I think what John was saying is that amps don’t change sound. Not AV/Pre amp processing. Anyone with any common sense knows that the manor in which a processor manipulates a signal can have significant changes in how it sounds. After the signal gets manipulated by the processor, it goes to the amp and the amp does nothing but ‘boost’ that signal. It is this part of the chain where there is no coloration occurring. An extremely overly simple way of looking at it is to remember that the signal is nothing but a mix of electrons traveling from point A, to point B as pulses. An amp does nothing more than piss off these electrons and get them moving faster with more force. It doesn’t add or subtract the number of electrons in the pulses. The processor on the other hand does screw with them. It changes the quantity of electrons, the shape of the pulses and also directs them in different directions.
The discussion regarding ‘how much’ amplification is needed is one that I tend to disagree with folks who say all you need is a few watts of power. But I tend to listen to music / movies a little louder than most. Loud enough to where I need my cell phone set to vibe and stuck in my pocket……Even this discussion gets morphed into a ‘how many watts do I need argument’ when in fact it has little to do with watts, but the current in which the wattage calculation is based off of. Current has more an effect than voltage when considering usable power. You can in theory have an amp that is rated at 300 watts that won’t drive squat whereas a different amp rated at 25 watts will do just fine. Even though the voltage is adequate, if there is not enough current to maintain that voltage, voltage will drop which will reduce wattage. Watts = Amps x Volts or P (watts) = I (current) x E (voltage)
Another way to look at this is to apply the theory of internal combustion engine power and their application in vehicles. A diesel engine rated at 300 hp will move a 10,000 pound truck much more efficiently than a gas engine producing 300 hp. The reason being is that the diesel engine develops 300 hp at a much lower rpm because it has much more torque. The 300 hp gas engine has to spin at a much higher rpm to develop the same HP. Comparatively speaking, torque would be current, whereas wattage is comparable to HP. HP is nothing more than a mathematical sum of torque over time. T (torque) X N (rpm) / 5252
Let’s say this 10,000 pound truck is cruising along at 60 mph pulling a 5000 pound trailer and you come to a hill. If it has the diesel engine, the truck maintains speed up the hill and the rpm stays fairly constant. It does this because it has the torque to maintain this speed. The same scenario but now the truck has the gas engine with the same HP rating. The truck starts to slow and then downshifts, which raises engine rpm. Pretty soon the engine speed is pegged at red line and the truck continues to slow. Even though the HP is the same, the truck can not pull the load as effectively as the diesel engine powered truck…….it just doesn’t have enough torque.
So now to relate this analogy back to audio…….
You are watching some bass heavy movie with a big action scenes and your speakers are large towers that have multiple and/or large drivers. During normal volume scenes, everything is fine and it’s plenty loud enough. But when the action kicks up and if your amp is rated at 120 watt but has low current, the action scenes do not play as loud as the sound track is supposed to play and the speakers clip (truck slows down). But if you had a similar rated 120 watt high current amp, the action scenes make you reach for the remote to turn it down.
