I unintentionally used 4ohm speakers on my 8ohm Sony reciever. The speakers were given to me, I was told they were 8, but I just got the bright idea to test them myself, and they are 4 (actually tested at around 3.7). I am quite worried that I might have seriously damaged my reciever and it won't function properly when I connect properly rated speakers. Is this the case, or is there a good chance my reciever is fine?