Originally Posted By: Micah


So now I'm left wondering, how could an amp that only produces a little over twice the power make that big of a difference in percieved volume? I know that the Denon had to have been making somewhere between 100 - 120 db's of output because at SRoodes house he was using a Denon similar in power rating as mine, and he showed me on his SPL meeter that we were listening at 100 db's. And we have the same equipment. And I have fully grasped notion that the volume position has nothing to do with how much power is being used between the two amps because of the power curve at play. But the way I understanding it, if my new amp can only add an extra 3 or 4 db's increase in volume, then why is the percieved output so much greater?


Mica –

Well…. to understand your perception holistically, the answer to your question is a mutually exclusive dichotomy of emotion and logic. Your perception is a mix of real and non-real and both. Depending on what perception you are referring to, it may just be an emotional response, or it may be very real. If you are referring to dynamic peaks at an already loud SPL, it probably is real. If you’re referring to constantly moderate SPL with little to no dynamic peaks, then it’s probably a perception based on some form of emotional response.

When speaking to the peaks, and why an outboard amp would have “real” gains over an integrated amplifier that is housed in an AVR such as your Denon, there are a couple possibilities that are logically supported. The outboard amp more than likely has a more robust power supply. Just take a look at the PSU in the Krell dakkon posted above. Remember, the power supply is where the amp(s) get their power from. Amps do not generate power; they simply change the amplitude (add gain) of a millivolt signal they receive from the pre-amp, (which in some instances converts a sine wave that represents frequency, into millivolts). The PSU converts power from the electrical wall outlet to usable power for the amps. As the sine wave goes up and down, the power requirements to match it will follow.

Voltage will dip and rise with the sine wave due to an instantaneous flow of electrons being allowed to pass to the speaker drivers, through the coils and back to ground. (think of your thumb holding back a steam of water in a garden hose with each water droplet being an electron under pressure from the water main). The recovery of voltage (pressure) is dependent on the current being supplied by the power supply. The variance of this dip and rise is determined by the potential current supplying capacity of the power supply and what type or level of capacitance it has (think of current as the number of electrons, or water droplets in the garden hose and water main). As you apply gain to the sine wave, the domino effect is more needed electrons at each speaker driver. When the power supplies current supplying potential has been met, clipping occurs. Obviously, when there is a greater supply of available current for the amp sections, clipping will occur later, verses sooner.

Then of course there’s always the individual rating of each component. Without looking real hard at the score card and spec of each, it’s hard to determine exactly how much “real” power each amp can supply. A rating of 100 WPC is completely meaningless without supporting measurements.

I’m obviously not an expert of amp design, electrical theory, or philosophy, but a student of all. In other words, I don’t fully appreciate what I don’t know that I don’t know. However, I do know I don’t know shit and you should take what I say for what it is, which isn’t much.