No, It will not be the same load for the amp. But, it's better to load the amp than the preamp. The amp will see a higher impedance, if your using a tube amp then the higher the better(with the exception of a few, Music Reference and Decware just to name a couple). If your using SS for amps then it's still just fine. The best preamps do not have a buffer output stage so, even if they have dual outputs, they're just parallel. This puts a load on the preamp out, that far more hurts the sound of the system than the amps... cause this way makes your impedance differ into your main amplifier and we don't want that.(course in some instances it may be better to alter the impedance into the main amps) If a preamp has a buffer output, then by all means use the second pre. out but, the pres. that have this buffer are not near as transparent and resolving(usaully entry level pres. or home theater stuff, this makes them more bullet proof but compromises the sound)) These are my opinions and thats all. There are some that would argue this with me but, in my room and my gear it always works best to hook the sub up high level to either the amp terminals or one of the main speaker binding post.Just try both ways, I've heard it work both ways actually but, in my room as I said before, it works best high level and for most of the people I know.