Hi hietpas,

Another reason pre-pros and separate amplifiers cost a lot more is that you have to have two separate power supplies, two chassis and so on. There's a lot of duplication, which adds to the cost.

There's also an historical tradition that component parts chosen for pre-pros and separate amplifiers are of better quality--better output devices, more sophisitcated DACs, better shielding and so on.

These may or may not make any audible difference. Typically, a separate pre-pro should have a lower noise floor because there aren't any high-power output stages, which are in the power amplifier.

With inexpensive pre-pros, I'm not convinced there would be any audible difference compared to a good AV receiver.

As Micah has pointed out, a separate power amplifier also allows for much greater power output, better cooling and air flow, beefier heat sinks and in more costly models, really good output devices and larger storage capacitors so the amp can drive very low impedances with lots of current and no overheating.

Regards,

Alan Lofft,
Axiom Resident Expert (Retired)