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Radial PRO-D8 Eight Channel Rack Mount DI, 1u

Product Code RAPRO-D8
Manufacturer Radial

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The Radial ProD8 is a high performance 8-channel passive direct box optimized for keyboard rigs in professional touring. The design begins with fully redundant dual ¼" inputs on all channels. These are summed together to enable the system tech to patch in a backup keyboard and have it on standby should a device go down during a show. This also enables up to 16 keyboards or 8 stereo sets to be connected should the need arise. A (shared) ¼" TRS effects insert jack on each channel allows two keyboards to share the same effect while adding greater routing options while ¼" thru-put delivers a direct feed to the artist's playback system.

The engine inside is a custom wound Eclipse ET-DB2 transformer that performs both the impedance matching and balancing. Linear from 20Hz to 20kHz, it is able to withstand the extreme dynamics common with today's digital keyboards. Unlike active circuits that overload and square wave when the rail voltage is exceeded, transformers saturate. This means that as the signal increases, the ProD8 naturally rounds out the tone producing a warm Bessel curve reminiscent of the very best vintage audio gear. The other significant advantage to this passive design is 100% galvanic isolation between the source and destination. This eliminates hum and buzz caused by ground loops, resulting in a quieter stage.

The output panel features isolated XLRs each equipped with ground lift and 180º polarity reverse. Internal switches may be routed to accommodate various schemes such as star grounding. To enhance setup options, the Radial ProD8 is equipped with reversible rack ears. This handy feature allows the system tech to position the inputs on the front of the rack when interfacing with external keyboards or have them inside if the setup is predominantly equipped with rack modules.

The Radial ProD8 delivers unsurpassed audio quality, is able to withstand extreme dynamics, eliminates noise and presents a wide range of setup options. It is no wonder that it has become the world's most popular rack DI for concert touring.

Key Features

  • High density 8-channel rackmount DI for keyboards
  • Withstands extreme dynamics from digital sources
  • Redundant inputs let you incorporate backup system
  • Reversible rack ears to optimize patching setup


Audio circuit type: Passive, transformer based
Number of channels: Eight channel
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
180° polarity reverse: Inverts absolute phase
Ground lift: Disconnects pin-1 at XLR output
XLR configuration: AES standard (pin-2 hot)
Connectors: 1/4" in & thru, TRS insert, XLR-M out


Construction: 14 gauge steel chassis & outer shell
Finish: Durable powder coat
Size: (W x H x D) 483 x 44.5 x 159mm ("19" x 1.75" x 6.25")
Weight: 3.26 kg (7.2lb)
Shipping Size: W x H x D: 260 x 114 x 568mm (10.25" x 4.50" x 22.37")
Shipping Weight: 3.76 kg (8.30 lb)
Power: Passive, no power required
Conditions: For use in dry locations only between 5°C and 40°C
Warranty: Radial 3-year, transferable

Equipment available to buy from this site is for professional use only. Please note in certain countries some products listed may not be available from A.C. Entertainment Technologies Ltd.

E&OE. Information is subject to change without notice. The rights and ownership of all trademarks are recognised.


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