I just hooked up my new 6300. I have an ALS 600 which I previously ran to a kenwood through an ARB-704. I am unable to key the amp using the ARB-704 however I am able to key the amp directly from the 6300 to the Amp. My question is when directly connecting the 6300 to the ALS600 should I also be using the RCA plug into the ALC on the amp and radio or is that not necessary? Should I be using the ARB-704 or is that unnecessary as well?