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Radial Engineering ProDI Passive Direct Box

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Radial Engineering ProDI Passive Direct Box

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$110.44 to $144.00 Price Tier: Standard

4.5 (20)

3 Reviews

Find out who is using Radial Engineering ProDI

1 community setup

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8 wishlisted

54 saved

Page last updated Jul 03, 2026

Pricing and availability

We compare 600+ stores and found this item at 10 stores. Prices updated July 3, 2026.

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Reviews

Price

5.0 (75)

$134.99

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4.5 (24)

$134.99

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4.8 (585)

$134.99 New

$119.99 Used (Very Good)

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5.0 (22)

$110.44 65 available New

$79.99 14 available Used

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5.0 (22)

$134.99

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5.0 (1)

$134.99

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4.9 (8)

$134.99

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4.8 (204)

$145.00 $144.00 $1.00 · All time low

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£132.00

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5.0 (1)

$134.99

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Average Price: $128

Standard/Professional

$119

$300+

Price Tier

In the Direct Boxes category, Radial Engineering ProDI Passive Direct Box is priced in the Standard/Professional range. This is quality gear at a fair price point, suitable for beginners, hobbyists, and pros alike.

Budget

Standard

High-end

Price History

Based on price data from 7 merchants for "Radial Engineering ProDI Passive Direct Box". Prices shown reflect NEW condition. Tracking began Apr 2, 2026.

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Description

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Introducing the Radial Engineering ProDI Passive Direct Box, the essential companion for every musician and sound engineer. This high-performing, passive direct box delivers pure, noise-free signals for both live performances and recording sessions. It's the ultimate tool for preserving the natural tone of your instruments, ensuring zero coloration of your sound.

At the heart of the ProDI is a custom-made transformer, designed to Radial's exacting standards. This transformer provides galvanic isolation, eliminating hum and buzz from ground loops, and converting the high-impedance signal from an instrument to the low-impedance balanced signal crucial for long cable runs. The result is a clear, clean signal free of noise and interference.

The ProDI is more than just a high-performing box - it's a durable and reliable tool designed to withstand the rigors of live performance and touring. It's crafted with a 14-gauge steel chassis to protect the internal components. An outdoor-rated, baked enamel finish resists scratches and corrosion, ensuring that this box is made to last.

The ProDI keeps things simple while giving you maximum versatility. It works with a range of instruments, including bass, acoustic guitar, electric guitar, keyboards, drum machines, or any other instrument with a 1/4" output.

Key Features:

Custom-made transformer for optimal signal transfer
Galvanic isolation to eliminate ground loops
Linear frequency response from 20Hz to 18kHz for zero tone coloration
14-gauge steel chassis for high durability
-15dB pad switch for use with a wide range of instruments
Ground lift switch for eliminating stubborn ground loops
Single XLR output for simplicity and versatility
Suitable for use with a range of instruments with a 1/4" output

Owner's manual

Radial Engineering ProDI Passive Direct Box User Manual

Product specs

Type	Passive DI
Channels	1
Pads	-15dB
Ground Lift	Yes
Inputs	1 x 1/4"
Outputs	1 x XLR, 1 x 1/4" thru
Height	1.75"
Width	2.75"
Depth	4.25"
Weight	1.2 lbs.

FAQs

What is the primary function of the Radial Engineering ProDI Passive Direct Box?: The Radial Engineering ProDI is designed to convert high-impedance instrument signals into low-impedance signals suitable for mixing consoles, reducing noise and preserving audio quality during live performances or studio recordings.
Does the Radial ProDI require an external power source?: No, the Radial ProDI is a passive direct box, which means it operates without the need for an external power source or batteries.
Can the Radial ProDI handle high-output instruments without distortion?: Yes, the Radial ProDI is capable of handling high-output instruments, such as electric guitars and keyboards, without distortion, making it ideal for both stage and studio use.
What connectivity options does the Radial Engineering ProDI offer?: The Radial ProDI features a 1/4" input, a 1/4" thru output for connecting to an amplifier, and an XLR output for connecting to a mixing console or audio interface.
Does the Radial ProDI include a ground lift switch?: Yes, the Radial ProDI is equipped with a ground lift switch to help eliminate hum and noise caused by ground loops in audio systems.

Videos

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Reviews

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PROS

Clean, warm, pure sound quality
Extremely durable, "built like a tank"
No coloration, retains original tone
Very quiet with minimal noise
Great for both studio and live settings
Effective ground lift and -15db pad features
Transparent signal with passive pickups
Reliable for reamping and splitting signals
Easy to use with straightforward features
Good value for its performance

CONS

Not as "classy" sounding as higher-end models
One unit reported to have failed after extensive use
Exterior writing may come off with tape usage

Owner Insights

We analyzed real musician discussions from forums and Reddit to find what players love, question, and tweak about Radial Engineering ProDI Passive Direct Box.

Features and functionality

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A passive DI box like the Radial ProDI can be used in reverse for re-amping, requiring careful attenuation to match mic level.
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The ProDI includes a pad option, beneficial for high-output instruments, although some users prefer to apply a pad post-DI in studio settings.
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The Radial ProDI is praised for its minimal noise introduction compared to active DIs, attributed to its passive design and quality transformer.
Source

Mods and upgrades

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Using an h-pad, such as the Whirlwind IMP PAD Microphone Attenuator (-20db), can help adjust levels when using the DI box in reverse.
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Comparisons

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While a reversed DI box can work for re-amping, a dedicated reamp box like Radial's offers better signal quality and ease of use.
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DIY DIs with Cinemag transformers are reported to potentially offer superior sound quality to the Radial ProDI, though they may be less durable without the same protective features.
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Avenson Audio's Small DI is noted for its neutral tone and is considered a viable alternative to the Radial ProDI, especially when an isolated output is unnecessary.
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The Rupert Neve Designs prototype active DI with transformer is mentioned as a promising alternative for those seeking higher-end options, albeit at a higher price point.
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Use cases and applications

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Users have successfully set re-amp levels by comparing the clean output of their DAW with the sound of the guitar directly plugged into an amp.
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The ProDI is recommended for use with active pickups, as passive DIs complement active signals well, offering a clean and balanced output.
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User experience

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Some find that reamping does not replicate the tone of playing directly through an amp, suggesting it can be a useful alternative for specific performances.
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Users in urban environments may need to consider RF interference, but the Radial ProDI's shielding effectively mitigates this issue.
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Owners transitioning from Behringer to Radial ProDI note a significant improvement in sound quality, highlighting the perceived quality jump despite similar internal components.
Source

Build quality

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The Radial ProDI is noted for its robust construction, making it suitable for rough handling, although this might be less critical for studio-only use.
Source

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4.5 out of 5

Based on 3 Reviews and 20 Ratings

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1 star

liam_phillips

787

about 7 years ago

Great Transparent DI

I am new when it comes to audio production, so I got the first interface I heard of which is the Focusrite Scarlet 2i2. It's not bad, but even in its second generation, it has issues with the output of my passive pickups, even though they are not super high output. So I picked this up from a local guitar store and was blown away by how transparent it was. It fixed my attenuation issues and now allows me to adjust the gain on my interface without turning it close to 0. I have also heard great things about it for those who tour, and it is heavy. I am pretty sure I could drop this thing off a building and it would be fine. So I highly recommend it.