I am experiencing a strange problem with my pair of Wharfedale 9.4s. If the volume of my RA-04 is turned past 8 o'clock, the amp cuts out. This never used to happen (in fact this morning it was still working). I have determined that the problem is with the right-hand speaker - if one unplugs the right-hand speaker and runs the amp through the left one alone, everything is fine. I have also tested the speakers with another old amplifier, only to experience the same problem with the right-hand speaker.
Further experimentation showed that if I removed the gold/copper plates that join the LF driver and the tweeter at the binding posts, and ran the speaker through only one of its drivers, then the amp did not cut out. I experimented with replacing the plates with some speaker cable - same problem. Finally, I opened the speakers (simple hex screws keep the LF driver in place) to find no shorting wires or loose connections, even at the crossover.
Many thanks in advance for any suggestions.