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I've bought a Behringer Ultragain 2200 preamp and want to plug the guitar in. I know that usually when I'd plug my guitar to the amp or audio interface the input impendance would be around 1 milion ohms and this preamp I bought has input impendance of 60k ohm (as I read in the manual).

With 60k impendance compared to 1 milion I reckon it will probably be too less to plug my guitar in. But there's the other thing. Manual says that I can use this gear as a DI box. Does it mean that my high impendance signal from electric guitar passing through the input of the Behringer's 2200 preamp will be turned into low impendance? If yes, it's understandable its line load is about 60k ohms and not 1 milion as it would be in amp and audio interface.

Usually DI boxes' output impendance is around 600 ohms. If my gear works the same way, then I'd understand why its line input impendance is around 60k. This way it would be ratio 100:1 (60k:600).

So basically my question is, will my gear (preamp) turn the high impendance of my instrument down as DI boxes do and therefore process it with its 60k load, or maybe it doesn't turn it down and the guitar signal will be too hot for the interface (because of the 60k load instead of around milion)?.

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Yes, you can plug in your guitar. The signal will be converted to Balanced Output. They have set it up to accept different instrument levels.

5.3 The ULTRAGAIN PRO as a direct-injection box When electrical signals delivered by instruments such as guitars, keyboards, etc. are transported over long unbalanced lines, the transmission quality may be affected by hum or other interference signals induced in the cable. This problem is usually encountered in studio or stage environments, where long cable lengths and magnetic fields of great magnitude may produce interference.

So-called direct-injection (DI) boxes are used to counter this effect: the DI box converts the unbalanced signal coming from the instrument into a balanced signal that is sent over the line. Interference induced in balanced cables is then eliminated by a subsequent differential amplifier (as explained in chapter 3.3).

Using the ULTRAGAIN PRO for this kind of application is easy. Simply connect the line output of your keyboard to the phone jack input on the ULTRAGAIN PRO. Then use the ULTRAGAIN PRO’s balanced output to send the signal to a stage box or other transmission chain. You can use both the XLR and phone jack connectors of the ULTRAGAIN PRO. Set the unit to LINE mode, with any additional functions switched off (an exception being the OUTPUT control which can be used to adjust levels, if necessary)

  • There is mention of guitars in the first paragraph, but then there's "connect the line output of your keyboard..." so I'm not sure that the manual really makes the claim that you suggest it makes. – Your Uncle Bob Jul 15 at 20:53
  • @ Your Uncle Bob yes, they are vague about it, however because they included the phrase "instruments such as guitars, keyboards, etc" and then used the keyboard as an example, I think we can reasonably assume that the example was taken from that list. Further reading of the instructions as well as the marketing material leads me to believe that their intention was to make it functional for many purposes, including replacing the use of a DI, which is commonly used for instruments such as guitar and keyboards. – Alphonso Balvenie Jul 16 at 4:29
  • Thank you for you answer! I read manual and this part when they mention guitars and keyboards and then in the example only mention keyboards confused me a little, as if they weren't sure about it. So the guitar signals' impedence will be attenuated to less than 1000 ohms I suppose, right? As it is done in most of the DI boxes (their output is around 600 ohms). Then this signal will go through 60k ohm line input circuit. Am I right here? – Toby Jul 16 at 9:19
  • The input signal is processed, not merely sent through a transformer like a DI. Without looking at a circuit diagram there's no way to tell exactly how they're treating the input. The output stage is indirect from the inputs and set to a Low Impedance line level signal with a variable voltage range and a listed output impedance of 60 Ohms. – Alphonso Balvenie Jul 16 at 20:18
  • Ok. Since the output (either from line or XLR connection I suppose) is only 60 ohms I will connect it to the interface with the Mic setting on that have around 2k ohms input impedance. That will be ratio more than 1:30. It's kinda interesting cause that would mean I will have set mic setting on my audio interface while processing guitar signal that got attenuated to 60 ohms by preamp. Interesting. – Toby Jul 17 at 9:40

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