At publication time this was the Highest Rated Mono Active DI Box - a title it has had for the previous 3 years in addition to being the equal highest rated before that.

Started back in the '70s, the brand Neve and their preamps and consoles continue to hold prominent status when it comes to music equipment.

So it is not surprising that their DI Box would rank high in this list, thanks to its impressively high Gearank Rating score which includes many experts recommending it.

Interestingly, what makes this unit special is not necessarily its straightforward DI Box functionality, but its amplifier section which features the same Class-A discrete FET amplifier as found on popular Neve consoles.

Features

• 48V phantom powered active circuitry
• Ground Lift switches for both speaker and instruments
• 1/4" Input and Thru-put jacks, gold-plated XLR output
• Steel chassis
• Weight: 1.5lbs

Pros

Reviewers are consistent in saying that Neve RNDI "improved" their sound so much that it has become a critical tone element, rather than just being a mere bridge to the mixer. Reviewers report how this unit works well with bass, acoustic guitars, keyboards, amplifiers, and more. And many of them testify that it makes all these instruments sound warm and big, with little tweaking.

Cons

The simplicity of this DI Box wasn't enough for some looking for more control. It may also not be ideal if you're looking for something transparent, because the amplifier section warms up the sound. Interestingly, even those who wanted something "transparent" ended up loving the warmer and bigger sound that they got after plugging into the RNDI. Finally, you must invest a considerable amount of money for this straightforward DI Box, but based on the positive response it has been getting, it is well worth the price.

Overall

We highly recommend the Rupert Neve RNDI for bass, but it can also work well with any instrument. If you are looking to add more juice to your FOH sound then you should check this one out.

At publication time this was the Highest Rated Stereo Active DI Box - now for the third year in a row!

Expanding on the RNDI (also covered in this guide), The Rupert Neve Designs RNDI-S is the stereo version of the RNDI.

Features

• 48-Volt phantom powered direct box
• High rail voltage design to avoid clipping
• 80Hz highpass roll-off filter for reducing mud and increases headroom
• Input 1/4", Outputs XLR, 1/4" thru
• Weight: 1.55 lbs

Pros

For stereo DI boxes, stereo coherence is important especially during recording from stereo sources like effects, keyboards, and loops and samples. The better the phase coherence between channels, the better stereo tracks fit into the mix. Several pro engineers consistently write about how the circuitry adds certain dynamics that recording without one didn't bring to their sessions. One user even used 7 for his touring band just for the consistency and sound.

Cons

No reported negatives for the unit itself. Price has been an issue with the RNDI-S simply being out of reach for most project studios.

Overall

Despite being at the more expensive end of our list, many users praise the RNDI-S for its sonic enhancements, phase coherence, and build quality. If you're looking to upgrade your already stacked studio, get it; it might just be that last small improvement your workflow/signal chain needs.

At publication time this was the Equal Highest Rated Mono Passive DI Box along with the Radial JDI.

At just half the price of the JDI model, the Radial ProDI brings the company's famed sound quality and reliability to a more accessible price point.

Because of its reasonable price tag, venues that house multiple instruments like churches have been getting these in buckets.

And looking at its impressive Gearank Rating, the quality does not stray too far from more expensive units, some even comment that differences are practically unnoticeable in most musical applications.

Features

• Passive direct box design with isolation transformer
• Isolated and balanced XLR output connector to prevent chassis to ground noise
• Radial 14-gauge steel welded I-beam housing
• -15dB pad
• 1/4" input and 1/4" thru-put
• Ground lift switch
• Weight: 1.2 lbs

Pros

While it is reassuring that professionals like Terry Lawless (who plays keyboards for the band U2) endorse this unit, it still pays to heed the advice of regular users, and they have many good things to say about the Radial ProDI. Almost everyone is satisfied with its clear audio and solid construction, it also helps that it is compact and readily portable. From keyboards to laptops, and even instruments, the ProDI will get you sounding good with little hassle.

Cons

There was one who warned that the rubber footing will eventually fall off so that maybe something to look into and prevent. Other than that, there are not that many complaints, even some of those that ranked this DI Box lower reported that they are very happy with it.

Overall

If you are looking for an all-round DI box for your keyboards and other electronic instruments, that's relatively easy on the pocket, then check this one out.

At publication time this was the Highest Rated Stereo Passive DI Box - now for a third year in a row!

There's no question that Radial Engineering dominates the DI box market with their range of offerings for almost any situation.

The ProD2 is their transparent, 2-channel DI box solution for keyboards, program material, and other high output sound sources.

The box was designed to smooth out extreme transients while keeping most of the input intact. This prevents overloading your mixer or audio interface's preamp.

Features

• Full range passive direct box with Eclipse ET-DB2 transformers
• Very low harmonic and phase distortion
• 14-gauge steel welded I-beam construction
• -15dB pad
• Input 2 x 1/4", Outputs 2 x XLR, 2 x 1/4" thru
• Weight: 1.95 lbs

Pros

Users praise its transparent sound while smoothing out harsher transients and background noise. Where other DI boxes color the sound in obvious ways, the ProD2 is consistently praised by reviewers and users to maintain more true to the input while rounding any excess digital "harshness".

Cons

An isolated report of signal loss. The community figured that the jacks need to be cleaned or cables checked as this is a rare case.

Overall

Radial Engineering puts a winner in the lineup again with the ProD2. It ticks all the boxes of what a good stereo DI box should be while bringing out the best of your instruments.

The ProRMP is Radial's most affordable reamp box.

Being affordable doesn't mean they skimped out on quality and features.

Featuring a modified version of the JCR circuit and transformer, the ProRMP feeds your amp with a strong and harmonically rich signal for sweeter cleans and fatter overdrive tones.

Features

• Passive design re-amping box with custom transformer
• 14-Gauge steel welded I-beam construction
• On-board level control
• Input 1 x XLR , Outputs 1 x 1/4" TS
• Weight: 1.2 lbs.

Pros

Many happy users have noted that "it does what it says on the box" which is to enable you to feed a DI signal from your computer to an amp. The signal itself sounds close to how the recorded tone would sound from a guitar without too much fuss.

Cons

The level adjustment requires a flat head screwdriver to adjust. This made it inconvenient for a few users who need to make adjustments on the fly.

Overall

As the "little brother" of Radial's Reamp box line, you might expect some compromises with sound and build quality but the ProRMP delivers with a lot of convenience, reliability, and value.

Things to Consider when Buying a DI Box

So what is a DI Box for anyway?

The main job of a DI Box is to convert your instrument lead (1/4" TS) signal 'directly' into the microphone inputs (balanced 3-pin XLR) that a mixing console typically has. Unlike a simple headphone adapter (1/4" to 1/8") it doesn't just need to change the size or shape of the connectors, it has to convert the differences in impedance and voltage between the two sides of the connection. The details of how it does this are beyond the scope of this guide but if you want to delve further into the topic then look at this DI article on Wikipedia. The main thing to consider is that due to electrical designs this conversion process can influence the tone of your instrument (in a good or a bad way) and that's why getting the right DI Box is important.

Apart from just "getting the signal to the desk" a DI Box (also called Direct Box, Direct Input, or Direct Injection Box) can also have several other advantages. Firstly the balanced XLR connection is much better for running cables over long distances without picking up noise and interference. Guitar leads, for example, can lose some sound quality at around 20 feet (6m) so if you want to cover more distance than a balanced XLR cable from the Direct box is better. Secondly, many DI boxes (especially passive ones) isolate the input and the output circuit which can help prevent ground loop hums and other electrical noise from creeping into the sound system.

Passive vs Active

There are two types of DI boxes - Passive and Active. Passive DI boxes work with no external power source, while active direct boxes require either phantom power, a battery, or a separate power supply. Active DI boxes offer more functionality and improved sound quality, while Passive Direct Boxes offer straightforward functionality without having to worry about the power supply. The general rule is to use an Active DI Box for instruments with passive pickups and use a Passive DI Box for instruments with active pickups and electronics. If you're wondering whether your instrument is passive or active it's simple - if you have to supply power or put a battery in then it's active, otherwise, it's passive.

Input/Output Ports

The most basic form of a DI Box usually has one input and one output that goes straight to the mixer. As the price goes up, they offer more options that include a separate output for amp or monitoring, while some even have multiple input/output options for complex rigs and multiple instruments. You'll want to have a DI Box with the right amount and type of inputs for your needs. If you're using a single instrument like electric bass, or acoustic guitar then a compact straightforward DI Box would be more than enough.

Ground Lift

The more music equipment you manage, the more voltage differences there may be between them, and these differences are perceived by the mixer as hum and noise. Since Passive DI boxes are transformers, they provide automatic ground lift for instant noise and hum reduction, making them important in keeping stages and studios quiet and clean sounding. Active DI Boxes also provide this feature, with some of them having a ground lift switch that isolates the signal ground from the unit's chassis ground.

Size

As mentioned above, more features and connectivity options require space, which increases the size of the box. It is important to find one that has just the right connectivity and features packed inside a unit with a size that's comfortable for you to use or carry around.

Are Regular DI Boxes and Reamp DI Boxes Interchangeable?

Because of the different purposes with both devices, it is best to choose a box specific to your needs. DI boxes are for feeding signals into a recording interface or mixer while Reamping DI Boxes convert pre-recorded signals for going into amplifiers or effects processors - these require a different impedance level to mixing consoles.