Hmm. For your solid state amp to go into protect mode, either it is itself broken or it is putting out a lot of power into the right channel.
Assuming the solid state amp is not broken, you should be hearing the power that it is putting out in the right channel unless that power is outside the audible range or outside your speaker's performance range. Unlikely that it is high frequency. More possible that is could be subsonic.
If so, it could be originating from your cartridge or turntable, although the turntable is less likely because it would probably affect both channels. Maybe your cartridge is going bad. How old is it?
Or it could be your phono preamp. Like something involved with RIAA equalization?
If your linestage preamp is working properly, it would transmit the subsonic signal to the solid state amp and cause it to shut down. If the linestage preamp is somehow handicapped from effective transmission of subsonic signal, then the solid state amp should keep working and not shut down.
Have you tried swapping left and right channels between the turntable and the phono preamp? How about between the phono preamp and the linestage preamp?
Assuming the solid state amp is not broken, you should be hearing the power that it is putting out in the right channel unless that power is outside the audible range or outside your speaker's performance range. Unlikely that it is high frequency. More possible that is could be subsonic.
If so, it could be originating from your cartridge or turntable, although the turntable is less likely because it would probably affect both channels. Maybe your cartridge is going bad. How old is it?
Or it could be your phono preamp. Like something involved with RIAA equalization?
If your linestage preamp is working properly, it would transmit the subsonic signal to the solid state amp and cause it to shut down. If the linestage preamp is somehow handicapped from effective transmission of subsonic signal, then the solid state amp should keep working and not shut down.
Have you tried swapping left and right channels between the turntable and the phono preamp? How about between the phono preamp and the linestage preamp?