Plugging in an acoustic-electric: how to choose the right amp for your plugged-in sound

I remember the first time I plugged my old dreadnought into a borrowed guitar amp at a folk night. The thing honked and squealed like a barn door in a gale. The body resonance turned into a wall of feedback, and any subtlety in my fingerpicking got buried under a layer of boxy midrange that suited a Telecaster but absolutely did not suit a spruce top. I learned something that night: an amp built for electric guitars is not automatically a friend to an acoustic-electric, and understanding why makes choosing the right one a lot easier.

Why acoustic-electrics ask different things of an amp

An acoustic guitar's natural voice is wide, open and full of transients — the crack of a nail on a string, the thump of a thumb landing on the low E, the air moving inside the body. Undersaddle pickups and soundhole pickups capture some of that, but what they send to an amp is a signal with a very different character to a humbucker or a single coil. There is far more low-mid content, more attack sensitivity, and a much greater tendency to feed back at volume.

A standard electric guitar amp is voiced to complement magnetic pickups. The speaker is often designed to roll off the very top end and add a pleasing, coloured warmth. That colouration is the whole point when you're playing electric. But run a piezo or an undersaddle pickup through the same speaker and that colouration tends to fight the natural tone of the instrument rather than flatter it.

The case for a dedicated acoustic amp

Acoustic amplifiers — sometimes called acoustic instrument amps — are built around a flat or near-flat frequency response. They aim to reproduce what the pickup gives them as faithfully as possible, trusting that the instrument itself is providing the character. They typically use full-range speakers, often a tweeter paired with a woofer, and their preamp sections have EQ shapes suited to the broader frequency content of acoustic instruments. Many include a notch filter or phase switch specifically to combat feedback, which is one of the most persistent problems with acoustic-electrics in live settings.

If you play plugged-in acoustic regularly — at open mics, in small venues, at house concerts — a dedicated acoustic amp is worth serious consideration. They are not glamorous pieces of gear and they rarely come up in conversations about tone, but they do one job very well.

When an electric guitar amp can work

That said, plenty of players run acoustic-electrics through electric guitar amps and find something they like in the results. A clean, low-wattage amp with a relatively neutral voicing — something that does not aggressively push the midrange — can work well at modest volumes. The key word there is clean. Any breakup in the preamp or power section tends to sound unpleasant with a piezo signal; it thickens and smears in a way that usually flatters an electric but muddies an acoustic.

If you are going down this route, a small, low-wattage amp with a good clean headroom is far more useful than a higher-powered amp you have to run at a whisper. You also want to be careful with the amp's EQ — cutting the bass and some of the low mids, and easing back on any presence boost, tends to get you to a more usable starting point. For more on what wattage actually means in practice, our explainer on the best practice amps for home and learning covers the relationship between power and usable volume in plain terms.

Modelling amps and acoustic simulation

This is one area where modelling technology has genuinely moved things forward for acoustic players. Several modern modelling amps include acoustic body simulations — essentially impulse responses or voicings designed to make a magnetic or piezo pickup sound more like a miked acoustic guitar. The results vary, but at their best they can be surprisingly convincing, and the flat, full-range output of many modelling amps means the underlying signal is being handled honestly before any simulation is applied.

The Yamaha THR10II (check price) is a good example of a modelling amp that has a dedicated acoustic mode alongside its electric voicings — useful if you switch between both instruments. The clean channels on amps like the Boss Katana-50 MkII (check price) are wide and neutral enough to handle an acoustic-electric without doing too much damage to the sound, particularly at the lower end of the volume range.

Feedback: the thing nobody warns you about

Feedback from an acoustic-electric is different from the controlled, musical feedback an electric player might dial in deliberately. It builds fast, sits in a narrow frequency band — often somewhere around 200 to 400 Hz — and once it starts, it is very difficult to control just by moving away from the amp. The shape of the guitar body acts like a resonant chamber that amplifies the problem.

There are a few practical ways to manage it: keep the amp at an angle to the guitar rather than directly behind you, use the phase switch if your amp or pickup preamp has one, and consider a soundhole plug, which reduces the body's resonance at the cost of a slight change in tone. Some players run a parametric EQ or a feedback-hunting pedal in the signal chain — modest solutions, but they work. The discipline of setting your volume thoughtfully matters too. Acoustic amps tend to handle higher volumes better than electric amps in this respect, simply because their response is more controlled in those problematic frequencies.

A few things to listen for when trying amps

When you take your acoustic-electric to a shop to try amps — and it is worth taking your own instrument, not relying on whatever is on the wall — listen for honk in the low mids, which is the most common problem. Listen for how the amp handles the transients of your picking; a good amp should let you hear the difference between a gentle brush and a more assertive stroke. And check the feedback threshold by standing close to the amp and letting a chord sustain. You will find that threshold quickly, and knowing where it sits tells you a lot about how the amp will behave in a real performance setting.

If you are still building out your acoustic setup more generally, our guide to choosing your first acoustic guitar is a good place to start thinking about how the instrument itself shapes what you need from amplification further down the line. And if you are pairing your acoustic amp with any outboard reverb or effects, take a look at our best reverb pedals guide — a little room reverb can do a great deal to open up a plugged-in acoustic sound in a way that suits the instrument's natural character.

The right amp for an acoustic-electric is the one that gets out of the way and lets the wood do the talking. That is a different brief to most of what electric guitarists ask of their gear, but once you hear it working well, it is hard to go back to fighting an amp that was never meant for the job.