Here's How Many Watts A Guitar Amp Uses (the real answer)

Here’s How Many Watts A Guitar Amp Uses (the real answer)

The amount of watts a guitar amp uses is dependent on a number of factors but the average amplifier uses anywhere between 100 to 200 watts every hour it is in use. 

That’s around the same amount as the average refrigerator, a bit more than a ceiling light and around 10 times less than an air conditioner unit. 

There’s more to it than that though, so keep reading to find out the real answer to the question: how many watts does a guitar amp use?

Amplifiers Electricity Usage

The amount of electricity your amp uses is calculated by multiplying its wattage by the amount of time it’s running and the cost of electricity and taking into account the volume level the amp is set at. But with so many amps available, all with different features, it can be a complicated process to work it all out exactly.

As we said earlier, the average amplifier uses anywhere between 100 to 200 watts every hour it’s in use. However, many amps use far less and many use far more, that’s why this is an average amount. 

The amount of electricity an amplifier uses depends on a number of factors. These factors include;

  • The power consumption of the amp
  • The volume it’s used at
  • Whether it’s solid state or valve
  • How long it’s used for

“What do you mean by solid state or valve?”

Solid state and valve amps work in different ways to achieve the same result. They have different components which use power in different ways. Which means they’re power consumption is varied too. 

How The Volume Makes A Difference

To achieve a more dynamic sound, the amp has to draw more power. This means no two identical amps are using the same amount of power at the same time, unless they are set at exactly the same volume level.

SEE ALSO: Can You Play Two Guitars Through One Amp?

The Fuse Value Is A Good Indicator For Electrical Consumption 

If you look on the back of any amplifier, you’ll find the fuse value stated on a label somewhere. The fuse value is a good way to see how much electricity the amp will use. Most electrical appliances are fused at twice the rate they usually run at for safety reasons. The chart below shows the fuse value for some of the more common amps in relation to their wattage.

AmplifierWattageFuse Value (Amps)
BOSS Katana-50470.7
Orange Crush 352402
Marshall2402
Fender Reverb3002.5
Line 6 Spider Jam6005

From the above table it’s clear to see that there is a direct relationship between the fuse value and the amount of electricity used. A good way of predicting how much electricity an amp uses is by seeing how high its fuse value is. However, there are other factors at play here.

As we said earlier the volume the amp is set at and the timespan of usage will affect the electricity usage in a big way. Using the amp on our list with the largest fuse value, the Spider Jam from Line 6, for a short amount of time and at low volume will use a small amount of power.

Alternatively, at the other end of the spectrum, using  the BOSS Katana-50 for many hours at its highest volume would soon start to use far more power.

Marshall guitar amplifier

Does A 100 Watt Amp Use 100 Watts Of Power?

This is where things get confusing, or interesting depending on your point of view. It might seem logical to expect a 100 watt amp to use 100 watts of power. However, that 100 watts is the amount of power that particular amp can produce. 

It’s the amount of power that an amp can send to the speakers.

The amount of electricity it draws from the mains supply to produce that 100 watts is another story. In most cases, the amount of electricity an amp takes to produce its full power is significantly more than the figure stated on the amp itself.

However, if the amp is used at low volume, it uses less electricity than it would at full volume. 

The main reason that an amp uses more power than it can produce is loss of heat. 

The Difference Between Class A And Class AB Amps

We’re starting to get a little technical here now, but we’ll try to keep it as simple as possible. A good way of determining how much power an amp uses is by comparing the two amp types. There are two main types of amps which are Class A amps and Class AB amps.

They’re both extremely popular but they both use different components that make a difference to the amount of power they consume. Basically, Class A amps use far more power due to heat loss than Class AB amps. This is because of the internal processes which mean that Class A amps run power continuously whereas Class AB amps cut the power when it’s not being used.

There’s far more to it than that but we’re here to find out how many watts a guitar amp uses, not  studying for a degree in electronics. Most Fender and Marshall amps are Class AB amps  whereas Vox amps are Class A amps.

Here’s a short overview of both types for your information.

Class A Amps

Compared to Class AB amps, Class A amps:

  • Use greater amounts of electricity
  • Constantly strain the tubes
  • Have shorter tube life

However they also

  • Produce louder volumes
  • Instant signal amplification

Class AB Amps

  • Use less electricity
  • Put less demand on the transformer
  • Have clearer low end sounds
  • Have longer lasting tubes

But they are also

  • Less responsive

How To Calculate The Exact Amount Of Electricity Your Amp Uses

We’ve explained all of the whys and wherefores, so let’s actually look at an amp and work out exactly how much it costs to run. 

Let’s take a 40 watt amp that’s played for an average of one hour a day, every day. For simplicity let’s assume a 30 day month and see what we get.

So let’s multiply 40 watts by one hour by 30 days which looks like this: 40x1x30=1200. So that’s 1200 watts per month or 1.2 kWh. 

In the UK the average price per unit of electricity is 34p which means our cost for using our amp for one hour per day every day for a month is 41p which is calculated as follows: 34×1.2=40.8

Which we’ve rounded up to the nearest penny which makes it 41p. However, as we now know an amp uses roughly twice as much power as it outputs – we should reckon on using 82p per month in reality.

To find the exact figure you’d need to consider all the energy consumed by the amp which can vary.  Guitar amps consume power to light LEDS, power tubes, fuses etc. So to find the exact figure down to the last penny you would need to use an ammeter (amperemeter). 

We wouldn’t recommend using an ammeter unless you are competent as you could do more damage than good. 

How Much Power Does A Guitar Amp Use?

If you’re worried about how much power your guitar amp is using, or more likely if you have been getting an ear-bashing by someone else in your home about the cost of running your amp, just show them the above figures and that should appease their worries.

SEE ALSO: The Best Apps To Learn Guitar In 2023

Frequently Asked Questions

How much power does a 100 watt guitar amp use?

A 100 watt tube amp will use 200 watts at full power whereas a 100 watt solid state amp will use 160 watts at full power.

Is 20 watts enough for a guitar amp?

20 watts is enough for a solid state practice amp, if you were to use a tube amp you would only need a 10 watt amp.

Is 50 watts enough to gig?

A 50 watt solid state amp is enough for a small gig but it might struggle to be heard over an enthusiastic drummer, and would definitely not be powerful enough to be heard at a large gig.

Do higher wattage amps sound better?

Higher powered amps will sound clearer and louder than smaller wattage amps. However to hear a perceptible difference, you would need to use twice the wattage.

Disclosure: We are a professional review site that receives compensation from the companies whose products we review.

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