My experience has been that Void is the space of the “breathing in” negative energy in which all potential exists, without form, and that one thing people call Source is the bindi/point of first creation (“breathing out”), that transcends all polarities and surpasses the prinaciples (vibration, gender, cause and effect) described in the Kybalion BUT which is still by way of having quantifiable aspects and being approached quite easily in a relatively normal state of mind - Joe Vitale describes it as a white board, and it can be worked with as such.
If Source has come to mean some Demi-urge linked to a small regional tribal godform, that leaves out as ever all the worlds and all the civilisations prior to Moses/Akhnaten/Zoroaster who had no such concept.
Going into Source past that point, you truly lose your mind (as in loss, not going insane) because as @anon27714670 says, you cannot technically “add yourself” to it, as you already are there and are originating from there - but the stronger your ego and will, the longer you can hold some aspect of basic You-ness (desire, and will) in order to operate with a substantial amount of its innate power that transcends cause and effect, time and space whilst still being able to direct it in one way, and not another.
I typed some of my experiences and thought about this in this thread: "In Darkness Bound" And The Psychology Of Demons.