Radial J48 Active DI
Radial·Model J48·radial-j48
Photos
Manufacturer product photography — the drawn faceplate above stays true to panel layout; these show the hardware itself.
About the Radial J48
The Radial J48 is a phantomThe +48 V a console sends up the mic cable to power condenser mics and active DI boxes — invisible to gear that doesn’t need it.-powered active DIDirect Injection box — converts an instrument’s unbalanced signal to a balanced mic-level XLR so it can run long cables without noise. that excels with piezo pickups and other high-impedanceOpposition to signal flow, in ohms. Low-impedance IEMs are easier to drive loud; mismatches shift level and tone. sources that passive DIs struggle with. The built-in pad and polarity reverse give you troubleshooting options right at the source, which can save time during soundcheck. Powered entirely by 48V phantom from your mixer, it requires no batteries, making it maintenance-free for touring use.
The Radial J48 is a phantomThe +48 V a console sends up the mic cable to power condenser mics and active DI boxes — invisible to gear that doesn’t need it.-powered active DIDirect Injection box — converts an instrument’s unbalanced signal to a balanced mic-level XLR so it can run long cables without noise. box built for sources that passive DIs handle poorly — piezo acoustic pickups, keyboards with high-impedanceOpposition to signal flow, in ohms. Low-impedance IEMs are easier to drive loud; mismatches shift level and tone. outputs, and anything that sounds thin or harsh through a standard passive box. It lives at the instrument end of the signal chain, converting an unbalancedA single signal wire plus ground (guitar cables, RCA) — collects noise with length, so keep the runs short. instrument-levelThe in-between signal from a passive guitar or bass pickup — hotter than a mic, quieter than line, and high-impedance. Hence DI boxes. signal to a balancedCarries the signal on two wires and cancels whatever noise both pick up — why mic cables can run hundreds of feet hum-free., low-impedance mic-levelThe tiny signal straight out of a microphone — roughly a thousandth of line level. It needs a preamp before anything else touches it. XLRThe standard 3-pin locking connector for mics and balanced line signals — pin 1 is the shield, pins 2 and 3 carry the balanced pair. feed that can run long cable distances to your stage boxThe I/O endpoint on stage: mics plug in there and one digital line (AES50, Dante) carries everything to the console. The snake, digitized. or rack without picking up noise. The thru output lets you split to a local amp or tuner without interrupting the signal to front-of-houseFront Of House — the main mix the audience hears, and the console position out in the room where it gets mixed. or monitors.
Phantom powerThe +48 V a console sends up the mic cable to power condenser mics and active DI boxes — invisible to gear that doesn’t need it. is the key operational detail here. The J48 draws its operating voltage entirely from the 48V phantom your console or stage boxThe I/O endpoint on stage: mics plug in there and one digital line (AES50, Dante) carries everything to the console. The snake, digitized. already supplies, which means no batteries to swap mid-tour and no wall-wart to lose. The onboard pad gives you headroomThe margin between your normal level and where things clip — headroom is what absorbs the snare hit you didn’t see coming. headroom for hot keyboard outputs, and the polarity reverse is a practical tool during soundcheck when you're chasing phase issues between a DIDirect Injection box — converts an instrument’s unbalanced signal to a balanced mic-level XLR so it can run long cables without noise. and a mic on the same source — you can flip it at the box rather than diving into a console menu. At 0.5 kg it adds almost nothing to a gig bag.
If your rig regularly handles acoustic guitars with piezo pickups, keys, or synthesizers, the J48 is a reliable, maintenance-free choice that will outlast cheaper alternatives. Where it's not the right call: fully passive rigs where no phantomThe +48 V a console sends up the mic cable to power condenser mics and active DI boxes — invisible to gear that doesn’t need it. is available, or situations where you need stereo capture from a single unit and don't want to run two boxes. Engineers who prefer battery-backed active DIsDirect Injection box — converts an instrument’s unbalanced signal to a balanced mic-level XLR so it can run long cables without noise. for redundancyA second copy of anything critical — supply, computer, network path — already running so one failure can’t stop the show. against phantom supply failures should look elsewhere — the J48 has no backup power path. For the majority of live touring applications with phantom-capable systems, it's a proven workhorse.
In the rack
- Confirm phantomThe +48 V a console sends up the mic cable to power condenser mics and active DI boxes — invisible to gear that doesn’t need it. is enabled on the specific input channel before soundcheck — a silent J48 almost always means phantom is off or the XLRThe standard 3-pin locking connector for mics and balanced line signals — pin 1 is the shield, pins 2 and 3 carry the balanced pair. cable has a broken pin 2 or 3.
- Use the polarity reverse during line checkThe quick pre-show pass confirming every input reaches the console, one line at a time. Not a soundcheck — just does it work. when a DIDirect Injection box — converts an instrument’s unbalanced signal to a balanced mic-level XLR so it can run long cables without noise.'d acoustic guitar is combined with a mic on the body: flip it and pick the position where the low-mids fill in rather than cancel.
- If you're running the thru output to a stage amp, make sure that amp's input is unbalancedA single signal wire plus ground (guitar cables, RCA) — collects noise with length, so keep the runs short. TRSTip-Ring-Sleeve — a 1/4″ jack with three contacts carrying a balanced signal or a stereo pair. A guitar plug with one extra ring. or use an appropriate adapter — the thru is not a balancedCarries the signal on two wires and cancels whatever noise both pick up — why mic cables can run hundreds of feet hum-free. output.
- Label the unit with the artist or instrument name using gaff tape on the top panel; when you have multiple J48s on a busy stage plot, source identification at the box saves real time during changeovers.
PhantomThe +48 V a console sends up the mic cable to power condenser mics and active DI boxes — invisible to gear that doesn’t need it.-powered active DIDirect Injection box — converts an instrument’s unbalanced signal to a balanced mic-level XLR so it can run long cables without noise. with pad and polarity reverse.
I/O Ports (3)
| Port | Connector | Direction | Signal | Channels |
|---|---|---|---|---|
| Input (TRS) | TRS QUARTER | input | analog audio | — |
| Thru (TRS) | TRS QUARTER | output | analog audio | — |
| Output (XLR) | XLR MALE | output | analog audio | — |
Deciding between two?
Rack space, watts, weight and every connector, side by side.
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