Set up the drum set near the stereo. Y-cables can be as short as 6 inches or as long as 9 feet. Set your drum set close enough that the cable has enough slack to reach the inputs of the stereo receiver.
Locate the connection points on the stereo and the drum set. The control panel of the drum set will have a headphone jack that doubles as an output jack. Your stereo receiver will have multiple RCA input jacks located in the back of the unit. Labels for each set of jacks will include "CD," "DVD" or "AUX."
Connect the drum set to the stereo. Insert the 1/4-inch TRS end of the cable into the headphone jack of the drum set control panel. Select a set of RCA inputs on the back of the stereo receiver and insert the RCA end of the Y-cable into the jacks. Match the color of the input jacks with the cable when making the connection.
Adjust the settings on the stereo. On the front of the stereo, select the input that is connected to the Y-cable. Set the master volume of stereo so that future adjustments only have to be made from the drum set control panel.