[Doublej]

True or false, per dollar spent the greatest return on power conditioning is when it is applied to the source components as opposed to the amplifier.

My faulty(?) logic is as follows:

Amplifier power supplies are usually designed to handle power variations better than  source component power supplies and since source components draw far less power they will require smaller peak current capabilities in the conditioner, so you get a far greater return by applying power conditioning to sources.

[TheChairGuy]

Sources and preamps need less powerful conditioning, so it's a bigger bang for the buck just from a pure $$$ expenditure point of view. 

Amps typically require something without any current limiting.....which will cost you more.

Conditioning with 'digital' amps, however, seems to be essential to make them sound great.  Not quite as much so with well designed conventional SS or tube amps.