The price of the interconnect is irrelevant. You need to tell us the output impedance of the preamp and the input impedance of the amps as well as the current drive capability of the preamp.
"Y" Connector: Can Split A Signal How Many Times?
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Your preamp has pre-outs for amps for two speakers, you use two "Y" connectors to create the ability to connect amps for four speakers.
How many times can you split the signal before it starts to degrade?
.
Your preamp has pre-outs for amps for two speakers, you use two "Y" connectors to create the ability to connect amps for four speakers.
How many times can you split the signal before it starts to degrade?
.