Typically on an amp that gives you an option for speaker A and B connections it’s for two sets of speakers and it’s intended to be a switch to pick from one pair or another. I can’t speak for the Marantz but some amps will only let you pick one or the other and not both, so I’d suggest only using A or B to your Whatfedales to begin with.
On your Wharfedales what are you currently using for speaker wire now? If you’re thinking of purchasing different wire what is your budget and what type of music do you listen to? If you have decent cables not start with replacing the jumper straps that are on your binding post first with some wire jumpers. If you want to see if jumpers really make a difference to start with make your own first.
All cables are essentially a tone control so it comes down to personal preferences. If you’re looking to change what you currently have I’d suggest just to buy a single set and use jumpers instead of two single pairs which is what most cable manufacturers recommend as well. Buying used is wise as cables depreciate a lot. If you’re using the stock power cord I’d start there first. It is best if you find a cable brand/flavor you like to stick with that manufacture throughout your system. I personally use several in my system but you have to know what your listening for and it is a lot of experimenting and sometimes it works and sometimes it doesn’t. Buy used so you can experiment and if you don’t like resale at no or very little loss.Trust your own ears.
