output power vs gain-volume settings

0 doesnt = 0 watts

i know how it works, but its hard to explain

one thing i think your getting at

single master volume is just a post gain with a set pre gain

think of the amplifier in 2 parts

the pre amp, where the tone shaping happens, and the power amp, where the signal is boosted to drive a speaker cab

Now, imagine the power amp, it itself is not controllable and is always at its max settings, however, the output of the power amp depends on the strength of the signal it recieves

the pre gain controls the signal level of the preamp, and the post gain controls the signal level just before it hits the power amp

hope that helps somehow

 

No, there's not really a "linear" relationship there.

The lower you set preamp gain levels, the harder it is drive the power amp stage to full output. That doesn't mean that an amp will put out more wattage when the knob is set to 10 versus being set to 8. Let me put it this way....I could set pre- gain at 10 and play softly and have no problems, or I could set it at 8 and dig in hard and it'll clip like a mofo.

In other words, you've still got the variable of the strength of the incoming signal.

Now, if you were to use a sine wave generator for the input signal, and the preamp output voltage was precisely matched to the sensitivity of the power amp, and the potentiometers on the preamp were of a linear taper design........then yeah, setting pre- gain to 5 would cause the power amp to generate half the output wattage compared to setting the pre- at 10.

But there are no pre-amp power amp configurations that are built like this - there's no need to. Preamps and power amps often have clipping indicators, and even if they don't the sonic indicators are pretty obvious.

Every bass amp I've ever played through will hit peak wattage a long ways before getting the volume knob to "10".

 

Something to understand - potentiometers come in different designs - linear taper and audio taper.

Linear taper means that at the 20% position, the pot passes 20% of the signal; at the 50% position, the pot passes a 50% level....and so on

Audio taper means that the relationship between position and output has been adjusted to compensate for the way human ears percieve volume changes. Instead of a straight line like a linear taper, it's a curve.

So the knob position on an amp can't really be interpreted to represent a certain percentage of output directly, because a knob position of "5" on an audio device does not mean that the potentiometer is passing 50% of the signal.

Any device dealing with audio will use audio taper pots, otherwise it will seem like it doesn't react the "right" way to adjustments because of the way our ears percive sound and volume.