DC entering my amp?

I have an SPL Performer 800 amp that has a DC protection function. Once every week or two that function gets tripped, not necessarily while playing music. I use good quality cables and the connections are tight. I have a tube preamp ahead of the SPL so thinking that could be it. It is single-ended output only and the SPL is balanced only so I use the single-to-balanced interconnects from Benchmark Media. Source is a Lumin streamer and an outboard DAC. All components are plugged into an Audioquest Powerquest unit. Harbeth speakers connected to amp via good Kimber cables. I leave all components on all the time for the most part.

Any ideas on where/how to look for the problem? I did once just leave only the amp on for several days and it didn't trip.

Ag insider logo xs@2xitball

@cleeds I only know because the amp has a particular protection for DC and that is what lights up. It has a separate overheating protection and that is not being triggered. Speaker wires are all banana terminated and all clear of strays (I checked them).

@itball Pay attention to what @gs5556 says- he is giving you really good advice for getting to the bottom of this. I would add that if the preamp isn't connected and the DC Offset at the speaker terminals goes up, then the amp is at fault.

Thanks everyone. Will work to do some DC measurements and see what it turns up.