Hello mate,
my system is the JBL 7 Speaker.
You won't lose your speakers all you need to do is find the wires leading to the amp from existing system.
Then from the Amp find the wires going to the speakers.
Remove amp and cut plugs off and match/join wires from system to amp wires, thus cutting out amp.
I made a note of wires etc I will find them out for you.
All the best Paul.