ART ZDirect Passive DI Box

The ART ZDirect is a compact passive DI box that converts unbalanced instrument, line and speaker-level signals into a balanced, low-impedance XLR output, made for live sound engineers, gigging keyboard and bass players, DJs and home studios that need a reliable direct box without batteries or phantom power. It’s a simple, affordable way to get clean signals to a mixer over long cable runs.

What a DI box does

Instruments like keyboards, bass guitars and drum machines put out an unbalanced signal on a 1/4″ jack. Run that signal 20 metres to a stage box and it picks up hum and interference, and loses detail along the way. A DI box converts it into a balanced, low-impedance signal on an XLR, the same kind of signal a microphone sends, so it can travel long distances quietly and plug straight into a mixer’s mic input.

The ZDirect does this with an isolation transformer, which also separates the grounds of the two pieces of equipment. That isolation is what makes passive DIs so effective against ground hum.

Passive design: nothing to power

Because it’s passive, the ZDirect needs no batteries and no phantom power. Plug it in and it works, with no batteries to go flat halfway through a set and no need for a mixer channel with 48V. That makes it a dependable choice for stage boxes, installations and quick changeovers.

Pad, ground lift, filter and phase: when to use each switch

• Input pad (0, -20, -40 dB): use 0 dB for low-output sources, -20 dB for hot keyboards and line-level gear, and -40 dB for very hot signals such as a speaker output. If the mixer channel clips even with gain at minimum, move to the next pad.
• Ground lift: fully isolates the input from the chassis and output. Use it only when you hear hum from a ground loop. Leave it off otherwise.
• Low-pass filter: rolls off above 30 kHz (-3 dB point) to reduce radio frequency interference and digital noise from computers. Handy when DI’ing a laptop.
• Phase invert: flips the polarity at the output. Use it when you blend the DI with a mic on the same source, such as a bass amp, and the combined sound gets thin.

Thru jack for your amp

The input Thru jack passes your signal on unchanged, so a bass player can feed the front-of-house desk through the XLR and still use their on-stage amp. Run the instrument into the ZDirect input, and a cable from the Thru jack to the amp.

Audio performance

ART specifies a frequency response of 10 Hz to 50 kHz (±0.5 dB at +4 dBu), well beyond the audible range at both ends. Distortion is low, at 0.01% THD typical at 1 kHz and +18 dBu. The input is a high-impedance 50 kΩ, and the balanced output is 600 Ω.

Who is the ART ZDirect for?

• Keyboard players and synth users sending stereo or mono outputs to a PA. You’ll need one ZDirect per channel.
• Bass players with active basses, who want a clean DI to the desk while using their amp via the Thru jack.
• DJs and laptop performers who need to get unbalanced outputs to a desk without noise.
• Venues, churches and schools that want a stack of reliable, low-cost DI boxes for the live sound kit.
• Home studios connecting unbalanced gear to the mic inputs of an audio interface.

It’s less suited to passive guitar pickups. Its 50 kΩ input is lower than the very high impedance those pickups prefer, which can soften the top end. For a passive electric guitar or acoustic with a passive piezo, an active DI is usually the better match. Browse our full range of DI boxes to compare.

Passive vs active DI

• Passive DI (like the ZDirect): no power needed, handles hot signals well, and the transformer isolates grounds. Best for keyboards, drum machines, active basses and line-level sources.
• Active DI: needs phantom power or a battery, with a much higher input impedance. Best for passive pickups and low-output instruments.

Durability and care

The case is extruded, black anodised aluminium, so the box itself is tough. Reviewers point out that the switches are plastic and stick out, which makes them the most vulnerable part. Set your switches before the gig, and pack the ZDirect so nothing presses on them. Users on Gearank rate it highly for value, with a score of 88 out of 100 across more than 325 ratings, and the most common concern is those switches.

Key features

• Passive DI box with isolation transformer
• No batteries or phantom power required
• 1/4″ unbalanced input, 50 kΩ
• 1/4″ Thru jack
• Balanced XLR male output, 600 Ω
• Input pad: 0, -20, -40 dB
• Ground lift switch
• Switchable 30 kHz low-pass filter
• Phase invert switch
• 10 Hz to 50 kHz frequency response
• Black anodised aluminium case

Frequently asked questions

Does the ART ZDirect need batteries or phantom power?

No. It’s fully passive, so it works without batteries or phantom power. Leaving phantom power on at the desk won’t power it, and it doesn’t need it.

Can I use the ART ZDirect with a bass guitar?

Yes, especially an active bass. Use the Thru jack to feed your amp while the XLR goes to the mixer. A bass with passive pickups works too, but an active DI may keep a little more top end.

Can it take a speaker-level signal?

Yes. ART lists speaker-level sources among its uses. Use the -40 dB pad, and always start with the pad engaged before connecting a hot source.

How do I get rid of hum with a DI box?

Engage the ground lift switch. It isolates the input ground from the output, which breaks most ground loops between stage gear and the mixer.

Do I need two for a stereo keyboard?

Yes. The ZDirect is a single-channel DI, so a stereo source needs two units, one for each side.