0% Interest for 48 Months on Top Brands

Radial J48 1-channel Active 48v Direct Box

Active 48-volt Phantom-powered Direct Box
$249.99

Earn $13 back in Bonus Bucks OR pay $6/month with 48 month financing*

In Stock!

Notify me about deals

Ask An Expert

Our expertly trained Sales Engineers are ready to help!

What is a Sales Engineer?
Sweetwater Gear Exchange

Have one to sell?
Check out Sweetwater's Gear Exchange!
Learn More

Most Popular Accessories & Related Items

Radial J48 1-channel Active 48v Direct Box
In Stock!
$249.99
Back to navigation

This article was Written By

Our Product Research Team

Get to know them!

A Great-sounding Active Direct Box

Over the past quarter century, sound systems have evolved as have the instruments that are now used. The listener has also evolved. CD quality sound is no longer a luxury, but expected. Only now are we beginning to hear and appreciate the advantages of a good direct box. A good DI must provide a wide distortion-free frequency response and the dynamic range to handle today's powerful instruments.

Radial J48 at a Glance:
  • Active 48-Volt phantom powered direct box.
  • Minimal power draw with high rail voltage.
  • Will not choke when driven hard.
  • Low inter-modulation distortion.
  • Innovative merge function.
  • 80Hz highpass roll-off filter reduces mud and increases headroom.

The Radial J48 is an active direct box that has been specifically designed to work around the limited current that is available with 48-Volt phantom power, and do so while delivering the pure and natural sound of the instrument. A unique switch-mode supply steps up the internal rails to allow an input signal of up to 10V without any noticeable distortion.

Will Not Choke When Driven Hard

The single most important development goal of the Radial J48 was increasing the headroom without compromising sound quality. To this end, every possible effort was made to deploy the limited energy resources of phantom power to the audio signal path. To begin, phantom power is converted using a super-efficient digital switch-mode power supply that steps up the internal rail voltage to an impressive 10 volts. This allows one to hit the J48 with as much as 9-Volts without choking! To further increase available horsepower, all non-essential devices such a power-hungry LEDs are turned off when the J48 is in use. A typical LED requires almost as much current as does the complete audio circuit!

Lower Harmonic Distortion

Open up the Radial J48 and you will see huge, over-sized capacitors that provide ample current storage to assure clean, unobstructed power for the signal. With added headroom comes improved performance in all areas: Less than half the phase distortion of competing DIs, significantly lower harmonic distortion and single-digit inter-modulation distortion are all realized. Paying attention to these basic details has the net result of better sound.

Innovative Merge Function

But great sound is not the only innovation: The Radial J48 introduces several new functions that improve functionality and open the doors for greater creativity. The input panel features the usual 1/4" instrument input and thru-put connections. An innovative Merge function converts the thru-put into a second input to sum stereo sources to mono such as stereo keyboards or CD players when mixer input channels may be of short supply. A -15dB pad may also be inserted when confronted with abnormally high signals.

Reduced Hum and Increased Headroom

To reduce low-end rumble and run-away acoustic resonance, an 80Hz highpass roll-off filter is provided. As with any power system whether it is acoustic or electrical in nature, bass always contains significantly more 'RMS power' than high frequencies. This is why low-frequency drivers require anywhere from 10 to 20 times more power in PA system designs than high-frequency tweeters. By gently removing unnecessary lows, the J48's dynamic handling is increased by a full 3dB or twice the power handling. This innovative feature both reduces mud and increases headroom at the same time!

Like all Radial products, the J48 is built to handle the abuse on the road and features a unique welded I-beam construction for years of trouble free performance.

Radial J48 Features:
  • Welded I-beam construction makes it impossible to torque the PC board. This virtually eliminates cold solder joints - the No.1 cause of system failure in the field.
  • An innovative 'slide-in-place' XLR trace makes it possible to use I-Beam girder construction.
  • A digital switching power supply steps-up the internal rail voltage to 9-Volts. The J48 will not choke like other DI's when hit with large transients.
  • A military-grade PC board is employed for maximum wear and tear in abusive environments. Welded steel standoffs ensure the PC board will not shift.
  • A -15dB pad allows super hot inputs such as that from a CD player to be connected and balanced for long runs.
  • Momentary 48V Check LED will flash once when the 80Hz filter is depressed to tell you phantom power is present.
  • The Merge function turns the input & thru into 'left & right' inputs to mono mix at the XLR output. This handy function saves valuable inputs on the mixer!
  • The input is connected to the instrument.
  • The thru-put is connected to the instrument amplifier. The J48 has a high input impedance to reduce loading.
  • Our book-end design creates a protective zone around the switches & connectors for best protection!
  • A heavy-duty baked enamel finish for excellent durability and great looks for years! 100% 14-gauge steel construction.
  • The 600 Ohm balanced XLR out is mic level to properly match concert splitters - will drive 1000 feet without appreciable noise.
  • A polarity reverse switch flips the polarity from the AES standard Pin-2 to Pin-3 on the XLR and is used when combining sounds that may be out of phase.
  • An 80Hz low-cut (highpass) filter gently reduces excessive bass for more headroom and clarity. Eliminates run-away resonant feedback from acoustics!
  • The ground-lift disconnects the ground path to the transformer at the XLR output. This is used when a ground path is made at the input side such as with a keyboard.
  • A no-slip full bottom pad reduces mechanical vibration, improves electrical isolation and keeps the J48 from moving around on busy stages!
The Radial J48 is a great sounding active direct box!

Warranty Info

Sweetwater's FREE 2-Year Total Confidence Coverage Warranty

Extra peace of mind at no extra cost.

  • Save money with FREE parts and labor
  • Get back to making music with the industry's fastest turnaround time
  • Fix it the first time with our award-winning, factory-certified Service Department
Learn More about Total Confidence Coverage

Free 2-year Warranty

Sweetwater's 2-year Total Confidence Coverage™ Warranty gives you extra peace of mind at no extra cost.

Learn More about Total Confidence Coverage
Tools Icon

Save money with free parts & labor!

Fast Icon

Get back to making music with the industry's fastest turnaround time.

Award Icon

Fix it the first time with our award-winning, factory-certified Service Department.

Back to navigation

Tech Specs

  • Type: Active DI
  • Channels: 1
  • Pads: -15dB
  • Polarity Switch: Yes
  • Ground Lift: Yes
  • Inputs: 1 x 1/4"
  • Outputs: 1 x XLR, 1 x 1/4" thru
  • Power Source: 48V Phantom Power
  • Height: 2"
  • Depth: 5"
  • Width: 3.3"
  • Weight: 1.55 lbs.
  • Manufacturer Part Number: R800 3001

What Makes Our Sales Engineers Great?

Sweetwater Sales Engineers are a world-class team of experts dedicated to you. Hand selected from across the globe, each brings a wealth of experience and expertise in the world of music gear to provide you with unparalleled service completely free of charge. Friendly relationships, real trust, and the right gear are only a call or a click away!

Back to navigation

Customer Reviews

Write your review
Rated 5/5

A must-have DI

First of all, when I got into analog summing in the home studio, I had no idea what I was doing. Kind of agitates me that I spent a few thousand dollars on analog equipment and got no instruction on how to connect it properly. I run tracks out of my interface, into analog gear and back into the interface. I had no idea I needed a DI to convert the line-level coming out of the interface into mic-level to run into my 500 Series preamps. I was using a TRS to XLR cable, which worked for a wile, till one of the interface outputs stopped working.

Overall, this little box sounds clean and professional. Worth every dollar. The only issue I found is that het phantom power LED doesn't turn on but the phantom power seems to work ok.
Music background: Always learning
Rated 5/5

Simple and user friendly

Versatile and easy to use. Ground lift for troublesome dirty power supplies provides clean pass through tones and elevates hum issues. Compact design allows for easy grab and go, just put it in a gig bag or guitar case.
-15db Pad and low cut buttons are great for functionality when using a variety of microphones. Overall, I should've had this direct box years ago. Best on the market
Music background: Bassist, engineer, and producer
Rated 5/5

Great DI for passive instruments

I purchased both the J48 mono for passive basses and the JDI mono for active basses. Both are great DI boxes for the studio. My clients are pleased with the sound of both DI boxes. I plan on picking up a PZ-DI for piezo pickups, a stereo JDI for keyboards and a 4 space J-rak to store all my new radial boxes in the rack.
Music background: Audio Engineer/Producer
Rated 5/5

Titles? We don't need no stinking titles.

Solid DI box. I am mainly writing this review because before I bought it, I was worried about the whole active vs. passive debate. Online, everybody says an active instrument should have a passive DI and vice versa. I couldn't find any reviews that really went over using active instruments through this box.

I have one passive bass but all the rest of my instruments are active. Most are 9 volt but two of them are 18 volt basses. I wanted something that would handle everything. Radial says this thing can handle 10 watts without distortion. So anybody with a typical 9 volt instrument should be fine. My main concern was the two 18 volt basses.

I can report that this sucker can handle the 18 volt basses just fine. At least in my case, with my instruments. Your mileage may vary.
Rated 5/5

What a Difference You've Made in My Life

What a huge upgrade in audio quality.
Very well built.

Hear from a Sales Engineer

What Do Our In-house Gear Experts Think?

Mark Magdich

The J48 Active Direct Box is absolutely amazing. I use it during a full-blown acoustic set with a 12-string. It's rich, has a lot of great output, and built like a tank (for all of you out there that know the kind of beating your gear takes when you are an active musician). Most of all, you can drive it to an extreme! Excellent choice and investment!

Dave Brow

This is THE DI to have! Excellent on bass, keyboards, and guitar. Get two, one for each ear!
Close Close $8,000 PA System Giveaway -- input your email address below to enter or click here to learn more.

See giveaway details & rules or check out our past winners!

Success!

Your email, test has been entered to win this giveaway. Good Luck!