Ignorant Question about wattage output

[Bigskybassguy]

Putting my ignorant question simply: is the MASTER Control actually the wattage output control?

Take a bass head in Bridged Mode: say it puts out 900W (8 ohms) or 1500W (4 ohms) with the MASTER Volume Control cranked to 10 (I assume).

With the MASTER Control dialed back to 5, is that amp putting out HALF its wattage (450W & 750W)

So with a 350W cab, I'd best not exceed 5 on the MASTER Control?

It can't be that simple! With the master control on 5, then dial up the DRIVE (gain) to 10, it's gonna get WAY louder.

Does cranking the Drive control add to the wattage output? louder is louder, right?

[Bass_Pounder]

You were right when you stated "It can't be that simple"

Amps are rated at their ability to put out clean wattage. When pushed into clipping, amps can put out far beyond their ratings.

Depending on your gain structure, you can be putting out your amps max at 5 or below on the knobs.

It's best to listen to your speakers - they will let you know when they are being overworked.

[bongomania]

The Master knob is usually just a passive volume pot that turns down the output from "maximum". So if you feed a steady sine wave at a fixed voltage into the amp, then the Master knob will appear to control the wattage output. But even then, the pot is not likely to be perfectly linear, so turning it to "5" probably won't reduce the wattage to 50%. Plus, music signals -bass guitar especially- vary hugely in their voltage swing. So let's say you slap/pop the low E really hard, and the input gain (drive) on your amp is cranked up, and the amp momentarily generates 1.5 x its rated output, and you turn the Master knob down to 5, there are so many unknowns in there that the only way to know whether your speakers would get blown is if they DO get blown.

[billfitzmaurice]

Originally Posted by Bigskybassguy

is the MASTER Control actually the wattage output control?

No. It's a volume control. There are no controls on your amp that actually limit the amp to a given power output.

say it puts out 900W (8 ohms) or 1500W (4 ohms) with the MASTER Volume Control cranked to 10 (I assume).

The position of the control makes little difference. Some amps can reach maximum power with the controls set at 5.

louder is louder, right?

Right.

[will33]

A lot of knobs on a lot of amps are anything but even from top to bottom. Sometimes you have to use your ears instead of reading the numbers.

If it sounds stressed or overworked the answer is to quit demanding so much from it, give it a joint or a glass of wine and go a little easy on it....just like your girlfriend.