Re: what speaker cable?
From PROCO website;
"SPEAKER CABLES
Make sure that the cable is unshielded and of at least 18 gauge wire. Shielded cables are not good for speaker hookup because they can’t carry the current demands of a loudspeaker. They can also cause problems because of their capacitance, which can result in amplifier instability or breakdown. Be especially careful of phone plugs on speaker cables -- check for loose tips, broken insulators, etc. As before, the basic testing process is the same as that for instrument cables."
...I like Proco products. I have a massivvely thick and well built speaker cable called the "PROCO GaURDIAN " that was very pricey new,for my best rig.
I've got good qaulity thick gauge cables for all my speaker cabinets(and have also rewired my cheap stock speaker cabinet wires). I hate cheap crap.