my receiver sub out is not working so how to connect to a sub

[raviera]

hi guys need suggestion
my denon 4308 reciever sub out or lfe out is not working and cannot be repaired and my polk sub psw 12 has lfe input and left and right rca jacks.can I use rca cables from my receiver preout left and right speaker output directly to the lfe input by using Yspliter means connecting y spliter directly on my reciever left and right preout jack converting stereo into mono and connect it to lfe input by doing this will any damage occur to my avr and sub or the othe option is put it in the sub left and right jack and set sub to off in my reciver.I cant find the answer anywhere on net.
thanks

 

[acoustics]

when you switch off the subwoofer output the lfe signals will be routed to your main LR .
Now in this case you should note that you can easily connect your subwoofer to the avr through the LR pre outs but your main LR speakers will also get this signal . So if your main LR speakers can't handle the lower bass frequencies then they might get damaged and the sound will also get distorted. if your Main speakers are good enough then you can go ahead. Do not use y splitter to convert the stereo to mono you could end up burning out the preamp board .
ususally what happens is that all preamp outs have an output opamp ic which gets damaged due to any short circuit etc. If you have any repair person who could do component level repair on smd devices get that opamp on the subwoofer output changed. plz look for repair manuals for the avr on the internet.

 

[raviera]

thanks for the advice my front speakers r polk rti a9 will it handle the low frequency. can I set cross overs by running sub with off option.in using 7.1 setup sub will produce low frequency for all the channels or only the fronts.