"Turned the amp off, dac on and gone"
Obviously ;-)
If you think the fault lies within the amp - with it turned ON and nothing connected to it other than speakers, lift one side maybe 1/2 " or so and let it fall back down, try both sides. If theres a loose solder joint or connection inside that can be exited by the quite small vibrations form bouncing kids on the floor, above will certainly expose it.
Best of Luck
Peter
Obviously ;-)
If you think the fault lies within the amp - with it turned ON and nothing connected to it other than speakers, lift one side maybe 1/2 " or so and let it fall back down, try both sides. If theres a loose solder joint or connection inside that can be exited by the quite small vibrations form bouncing kids on the floor, above will certainly expose it.
Best of Luck
Peter