Can I turn it to 11?

Kwesi · #1 10-06-2010, 09:27 PM

This has always made sense to me but I haven't yet had the chance to try it out so I'm asking you guys:

If your amp is rated for 500 watts at 4 ohms and you're running a 4 ohm load that can take 800 watts RMS, shouldn't you be able to max out the gain and master volume with no ill-effects to either the amp or cab?

MIJ-VI · #2 10-06-2010, 09:37 PM

As long as the power amp isn't clipping...

Kwesi · #3 10-06-2010, 09:49 PM

Quote:

Originally Posted by MIJ-VI

As long as the power amp isn't clipping...

I don't get why an amp would be designed so that it couldn't be run at maximum volume if given the opportunity. I could understand clipping the input if you've got a really hot, active bass but that's about it.

brendanbassist · #4 10-06-2010, 09:55 PM

Quote:

Originally Posted by Kwesi

I don't get why an amp would be designed so that it couldn't be run at maximum volume if given the opportunity. I could understand clipping the input if you've got a really hot, active bass but that's about it.

For the same reason a car isn't designed to be driven with the gas pedal floored. You can do it for a little bit, but over time you're adding wear to your engine/amp.

Kwesi · #5 10-06-2010, 09:58 PM

Quote:

Originally Posted by brendanbassist

For the same reason a car isn't designed to be driven with the gas pedal floored. You can do it for a little bit, but over time you're adding wear to your engine/amp.

So, am I getting 500W at 4ohms with everything maxed or before that? I mean, if something is rated for a certain wattage it should able to reliably handle that power for at least the period of the manufacturers warranty.

James Judson · #6 10-06-2010, 10:08 PM

Your amp is already working at maximum volume. All amps are working at maximum. You control the amp with a potentiometer (gate) at the front of the preamp. Don't believe me??? Turn your axe volume all the way down, now turn the amp all the way up. No sound??? Where's my 500 watts??? Your amp is all the way up (maximum) but no sound. The gate is closed on your guitar. Sometimes there is a volume control between amp stages. This is usually called "master". The amp manufacturer does not know what you may plug into that amp so it is designed for a range of signals (passive, active, etc.). So cranking your amp up to 500 watts (11) may not get 500 watts to the speakers. Maximum volume may be 1000w on a 500w amp but a very distorted 1000w. Do you want all that distortion??? I know some guitards that do.

Ric5 · #7 10-06-2010, 10:13 PM

Quote:

Originally Posted by Kwesi

This has always made sense to me but I haven't yet had the chance to try it out so I'm asking you guys:

If your amp is rated for 500 watts at 4 ohms and you're running a 4 ohm load that can take 800 watts RMS, shouldn't you be able to max out the gain and master volume with no ill-effects to either the amp or cab?

Turning 500 watts all the way up ... I hope you got some good earplugs ... Also pretty much any amp run with the volume maxed with produce a crappy tone.

There is only one good road to more volume ... PA support.

bongomania · #8 10-06-2010, 10:18 PM

Quote:

Originally Posted by James Judson

Your amp is already working at maximum volume. All amps are working at maximum. You control the amp with a potentiometer (gate) at the front of the preamp. Don't believe me??? Turn your axe volume all the way down, now turn the amp all the way up. No sound??? Where's my 500 watts??? Your amp is all the way up (maximum) but no sound. The gate is closed on your guitar. Sometimes there is a volume control between amp stages. This is usually called "master". The amp manufacturer does not know what you may plug into that amp so it is designed for a range of signals (passive, active, etc.). So cranking your amp up to 500 watts (11) may not get 500 watts to the speakers. Maximum volume may be 1000w on a 500w amp but a very distorted 1000w. Do you want all that distortion??? I know some guitards that do.

^^^ To continue with what he's saying, a 500W amp absolutely dimed, while being fed a very very high input signal, may actually generate spikes up to 1000W in short bursts. Even under slightly less extreme circumstances, you may get it to put out a few spikes above 800W, meaning you do risk damaging the speakers.

This is especially true (and tricky) because the speakers' wattage rating is not equally valid for all frequencies; and the impedance of the speakers actually changes across different frequency ranges; and the amount of wattage the amp puts out is contingent on the impedance of the speaker load. So the reality is that the 500W and the 800W are both just generalizations and simplifications, not to be taken as literal hard facts.

In short: most of the time your signal will be way, way below 500W, because you are not slamming the input of the amp with a super-tall constant wave; but every so often, you risk sending in transient spikes that are higher than the speakers can safely handle. And the more often that happens, the more you risk blowing/burning the speakers. Cranking your amp to 11 increases that risk.

rbbrchkn · #9 10-06-2010, 10:24 PM

First of all, cab power ratings are almost entirely useless for telling you the amount of bass signal a given cab can handle. Your 800w cab can disperse 800w rms of power in the voice coils before the drivers melt. What really matters is the amount of low frequency excursion the drivers can handle before something goes wrong mechanically in the driver, and that limit can be reached at only a small fraction of the 800w rms rating.

Mechanical vs. thermal.

I trashed the drivers in a 1000w rms rated cab with a 200w amp before I understood that.

The other thing at work is power compression. You'll never get 800 watts of sound out of a cab at that rating because you get less out of your speakers for a given increase in power after a certain level because more and more power is turned into heat instead of sound.

As far as maxing the amp out is concerned, amps are designed so that you can use all of the power on tap, even if your signal is a bit weak. So all well-designed heads will max out before you hit "10" on the amp.

To get the most out of your setup that you can, just turn it up slowly until it starts to sound bad, mark that as "11", and then roll it back until it sounds good again, and mark that as "10" and don't go above it. If you're changing EQ settings or basses, repeat the process until you have a good feel for where your rig gives up the goods, but doesn't give up the ghost.

Tim Cole · #10 10-06-2010, 10:45 PM

That's the worse way to do things. I used to run 3400 watts into an eden 210xlt that was very loud, clean, and no issues. It's the square waves, and spikes that you get when pushing the engine wide open that kills things.

bongomania · #11 10-06-2010, 10:53 PM

Not square waves, that's an old wives' tale. But spikes over the speakers' excursion and thermal abilities, those are the killers.

Kwesi · #12 10-06-2010, 10:57 PM

Ok, that makes sense. My gut seems to be telling me to get a rack and go with power amp setup just because I sick of clipping my amp but I'll think about it more once I have my 4 ohm cab tomorrow.

MIJ-VI · #13 10-06-2010, 10:59 PM

Quote:

Originally Posted by Tim Cole

That's the worse way to do things. I used to run 3400 watts into an eden 210xlt that was very loud, clean, and no issues. It's the square waves, and spikes that you get when pushing the engine wide open that kills things.

billfitzmaurice · #14 10-07-2010, 06:46 AM

Quote:

Originally Posted by rbbrchkn

First of all, cab power ratings are almost entirely useless for telling you the amount of bass signal a given cab can handle. Your 800w cab can disperse 800w rms of power in the voice coils before the drivers melt. What really matters is the amount of low frequency excursion the drivers can handle before something goes wrong mechanically in the driver, and that limit can be reached at only a small fraction of the 800w rms rating.

+1. Spot on.

Quote:

It's the square waves, and spikes that you get when pushing the engine wide open that kills things

-1. Overpowering kills drivers. The shape of the waveform is immaterial.

Quote:

I used to run 3400 watts into an eden

If you had you would have cooked it. What you used to run was a safe output level from a 3400 watt amp. A more powerful amp makes it easier to do so, since you won't have amp clipping masking the sound of speaker clipping. But even if the amp is putting out a 100% clipped waveform that won't bother the speaker at all. If it did fuzztones and synths would equal instant speaker death.

Quote:

I sick of clipping my amp but I'll think about it more once I have my 4 ohm cab tomorrow.

The reason you're clipping your amp is that you can't get enough output without clipping it. Unless you have a very weak amp that's usually the result of inadequate speakers. You can only get so much out of a cab, no matter how much power you put into it or how much power it's rated for.