J33™ Using & Applications

This short guide is written for those who are experienced with pro-audio and direct boxes. Complete details about the many features built into the J33 phono pre-amplifier and direct box including information about connecting it to your system can be found in the user guide. Click to view the complete J33 user guide (290kb).

The Radial J33 is a combination turntable preamp and direct box. This device has been developed to interface a conventional turntable with magnetic cartridge with professional balanced audio systems as well as consumer unbalanced hi-fi systems. With its straightforward design, the Radial J33 is very easy to use. It can be powered using 48V phantom or by the external power supply.

Making Connections

As with any electronic audio device, make sure all levels are turned down and/or power is off before making connections. This avoids power-on transients or capacitor discharge from harming speaker components. Always test at a low volume to make sure connections and cables are working properly.

 

Using the J33 with a professional mixing console or preamp


J33 powered by 48V phantom
  1. Connect the turntable to the J33 RCA PHONO inputs. Be sure to observe proper left, right stereo connections.
  2. Connect the turntable ground wire to the J33 ground lug. This is a screw-down connection you tighten with your fingers.
  3. Connect the left and right balanced outputs of the J33 to the inputs of two microphone preamps using the XLR connector.
  4. In this setup the J33 receives power from the mixing console or mic preamps through +48V phantom power. Turn on the phantom power on for both the left and right channels at the console or preamp.
  5. The power LED indicators on the J33 will illuminate when phantom power is present. Ensure that both LED's are illuminated.
  6. Cue up your vinyl LP and test the system at a low volume. If all is well you are ready to go!
 
 

Using the J33 with a consumer preamp or unbalanced device


J33 powered by the included external power supply
  1. Connect the turntable to the J33 RCA PHONO inputs. Again, be sure to observe proper left, right stereo connections.
  2. Connect the turntable ground wire to the J33 ground lug. This is a screw-down connection you tighten with your fingers.
  3. Connect the left and right RCA OUTPUT jacks to a hi-impedance, line-level or auxiliary audio input on your stereo receiver, DJ mixer or laptop computer.
  4. In this setup the J33 receives power from the included 15V DC power supply unit. Connect the power supply to the J33.
  5. The power LED indicators on the J33 will illuminate when the external power supply is connected. Ensure that both LED's are illuminated.
  6. Cue up your vinyl LP and test the system at a low volume. If all is well you are ready to go!

Note: The Radial J33 will automatically sense the power from either the 48V phantom or the external power supply. If both the phantom power and the supply is connected, the J33 will draw its power from the external power supply.

Important Note: When switching from 48V phantom power to the external DC supply, please wait 15 seconds to allow the RIAA amplifier to charge and stabilize.

TRS and 3.5mm Stereo Output Jacks

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In addition to the RCA phono jacks the J33 inclues a ¼ TRS and 3.5mm stereo outputs. You can use any or all the output connectors at once, enabling you to, for instance, connect your turntable to the J33, the -10dB RCA line-level outs to a DJ mixer and the balanced XLR outs to a PA system. Depending on how the equipment is connected to the AC mains, there can be a potential for ground loop hum when using both the balanced and unbalanced outputs at the same time. If a ground loop hum develops, a possible solution is to lift the ground at the PA mixer and use the J33's 15VDC external power supply.

Rumble Filter

The J33 is also equipped with a low-frequency rumble filter. This gently rolls off the bass to reduce the low frequency rumble and resonant feedback that can occur when spinning records in high volume environments such as on stage or in nightclubs. If your turntable picks up vibrations that create low frequency rumble or feedback try toggling the FILTER switch.