Can You Use a Guitar Amp for Bass?

In a perfect world, every bassist would have access to their own amp at all times. However, pretty much every experienced player has encountered a situation where their own rig simply wasn't available. If you're ever jamming with friends or playing a gig and your amp goes down, can you use a guitar amp for bass?

There are also situations where there are simply no available bass amps around. The bulky, heavy nature of many larger bass amps also causes bass players to try plugging into someone else's amp to save themselves the hassle of lugging their bass amp around.

Is it safe to use a guitar amp to power your bass? The answer hinges on a few different factors; your individual circumstances may lead to a different result. This article explains what you need to know about using a guitar amp for your bass, and explains what you can do to keep it as safe as possible in every situation.

What Differentiates Guitar and Bass Amps?

Before discussing when it is and isn't safe to plug your bass into a guitar amp, it's helpful to learn a bit more about what actually separates guitar amps from bass amps under the hood. Though they may look very similar — large, heavy boxes covered with black or silver grills — guitar and bass amps have a few key distinctions that can lead to massive differences in tone and safety.

The most obvious difference between guitar and bass amps lies in the speaker. Depending on the size of the amp, guitar amps generally feature a speaker anywhere from 8″ to 12″ in diameter. These speakers all have their own EQ signatures — in plain English, this means they're all tailored to provide a slightly different sound, with varying emphasis on the treble frequencies, mids, and bass ranges.

The smaller speaker size also means that guitar amps are simply capable of a different range of frequencies than bass amps. An open E note, the lowest frequency produced by a guitar in standard tuning, sounds at around 82 Hz — most guitar speakers are optimized for ranges down to 80 Hz to accommodate this low end.

The highest fundamental note most guitars can produce lies just shy of 1,200 Hz (a note at the 22nd fret on the high E string). However, many guitars can often produce sounds at frequencies up to 5,000 Hz, thanks to overtones and other higher resonating sounds. Most speakers in guitar amplifiers, accordingly, top out around the 5,000 – 5,500 Hz range.

Bass amps, meanwhile, specialize in much lower frequencies and put less effort into higher sounds. Larger speakers provide more low-end output power. Some bass amplifiers will use 10″ speakers, but 15″ speakers are the most common size and even 18″ speakers aren't unheard of. Bass speakers carry their own EQ signatures as well, which tend to favor lower, louder sounds over precise and clear high notes.

To effectively amplify a bass and provide headroom before the signal begins to distort, many speakers on bass amps can accommodate frequencies as low as 20 or 30 Hz. The top end of the range lies around 2,000 Hz on most bass amps, with some going even lower.

Safety Concerns

Safety is clearly the largest concern when attempting to plug a bass into a guitar amplifier. Will the lower frequencies fry the amplifier circuit? Will the speaker give out under the excess load? The answer depends on a couple key factors.

Your playing volume will largely determine whether or not it's safe to run your bass through a guitar amplifier. At low volumes, you should be able to get away with plugging into a mid-sized guitar amp, especially if you focus on the higher strings and stay away from the lowest available notes.

Keeping the volume low will reduce the stress on the speaker and prevent it from giving out as you play. Reducing the bass frequencies by rolling down the bass knob on your instrument can also help guard against speaker damage.

Amplifier size will also play a role in accommodating your bass. A small solid-state practice amp with a tiny speaker — say, a Fender Champion 20 — simply lacks the size and speaker diameter to handle any sort of bass. Even at bedroom rehearsal volumes, plugging a bass into amps of that caliber is flirting with disaster.

The larger the guitar amp you use; however, the greater the chances are that you can play it safely. Massive 100-watt tube amp heads and large combos with one or multiple 12″ speakers will be able to handle a bass for longer periods of time. As an added bonus, these amps can also amplify the bass at higher volumes without giving out.

Very few guitar amps can handle a bass at volumes loud enough for jam sessions or live gigs, though. The safest possible strategy is to only play your bass through a guitar amp when practicing alone, and to keep the volume as low as possible. If you can, though, it may just be better to practice unplugged if a bass amp is unavailable for whatever reason.

Pre-amps in guitar and bass amplifiers are similar enough that you're unlikely to cause damage to them by playing a bass through a guitar amp. Though it may technically be safe; however, lower-grade pre-amps can cause all sorts of problems with your tone with a bass plugged in.

Beyond immediate destruction, using a guitar amplifier for bass is likely to cause long-term damage to internal components. Running the bass through the amplifier puts extra stress on the pre-amp and speaker alike; over time this damage can snowball even if you keep the volume down and only play sparingly.

Bass playing also incorporates many more quick changes in volume and sound than most guitar genres do. Techniques like slapping and popping can be harmful to guitar speakers, even if the rest of your notes remain at a low volume. The smaller guitar speaker simply can't handle the fluctuations the same way bass amplifier speakers can. If you're not careful, a poorly timed slap or pop can be the quickest way to fry your speaker entirely.

You should always try to avoid using a guitar amp for bass unless you're okay with accidentally destroying that amp. Most of the time, you can get away with practice-level volume if you take it easy on the low strings and consciously avoid changing volume too quickly.

However, it's impossible to predict exactly how a certain amplifier might react to a specific bass in every situation, and using a guitar amp for your bass is flirting with disaster. The margin for error increases as the guitar amp grows larger and more powerful — but you should never use a guitar amp as your everyday bass amp.

Tone Differences

Even if you manage to find a guitar amp that can handle a bass without blowing up the speaker, your tone will still be adversely affected by the change. The drastic differences in components between guitar and bass amps mean that they're optimized to put out fundamentally different tones and won't sound as good with the wrong instrument plugged in.

Guitar amps simply can't provide the same low-end sound that bass amps do. That fact is responsible for most of the speaker damage bass players cause to guitar amps — but even when you play at safe volumes, the difference will still affect your tone.

Bass players running through guitar amplifiers will find that their sound lacks the usual booming, punchy low end. In fact, guitar amps will often turn the bottom end of a bass into a sludgy, indistinct wash of sound without any definition or impact.

Pre-amp stages in many guitar amplifiers may also harm your tone with a bass. Certain amp models can handle the input better than others, but some pre-amps will distort when faced with the rush of low-end frequencies. This becomes a problem as you turn up with a guitar amp — you'll nearly always find that you have less headroom than on a traditional bass amp.

On the plus side, some guitar amplifiers will actually provide a clearer, fuller high-end than many bass amps. The highest notes that bass amps can put out actually land right in the frequency wheelhouse of many guitar amplifiers.

Occasionally, professional bass players will split their signal between a bass amp and a guitar amp, filtering the low end to the bass amplifier (which is better equipped to deliver traditional punch and power) and sending the high end to the guitar amp for added clarity and precision. This setup is expensive, and it doesn't make much practical sense unless you frequently play high up on the neck.

Sub-optimal tone is simply a part of the package when you play bass through a guitar amp. However, if you hear a sputtering or “farting” sound coming from the speaker, put the bass down and stop playing. That noise signals the speaker is beginning to give out; pushing it any harder could ruin it altogether.

Summary

So, is it alright to play your bass through a guitar amp? The short answer is “maybe.” If you stay at low volumes for practice and play through a guitar amp with a decently sized speaker, you should be okay. However, no bassist should use a guitar amplifier as a long-term substitute for a proper bass amp.

If you've just bought a bass and want to check out some corresponding amps, take a look at our list of the best bass amplifiers for some ideas in every price range.

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