my amp is a marantz pm-32 and i have had it for about a month, i added a nad 5240 cd player to my system on friday, it came with no power cable so i got a cable with the right voltage and so on. On saturday i noticed one of the speakers was underperforming and over the afternoon it led to just producing a faint distorting warble, at first i thought it was the speaker, then when i changed over the speaker channel it did exactly the same. Then today i unplugged one of the channels and i got a spark off it. Has the channel now shorted out ?? Any solutions would be most welcome thanks