Hiya Sugarplumsss (very interesting name.....how did it come about?)
I'm sorry to say that I'm not an expert and can't categorically answer your question correctly. But two points :-
....for myself, I'm always trying to connect things together, messing about, that may or may not be designed to work together, but, I've never really had any problems 'cos I do at least think that I have a modicum of common sense...I've not yet put mains current into a guitar pickup !!!!!
... I've had lots of Behringer bits and pieces, from guitar pedals up to a Bugera amp, which is their professional jobbie, all of which have been knockout, low price or not. The Bugera HA400 headphone amp has 4 stereo 1/4inch jack inputs, so, if my guessing is good enough, you'll need a stereo to stereo jack cable.
So, I'm sorry I'm not 'expert' enough to guide you and hope this might help just a bit.
Also, I'd like to take this opportunity of saying how much I have enjoyed your questions for such a long time. I never have an answer for you, I'm not technical enough even though I would like to be. I'm amazed at the knowledge of some the contributors, their willingness to give their time up and I have learnt quite a lot about my T4 from the responses to your questions.......so - thanks for your questions, thanks for the answers and keep 'em coming !!!
Very Best wishes - Jim