Behringer Ultra-DI DI400P Passive Direct Injection Box

Armando Bravo

June 27, 2025

Good choice!

Have not had a single issue with it! Great price and more than worthy! Good sturdy quality.

Great

6 years later, this still works!

I bought this about 6 years ago and have used it for well over 200 plus shows, plus endless practice sessions and the device still works perfectly with no hum or sound residue. I am actually quite surprised at the durability and longevity of this little box. So much so, that I remembered I never reviewed it on here. If you are contemplating on this, just get it. The value pays for itself in endless durability.

Bought 2 as price was good. UPDATE: Frequency response measured.

I previously wrote:

“First thing I noticed was how light they are. As the owner of West Michigan's only while you wait tube amplifier service company, I'm well aware that for a transformer to avoid saturation at low frequencies, it requires a good bit of iron core, and it needs to be the right kind of iron. That means weight. My suspicion was aroused by the very light weight, so I decided to save all the packaging, just as I was about to toss it. From their product description: " Ultra-flat frequency response due to renowned BEHRINGER OT-2 transformer" “ -- that was part of my original review, which was rather negative based on a quick oscilloscope-and-signal generator sweep test. I have since had the opportunity to run these two boxes over a proper calibrated audio test system, (Audio Precision 5xx) and so I need to update my findings.

Properly loaded (Hi-Z in, 600 ohms balanced out) these boxes do measure a fairly flat response as promised, with one caveat. The higher you go with input level, the worse the low frequency response gets. At 1Vrms in, things looked pretty good down to 20 Hz. As you go up in level to 6.3Vrms, the response below 50 Hz drops, with the -3dB point being at about 18 Hz. The high side of the response looks pretty flat out to 30 kHz with a standard frequency sweep. I did not check for ringing with a square wave. There is no compensation network or attenuator built in.

Conclusion? These are not for critical work. They are a decent cheap DI for low-level instruments, but I would not recommend them for high-level active instruments (i.e. a modern bass with 18v preamp, or amplifier outputs above a few watts) as the low end starts to walk away. I’ve decided to keep these two, but will also keep in mind their limitations.