Markertek - The Future of Broadcast Supply

Call 800-522-2025
M-F 8:30am - 7pm EST

Free Shipping Promo Box

FREE SHIPPING No Minimum Order!

SHOP MARKERTEK EVERYDAY for all of your needs. Free shipping on almost every order placed on our website.
Special order & oversized freight intensive items ship at an additional cost. Continental US orders only.
Ask about our new Economy International Shipping Options.

Secure LoginClose X

Returning Markertek Customers

New Markertek Customers

Why Create an Account?

Creating a Markertek account now will save you time on future orders. You'll have full access to your order history and a personalized shopping experience.

close - X

Radial J Plus-4 Stereo -10dB to Plus-4dB Line Driver
  • Radial J Plus-4 Stereo -10dB to Plus-4dB Line Driver
  • Radial J Plus-4 Stereo -10dB to Plus-4dB Line Driver
  • Radial J Plus-4 Stereo -10dB to Plus-4dB Line Driver
  • Radial J Plus-4 Stereo -10dB to Plus-4dB Line Driver
  • Radial J Plus-4 Stereo -10dB to Plus-4dB Line Driver
Questions? Ask a Markertek Expert:
800-522-2025 Email

Radial J Plus-4 Stereo -10dB to Plus-4dB Line Driver

Manufacturer: Radial Engineering

Item #: RAD-J4   •   MFG #: J4


List Price:$260.00
Our Price:$229.99

free ship
Availability: Usually ships in 3-10 business days
This item is currently out of stock and will ship the minute we receive it – normally 3-10 business days. Need it sooner? Call 800-522-2025 and we'll make it happen,or email Customer Service for expedited delivery options. Certain Non-Stock Items Valued over $50.00 may Ship FREE UPS GROUND in the Continental US. Multiple quantities of the same non-Stock Item Valued below $50.00 may be ordered to meet the $50 minimum order requirement to qualify for Free UPS Ground Freight. This offer does not apply to certain freight-intensive or hazardous items. Certain restrictions may apply.



    The Radial J+4 is a stereo interface designed to accept unbalanced low output level devices such as instruments, computers or CD players and boost the signal to a balanced +4dB level for easy manipulation in professional environments such as broadcast, recording studios and live touring.

    The design begins with 100% discrete components for optimal signal transfer. Careful attention has been paid to eliminate noise by combining the advantages of active signal buffering with transformer isolation. The J+4 delivers better than 95dB signal to noise while ensuring hum and buzz caused by ground loops along with spurious noise from clocking does not pollute the signal path. For ease of use, controls have been kept to a minimum. This includes a stereo level control, a high pass (low cut) filter and ground lift. The choice of input connectors include a stacked set of 1/4" jacks for DJ mixers or keyboards, RCAs for CD players and a mini 3.5mm for iPods.

    As with all Radial products, the Radial J+4 is built tough to handle the extreme rigors of professional touring. A unique 14-gauge steel I-beam inner frame ensures the sensitive PC board will not be subjected to outside stress which could potentially cause solder joints to fail. An innovative book-end outer shell creates protective zones around the controls, switches and connectors to further improve dependability while a full bottom no-slip pad provides both mechanical and electrical isolation.

    The Radial J+4 balanced line driver delivers exceptional sonic performance, plenty of headroom and ultra low noise making it the ideal companion for today's more demanding professional audio systems

    J+4 Applications

    Using the J+4 to boost a stereo signal
    Increasing the output from a CD player to a +4dB balanced signal is easy. Just plug into the RCA inputs, adjust the volume level and the J+4 does all the work. Transformer isolation eliminates ground loops for quiet performance every time. (see fig 4 above)

    Using the J+4 with your computer
    Today, computers and laptops are being used in all types of audio-visual systems. The J+4 makes it easy to interface with a built-in 3.5mm (1/8") TRS jack. Plug in and the J+4 will boost and balance the signal and deliver a professional line level signal. (see fig 5 above)

    Using the J+4 with a keyboard
    Many keyboards and synthesizers do not have enough output to effectively drive the line level input on a mixer. This is particularly troublesome on older keyboards such as a Rhodes piano. The J+4 makes it easy with built-in 1/4" inputs and balanced XLR outs.

    • Features

      • Stereo -10dB to +4dB interface
      • Transformer isolated to eliminate noise
      • Greater than 100dB of dynamic range
      • Plug and play easy to use
      • Phone, RCA and 3.5mm unbalanced inputs and XLR outputs
    • Specifications

      • Audio circuit type: Active -10dB ~ +4dB line converter, transformer isolated
      • Number of channels: Stereo
      • Frequency response: 20Hz ~ 20KHz (± 2dB)
      • Dynamic range: 102dB
      • Maximum input: +17dBu @ 1kHz, 1% THD+N
      • Total harmonic distortion: 0.004% @ 1kHz, +10dBu output
      • Phase deviation: 0.5° @ 100Hz; 4° @ 20Hz
      • Input impedance: 10k Ohms, unbalanced
      • Output impedance: 1.6k Ohms, balanced
      • J+4 transformer: Radial custom transformer
      • High pass filter: -3dB @ 100Hz (12dB.Oct.)
      • Ground lift: Disconnects XLR pin-1 at isolated output
      • XLR configuration: AES standard (pin-2 hot)
      • Connectors: 1/4", RCA, 3.5mm inputs; XLR-F outputs
      • Construction: 14 gauge steel chassis & outer shell
      • Finish: Durable powder coat
      • Size: (W x H x D) 84 x 127 x 48mm (3.3" x 5.0" x 2")
      • Weight: 0.70 kg (1.55 lbs)
      • Shipping size: W x H x D: 102 x 76 x 165mm (4" x 3" x 6.5")
      • Shipping weight: .87 kg (1.92 lbs)
      • Power: +15VDC/400mA adapter Included
      • Conditions: For use in dry locations only between 5°C and 40°C
      • Warranty: Radial 3-year, transferable

    Add Accessories for your J4:



    Continue Shopping View Cart