If you haven't already, try the MM setting on the back of the amp.
Rega p3 and Yamaha AS1100
New rega p3 and Yamaha AS100. Playing moderate volume between 8 to 10 o'clock runs great good quality sound. As soon I set to 11 o'clock volume on my amp, speaker start to produce chopper and vibration sound. Checked the tracking force and balance of the TT and they are ok. Run my amps on my Spotify feed at high volume and it's ok. Checked table vibration and it's ok. I am stuck and don't know we're to start. Any help out their will be greatly appreciated.