ZED10FX, direct box for hum?

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1

I have a ZED10FX from 2012. I understand it has Hi-Z inputs for plugging a guitar directly in. However, when I do that, I get the hum that happens when you’re not touching the strings. As I understand, the solution to that issue is a direct box with a ground/lift switch. What should I look for when getting a direct box? We’re using mostly archtop guitars with humbucker pickups. AI suggests the Radial JDI passive. Thank you

2

I’m not sure DI box will solve your problem. Sounds like a grounding issue with your guitar itself to me. Someone in a guitar forum or subreddit would probably know for sure.

But to answer your question, it doesn’t matter as long as it has a ground-lift switch. The JDIs are relatively expensive, but they do sound great :man_shrugging:t2:

3

I highly doubt that.
Last time I read such a topic, it drifted away to an esoteric discussion about unbalanced jack cables for ground loop prevention.

You need to find out why there is humming. The hum-bucker pickups should prevent it.

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4

And one more addition:

As is often the case, I have a different opinion than AI and would not recommend a passive DI box for optimal connection of a purely passive guitar.

5

According to the AI:

For your archtop guitar with passive humbuckers, both are excellent choices, but they will yield different results:

  • Choose the Radial J48 if: You want a modern, clear, and detailed sound. The active circuitry will provide a strong, clean boost to your passive pickups, resulting in a well-defined signal with plenty of headroom . This can be ideal if you want every nuance of your playing to be captured accurately.

  • Choose the Radial JDI if: You prefer a classic, warm, and “musical” tone. The passive transformer is known for smoothing out the signal, often described as adding a pleasing, analog warmth . It’s incredibly reliable for live use since it needs no power.

Given that your goal is to eliminate hum, both models feature a ground lift switch, which is the primary tool for solving that specific issue . The JDI is often praised for its exceptional shielding against electromagnetic interference .

To put it simply: if you want a crisp, modern sound, go for the J48. If you want a warm, classic sound, the JDI is a legendary choice.

6

When I asked the AI about plugging directly into the Hi-Z input of the ZED vs the need for a direct box:

Your Allen & Heath ZED10FX mixer has a truly exceptional, high-quality Hi-Z input—far better than the simple “instrument jack” found on most mixers.

Let’s break down what that description means:

  • Extremely High Impedance (10 Mohms): This is perfect. It’s even higher than the standard 1 Mohm input on most DI boxes and guitar amps. This ensures that not a shred of your guitar’s high-end detail will be lost.

  • Class A FET Circuit: This is the key. Instead of just being a simple jack, it’s a dedicated preamp circuit designed to emulate the sound of a valve (tube) guitar amp. This is a premium feature.

  • Warm 2nd Harmonic Character: This is “musical” distortion—the pleasant, warm overdrive that makes tube amps sound so good. It means this input is designed to add a pleasing character to your sound if you drive it hard.

So, Do You Even Need a DI Box?

This is the big question now. For connecting your archtop guitar, you may not need an external DI box at all for basic connectivity and tone. The Hi-Z input on your mixer is specifically designed to do the job beautifully.

I was plugged direct into the hi-z input, and that’s when I was getting the bad hum. When I added the Samson MDA1, the hum got a little better, but it introduced a lot of hiss. So now my question is, if the Hi-Z of the ZED eliminates the need for the direct box, to address the hum, do you think the Morley Hum Eliminator would be all that I actually need?

7

Sorry I’m out here, can’t understand that b…t.

Stop thinking and let the AI do it for you, oh wait, you did it already.

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8

No, a hum eliminator will not help. Those device are to solve ground loops issues. Your issue is EMF/RFI related where the guitar is acting like an antenna and pickup up EMF or RFI and rectifying it into the audio band. When you touch the strings or metal parts grounded to the guitar itself, you’re shunting that noise. There may be a wiring issue with the guitar. Also, with high impedance guitar pickups, the guitar cord itself can have an impact on the noise pickup. Have you tried other guitar cables? Lastly, when using DIs, you don’t want to use a passive DI like the JDI unless there are active devices such as pedals between the guitar and mixer or an active pickup system. For passive pick systems, you want an active DI between the guitar and the board.

Also, if the problem only occurs in one venue or room in particular, the electrical environment may simply be too “hostile” to the point that the hum buckers and guitar cord can’t counteract it.

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9

We are using a reverb pedal before the mixer. Radial even suggests the passive JDI for archtop guitars. Just the fact that the lower grade Samson DI reduced the noise suggests to me that a higher quality DI might improve the situation further. I know it’s not the guitar wiring, or the pickup as it happens with other guitars too.

10

Originally you connected your guitar directly into the mixer and now you have a pedal in between?

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No, the pedal was always there, Dunlop MXR reverb pedal. The only thing that changed was the introduction of the Samson DI box.

12

Okay, but that’s obviously something completely different than connecting the guitar directly to a Hi-Z input on the mixer with a dedicated instrument cable, which is what you wrote first.
What happens when you do that?
Does it hum there too, and at a similar level?