of your audio interface.

Why would you need a D.I. with a recording interface that has a instrument input?

The instrument inputs built into audio interfaces are often a feature that is ‘added-on’ to a design rather than something that is one of the main features of the product. In other words, some of the instrument inputs don’t sound that great. More attention is paid on audio interfaces to the quality of the mic preamps, and using a high quality D.I. will not only preserve the tone of your instrument, but it will also allow you to access the mic pre’s on your audio interface instead of using the instrument input, resulting in a better recording.

What would be the advantage of using the USB-Pro vs. a USB Interface?

The USB-Pro is a great alternative to an audio interface for audio playback on stage should you have stereo playback tracks or virtual soft-synths. It offers no hassle plug and play operation (no drivers required), high quality 24bit/96kHz audio playback, and an easy to adjust level control with a headphone output for testing and monitoring.

Is there any reason to use a D.I. when connecting a keyboard with balanced (TRS) outputs to a PA?

A passive D.I. box can still come in handy when connecting a keyboard with balanced outputs to the PA system for a couple of reasons. One is if you’re using an audio snake cable carrying other mic-level signals, as using a D.I. box will lower the keyboard outputs so that they are similar to the other signal levels in the cable and thus will reduce the chance of crosstalk. The other benefit is that the transformers inside a passive D.I. will isolate your powered keyboard from the PA system, which will greatly reduce the chance of encountering buzz and hum from ground loops.

What is the best D.I. to use from a pedal board?

We recommend using a passive direct box with a pedalboard. The transformers that do all the heavy lifting in a passive D.I. can take huge amounts of signal level before distortion, and even when they are pushed into the red they saturate and create pleasing even-order harmonic distortion.

What kind of D.I do you recommend to use with amp modellers?

We recommend pairing amp modelers with passive direct boxes, as the amp modelers themselves require power and are considered active audio sources. For modelers with stereo outputs, a passive stereo direct box like the JDI Stereo works great, as it can handle extremely hot signal levels without distortion and features Jensen transformers that provide isolation between your amp modeler and the PA to eliminate hum and buzz from ground loops.

Is there a DI to integrate with a Dante Network?

Yes there is, the DiNET DAN-RX is a direct box that can take instrument signals and integrate them into a Dante network.

How well does a D.I. work with modern Wireless systems – are there any impedance mis-matches or other issues?

The ProRMP Reamper is a secret weapon of live sound engineers and touring guitar techs, as it works very well for this application. It takes the line level balanced output from a wireless receiver and converts it back to a signal optimized for guitar pedals and amplifiers, melding the benefits of wireless systems with the sound of a straight-wire connection.

If a D.I. box could take care of ALL potential instrumental applications on stage, how big would it have to be?

The real question is could anyone build a stage big enough to hold it? A high quality passive direct box will handle a large percentage of possible applications on stage, so the answer might be about 3″x5″, the same size as the JDI.