Voltage is one thing, there is likely also a big impedance issue as well plugging an instrument level output into a line input.. And if it's a balanced line input on top of it, even more fun!

 

Mine is a cheap Chinese guitar its output is 3.2Vpp at least. But I have a Schecter Omen Extreme with me for tests with factory Schecter Diamond pickups, and I measured 3.4 for those. I couldn't measure a ture max, only an "at least" maximum, because I had no oscillator, I measured it in a different way. So it is possible that the true maximum is well over these. And I also had similar clipping problems with a PRS Custom, I guess that outputs at a value similar to these.

The problem of the iD clipping is legit anyway:
https://www.reddit.com/r/Guitar/comments/zeamc3/question_audient_id14_di_is_clipping_anyway_to_fix/

 

Millenium DI-E passive DI-Box - 14,90 € ---> www.thomann.de/de/millenium_die_dibox_passiv.htm
BSS Audio AR-133 Aktive DI-Box - 109 € ---> www.thomann.de/de/bss_ar133.htm

Audient iD4 MKII = D.I. Gain: -5 to 45 dB (including +10 dB Software Boost)

Audient iD4 = D.I. / Instrument Input
RANGE: 40 dB
LINEUP: 12 dBu = 0 dBFS
THD+N at 0 dBu: 0.1%
SNR: 100 dBu A-weighted
FREQUENCY RESPONSE – MIN. GAIN: ±0.5 dB 10 Hz to 20 kHz

Give your amp simulators the analog warmth and character they've been missing. The iD4 JFET instrument input is designed to emulate the input stage of a classic tube amplifier, providing your guitar or bass with the perfect sonic foundation from the very first note.

Source: https://audient.com/de/products/audio-interfaces/id4/overview/

 

What I don't understand: why not build an interface with normal inputs, then you don't need a Di box. My other interface is 15 years older than the iD4, and it never goes clipping. The input on that one is rock solid. One reason is that it shows the clipping, while the iD4 doesn't even show it. You can't verify the level is okay. The meter is still in green but it is clipping.

 

The audio interface market is fiercely competitive; as a manufacturer, you simply have to be better or cheaper than the competition because you have to sell a lot of units to make a living. A DI box is very useful for most guitarists.

Normally, you plug your guitar into an effects unit input using a 6.3 mm jack, and the effects unit output goes into the amplifier. A microphone is placed before the amplifier to pick up the signal and send it to an analog mixer or into the XLR MIC input of your Audient iD4.

The problem with the iD4 isn't the DI, but this: The iD4 JFET instrument input was designed to emulate the input stage of a classic tube amplifier, giving your guitar or bass the perfect sonic foundation from the very first note.

Spoiler: What exactly is a DI box?

What exactly is a DI box?
The basic task of a DI box is to transform an unbalanced, high-impedance signal into a balanced, low-impedance signal.
February 22, 2019 | 3 minutes reading time

Excuse me? Low resistance, high resistance – co(h)mic?

Every output (for example, from microphones or instruments) and every input (for example, from mixing consoles, amplifiers, speakers, or headphones) has a specific resistance. This is measured in ohms (Ω). The lower the resistance, the more current can flow. Resistance is measured for direct current (DC). However, audio signals are alternating current (AC). This "AC resistance" is called "impedance."

In modern PA technology, outputs are equipped with a low impedance to allow a high current flow; each input is equipped with a high impedance to minimize current draw. The smaller the (output) signal, the more important these factors become.

For this reason, professional microphones—which deliver the smallest signals in PA technology—have a low-impedance output of approximately 150–600 ohms. Instruments such as an electric guitar, however, have a high-impedance output, which can easily reach several kilohms. This is due to the design of the pickup coils.

The general disadvantage of high-impedance outputs is:

• Long cables cannot be used.
• The higher the output impedance, the more (negative) influence the cable has on the sound.

And what exactly is a (un)symmetrical signal?

An unbalanced signal requires two plug contacts or two cable conductors. One is the ground, the other carries the signal. In PA technology, this is typically implemented with a jack plug.

The disadvantage of this technique is that audible interference can be transmitted through the cable. For example, if a guitar cable is connected parallel to a mains power line, the 50 Hz AC signal will radiate into the audio signal.

To prevent this interference, balanced cables with three conductors/contacts are required. This is where the XLR connector comes into play. Pin 1 is ground, and pin 2 carries the signal. An inverted signal is also transmitted on pin 3. This is referred to as the "hot" and "cold" signal. The (audio) information is therefore out of phase on pins 2 and 3. However, all external interference affecting the cable is always in phase on both conductors and is therefore filtered out at the input stage.

The lower the signal level, the stronger these interference effects are on unbalanced cables. For this reason, professional microphones always have a balanced output. Instruments like electric guitars, keyboards, etc., which produce a significantly stronger signal, typically have an unbalanced output.

If you were to connect a long cable to a (high-impedance, unbalanced) instrument output—let's say 30 meters to the mixing console—it would degrade the sound and also pick up any interference.

That's why you need a DI box.

…and this is where a DI box comes in. It's connected to the instrument (with a short cable). The DI box output now provides a balanced, low-impedance signal that can be transmitted without any loss of sound quality or interference—even when using long cables.

Furthermore, the level is also adjusted. The instrument's high level is reduced to the very low level of a microphone and can then be connected to a microphone input on the mixing console.

https://www.shure.com/de-DE/insights/was-ist-eigentlich-eine-di-box

 

Last edited: Apr 9, 2026 at 12:25 PM

Audient iD14 MKII + ADAT expansion later

 

Okay, but the situation is still unchanged: I have the Alesis iD4, a cheap old interface, that has 4 instrument and 4 microphone outputs, 4 inserts, Midi in-out, and the input on that one never goes clipping no matter if you plug balanced or unbalanced into it, and you can adjust the input based on the meter showing the input signal. When, it seems if you want to use the more expensive iD4, you need to buy a DI box as well to be able to plug guitars into it, you only have 2 of these guitar incompatibile connectors, and monitoring the clipping is not even possible, because the meter doesn't show it.

So I still se no logic in choosing the iD4. The only legit reason that I heard as a pro iD4 reason is that the drivers and the latency management of the interface is good. That is, without doubt, but that's all. And that's why it has always been kept on the shelf in its box and why I will sell it to buy something different.