found a headphone amplifier, that i needed, for $8 at a pawn shop. Surprisingly decent. Battery powered. Want to run in a chain with my tuner, loop pedal, and sansamp. The problem is, when i do, creates all sorts of grounding issue noise. I don't need it battery powered, it's just for practice at home. Can i disconnect the battery adapter, and solder those wires to a transplanted female dc input? It seems like it would work that easy, but i don't know all the particulars.... could i also run some new wires in parallel to the battery, to retain the use of both? Lastly, if i have to order the female dc input, does anyone know what the hell size it is? Below are pictures of the box, and an option i found on eBay.