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Radial ProDI Passive Direct Or DI Box With Custom Wound Transformer

The ProDi can handle huge transients without distortion


$199.00 $239.00

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Radial ProDI Passive Direct Or DI Box With Custom Wound Transformer

  • Compact passive direct box for stage and studio
  • Able to handle huge transients without distortion
  • Transformer isolation eliminates noisy ground loops
  • Plug and play easy to use feature set - on stage or in the studio

The Radial ProDI is a passive direct box that combines exceptional audio performance with solid dependable construction, making it the ideal general duty direct box for stage and studio.

The heart of the ProDI is a custom wound Radial transformer. It features an exceptionally high 140kΩ input impedance to reduce loading while enabling the ProDI to handle extreme signal levels at all frequencies without distortion. This is further improved upon with an internal MuMETAL® shield to protect against electromagnetic fields that can cause unshielded transformers to distort.

This compact direct box begins with 14-gauge steel I-beam skeleton for added rigidity and Radial's unique book-end design that creates a protective zone around switches and connectors. Glass filled nylon connectors and high cycle switches combine with the mil-spec PCB and internal RF filtering to provide durability and noise-free performance. A full bottom no-slip pad provides both mechanical isolation and electrical insulation to further protect against the rigors of professional touring.

The ProDI is ideally suited for instruments such as bass guitar, active acoustics, keyboards and just about anything else! When you consider all of the features and the affordable price tag, it is no wonder the Radial ProDI has become one of the most popular direct boxes ever made.

The Radial ProDI… Spectacular performance at a price that anyone can afford!

ProDI with electric bass

The ProDI works great for high output devices like active bass guitars. It is able to handle the huge signal levels from active pickups without distortion and the transformer isolation pevents ground loop hum. The ProDI sends the pure sound of the bass to the PA and to the player's amp.

ProDI with acoustic guitar

Acoustic guitars can sometimes have sharp sounding active preamps. The ProDI naturally smoothes out the transients for a warmer tone. And because the ProDI is able to handle loud signals from active pickups, it will not distort. This makes it a great direct box for acoustic guitars.

ProDI with a Keyboard

Today's digital keyboards are not only very dynamic, they also have a tremendous range from low to high notes. The ProDI is able to withstand excessive signal levels at all frequencies without introducing distortion or phase shift so all your patches sound great.


The Radial ProDI is a professional grade passive direct box that employs the same high quality audio transformer used in the ProD2, ProAV1, ProAV2 and ProD8. Designed to be 'plug and play' easy to use, the ProDI supports a standard feature set that is ideally suited for live touring, yet equally effective for the studio. It is able to withstand exceptional signal levels while delivering a clean, natural tone with minimal distortion of all types.


Radial ProDI Block Diagram
Click to view larger image.
Specifications RADIAL ProDI
Audio circuit type:  Passive, transformer based
Number of channels: Single channel (mono)
Frequency response:  20Hz ~ 18.5KHz (± 0.2dB)  
Dynamic range:  128dB 
Maximum input:  +18dB @ 20Hz 
Total harmonic distortion:  0.01% from 20Hz~20kHz @-10dB
Phase deviation:  1° @ 100Hz; 8° @ 20Hz 
Input impedance:  140k Ohms, unbalanced 
Output impedance:  150 Ohms, balanced 
Transformer: Eclipse ET-DB2, 12:1 ratio
Shield: Faraday, MuMETAL® can
Input pad:  -15dB  
Ground lift:  Disconnects pin-1 at XLR output 
XLR configuration:  AES standard (pin-2 hot) 
Connectors: 1/4" in & thru, XLR-M out
Construction:  14 gauge steel chassis & outer shell
Finish: Durable powder coat
Size:  (W x H x D) 70 x 108 x 44mm (2.75” x 4.25” x 1.75")
Weight:  .54kg (1.2lbs) 
Shipping size: W x H x D: 102 x 76 x 165mm (4.00" x  3.00"  x 6.50")
Shipping weight: 0.61 kg (1.35 lbs)
Power:  Passive, no power required 
Conditions: For use in dry locations only between 5°C and 40°C
Warranty:  Radial 3-year, transferable
Specifications are subject to change without notice.
Radial ProDI Frequency Response Graph
Radial ProDI Phase Response Graph
Radial ProDI FFT Graph
Radial ProDI THD+N vs. Frequency
Click to view larger graphs


Radial ProDI Features


Please Note: This item may be on display at the Mooloolaba Music Shop and may have been available for demonstration to in store patrons. We take careful and meticulous care, boxing and cleaning of your product before the shipping or selling of an item. If you do want photos beofre making a purchase please call our shop where one of our staff can assist in sending more detailed images.

Mooloolaba Music reserves the right to cancel, at any time before delivery and for whatever reason, an Order that it has previously accepted. Mooloolaba Music may do this for example, but without limitation, where:

a) Mooloolaba Music's suppliers are unable to supply Goods that they have previously promised to supply
(b) an event beyond Mooloolaba Music's control, such as storm, fire, flood, earthquake, terrorism, power failure, war, strike or failure of computer systems, means that Mooloolaba Music is unable to supply the Goods within a reasonable time
(c) Goods ordered were subject to an error on the Website, for example, in relation to a description, price or image, which was not discovered prior to the Order being accepted;
(d) The products shown in the images above product may differ to the purchased product. Changes could include, different stands, treatments, slight variations in colour, In-built batteries and charging ports. Please contact our team for further clarification.

We ask that you research parts carefully before buying.
Purchase of any non-licenced part as a replacement spare part is at your own risk.
Some branded replacement parts also require professional installation to fit correctly.
If in doubt we will be happy to advise further and confirm suitability before purchase.

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