Although I'd recommend soldering them after you splice them,You can splice the wires together and then wrap electrical tape around the individual spliced wire ends without soldering them.You might consider purchasing some inexpensive wire nuts that will twist on the ends if you don't solder them, this is an inexpensive and easy solution. You just have to buy the right size. This will not look as good but will work well.
I spliced mine to test it first and then once I knew they worked, I decided to solder them for an even more solid connection and then taped the individual ends.
I spliced mine about 1/4 or maybe 1/2 inch.
My unit works great now! You're will as well.