Plugging in external preamp to US-122

[Guitarer]

Are there any line-ins to use an external preamp? I've got 2 XLR inputs along with 2-1/4 ins, and then 2 1/4 "inserts" (Are those line-ins?)

If there aren't any, can I plug the external preamp into the built in preamps and just have the gain all the way down on the built in ones?

I realize I should probably just get a new interface, but I don't feel like spending that much money right now. I just wanna work with what I've got. I'm wanting to hook up a DMP3 to it.

 

[XLR]

The 1/4" inputs are selectable for line level or guitar level with a switch and can take balanced or unbalanced signal (TRS or TS plug). The preamp gain knob still acts on the incoming signal but you just turn it down and use the gain on the outboard pre. I've used it that way a lot with a pair of Electro Harmonix 12AY7 tube pre's and it worked fine. Don't see why you couldn't use the insert as an input, with the right connecting cable, bypassing the internal preamp, but it'd be unbalanced only.