How to Connect Pre Amp to Audio Interface USB


Their are many ways to connect your pre amp to your audio interface, however, their is only one way that is the right way. And by the “right way”, I mean the way that is going to cause the least amount of problems for your recordings.

This is a general guide to hooking up a pre amp to an audio interface that connects to your computer via usb but the principles should apply to most any pre amp and audio interface.

So first what you need to connect your microphone to your computer is an audio interface. This could be a soundcard such as the much acclaimed M-Audio Delta Audiophile series such as the 2496 or the 192 models. These are “classic” soundcards that go into the pci slot inside your computer. You can either connect to them digitally with an S/PDIF cable or rca cables. If you’re reading this, you probably don’t have this set-up, because it is quite an old approach to home recording (but nonetheless a good and reliable one).


The second way of connecting your microphone to your computer is with an external audio interface that plugs into the usb ports on your computer. There are many budget audio interfaces to choose from such as the:

(1) Focusrite Scarlett 2i2


(2) Alesis IO2 Express


(3) M-Audio M-Track.


Each of these is between $100 and $150 US. The nice thing about them is that they all provide phantom power to power your condenser mics so if you’d like you can plug your mic straight into your audio interface and be ready to record. Another nice feature is that they all record in 24 bit/48 khz.

A not so nice feature of cheap audio interfaces is that they don’t sound great. Don’t get me wrong they sound okay or even good depending on a number of factors I don’t care to get into right now because their are many. Usually what people have done to get around this is to connect a decent pre amp to their audio interface, which is probably what you want to do.

All you’re going to need to do that is this:


It’s a 1/4 inch TRS to TRS patch cable. These cables are not to be confused with speaker cables, instrument cables, guitar cables or insert cables, which all happen to look the same. These cables are usually the most expensive with the cheapest retailing for $20. Just head on to your local music equipment store and be sure to ask the dude with long hair to point you in the right direction. Keep in mind different brands cost different prices depending on the construction of the cables and/or if they provide a lifetime warranty or not. If you’re just using them in your bedroom studio they shouldn’t suffer the same abuse as guitar cables used by a touring rock band, so you don’t really need the lifetime warranty.

So now you’ve got the right cable, what do you did with it? Simple. On the back or front of your pre amp you likely have a line out, plug one side into there and on your audio interface you have a line input, plug the other side into there. Boom! You’re in business.


Hold up just one more thing, since you just plugged a good pre amp into a not so good pre amp you’re going to want to make sure you’re not so good pre amp doesn’t affect your sound quality. You can do this by turning down the gain on your audio interface all the way down to 0.


In fact turn off the phantom power in your audio interface’s pre amp so that you’re not using its amp at all. The reason you’re doing this is because then you’d be putting your vocals through 2 amps and unless this is the sound you’re going for then you don’t want to be double processing the vocals.



Andre is the head audio engineer at ADG Mastering, which he helped found in 2012. For the last 10 years, he has made it his mission to empower aspiring artists and musicians from around the world. You can see more of Andre's writings on our Blog.


  1. hey quick question, upgrading my old interface and ecquipment to top knotch gear, but is this always the case.. your mic should be strickly powered by the pre amp and not the interface at all???

    • Hi Orion,

      No not necessarily. If you have a really good interface with a preamp than you don’t need another preamp. For example, the RME Babyface is a really good preamp and interface.

  2. Thanks for the article but the picture of the so called TRS cables are not TRS. TRS stands for Tip, Ring, Sleeve and the jacks pictured don’t have a “Ring” so they are not balanced and/or not stereo like TRS jacks should be.

  3. So would it be more ideal to just use an XLR if the interface has the capability of connecting to the preamp that way instead of a using TRS?

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