An ‘ukulele player must shop for an amp as well as a pickup to be able to “plug in”. This is something that you should take time on. Do your research. Try amps, talk to musicians, etc. In general (unless you are looking for a different tone) your best bet will be an acoustic guitar amplifier for you ‘ukulele. The good thing about looking for the perfect acoustic amp for an ‘ukulele is that there isn’t a huge selection to choose from. I can’t tell you what is best because we all have a different “sound in our heads” that we are trying to reproduce. The only way to find a great amp is to have an idea of the desired sound and start trying them. Here is a cross-section of an acoustic amplifier so you can be better informed in your search.
Amplifier – The amp itself is not the whole box, but just the circuit that lives in there. This circuit is what boosts the signal and determines the power of the whole unit. Just for the ease of things, call the whole setup an “amp“, but the word is really referring to the circuit that gives the big box its name.
Amp Head – This is a smaller box that does not contain speakers, just the amp circuit. You need a speaker cabinet to get any sound. So an amp head would be paired with a speaker cabinet for a two-piece setup.
Clip - Means there is too much input volume and it’s distorting the circuit. Sometimes an amp has a “clip” light. This shows you when the incoming signal is too hot and you should turn down.
Combo – An amp with the amp circuit and speakers all in one cabinet. Most acoustic amps are like this.
Effects – Sometimes amps come with onboard effects. Delay, reverb, and chorus are the most common. These are usually controlled by one or two knobs that change the parameters (time, feedback, depth, etc.).
EQ – Equalization controls the overall tone coming out of the amp. The EQ is usually controlled by three knobs: bass, mids, and treble. Other interfaces only include two knobs (bass and treble), one knob (bass on one side treble on the other), or sliders (with more specific frequencies). To boost a frequency range, turn the knob clockwise. To cut a frequency range, turn the knob counter-clockwise. Depending on what kind of sound you want, you probably want to start with all the knobs “flat” when dialing in your tone. Then from there you can tune things. A cut in the treble range can reduce the typical harshness of an ‘ukulele pickup. A cut in the mids or bass might help fight feedback.
Gain – The input gain or volume is controlled by a knob. The gain controls how much signal is being put through the amp circuit. Turning up the gain will boost the amp volume considerably, but it also makes the circuit more prone to distort (or at least put an edge on it). To get the most most tone and volume – “pop” – set the gain as high as you can without starting to clip.
Headroom – Is how much you can turn up the volume on the amp before it distorts. Headroom goes hand in hand with watts. More watts = more headroom. Since most of the time you will want a clean sound for your ‘ukulele, the more headroom you have the better. For example, you crank a 30 watt amp up all the way and it starts to bog down. If you were playing a 100 watt amp that loud you would have more headroom and the signal would cleaner.
Inputs – There are two common types of inputs that can be found on an acoustic amp, a ¼ inch phone jack and an XLR mic input. The ¼” is what you plug your ‘ukulele into (normally) and the XLR can be used for a mic or balanced signal (from a pre-amp). Sometimes you will be able to add audio from an outside source via an auxiliary input. This is for connecting your ipod or CD player so that you can play along.
Mic/line – Sometimes an input will be an XLR with a 1/4″ jack in the middle. This is known as a “mic/line channel”. You can use it for a mic or as a line in (‘ukulele). There is most likely a selector switch for changing the input levels.
Notch Filter (also Anti-Feedback) - This is a knob for reducing the low frequencies that cause the ‘ukulele to feed back. Turning this knob sweeps through a window of frequencies, each of which are cut down when selected. With this technology you can practically stand in front of the amp at full blast and not feed back.
Outputs – The main output would be the speaker, but sometimes you will want to send the signal elsewhere. Some common outputs are:
- Recording/line out for going straight into the PA or mixing board.
- Headphone out that allows you to plug in headphones without blowing them or your ears out.
- Effects loop for adding effects after the signal reaches the amp. This is said to sound better than having the effects in line on the way to the amp.
Phantom Power – It sounds like it should be a lot cooler, but phantom power is really very basic. If an amp has this feature, you can send a 48V current via an XLR cable to a phantom-power-capable piece of hardware (a microphone or DI box). This means no batteries or extra power cables.
Speaker – An amp can have any number of speakers in it. The speakers themselves are cones housed in a solid shell. The cone is attached to a big magnet that is turned on and off very quickly. The vibrating of the magnet moves the cone, and likewise the air, making sound waves. A big speaker is called a driver. The bigger diameter a speaker has the more defined the bass response. Small speakers are called tweeters. They produce lots of treble. Most of the time you will see a driver and tweeter combination to get a more balanced sound.
Speaker Cabinet – The speaker cabinet is a separate wooden box that holds the speaker(s). On acoustic amps, usually the amp and cabinet are all one. If you have just an amp head you will need a speaker cabinet to make noise. The size of these speaker cabinets vary, but the most well known size is the Marshall half stack with 4 12 in. speakers (think Jimi).
Stack – Rare for acoustic amps (I’ve never seen one), but worth explaining nonetheless. A stack is the amp head and cabinet together. Think really Jimi Hendrix.
Tube vs. Solid State – A “tube amp” is an amp that use tubes (clever) in its circuit to boost the signal. Tube amps fatten up the signal more than solid state – they are also more expensive and heavy. A solid state amp uses transistors to boost the signal for a more clean sound. Most acoustic amps on the market are solid state because with solid state technology, clean gain is easier to come by.
Watts – How many watts an amp is rated for determines its power and loudness. A 60 watt amp is going to be louder than a 30 watt amp. Around 100 watts is the power that is needed to play in a full band. Much beyond that and a PA system is going to make more sense. With that in mind, if you set up a 100 watt acoustic amp next to a 100 watt electric amp, woe to the ‘ukulele player.
There is no right answer when searching for the perfect amp for an ‘ukulele. Talk to as many people as possible, learn as much as you can, and try all the amps in the music store.
Some of the most respected brands are: Fishman, Roland, LR Baggs, AER, SWR, and Fender.
The nicest amp I have played into is the Roland AC-90. I use it with my Kamaka tenor with a MISI Acoustic Trio active pickup (previously a K&K Big Spot SBT passive pickup. They both sounded great through it, though the MISI is a better pickup). The AC-90 is pristine clear, loud, and doesn’t seem to want to feedback much. The amp has two channels, one for your instrument and one for a mic or second instrument, delay and reverb, chorus, notch filter, a mute switch, etc. Read my full review of the Roland AC-90.
A PA system is also a viable option for amplifying your ‘ukulele. Since most players are just looking for a clean volume boost, a PA could be the best bet for you. Make sure your pickup or pickup/preamp combo is up to snuff before you commit to this option. Because the PA is just made to make the signal louder, that’s just what it does. The signal the PA receives is what get amplified. So you’ve got to make sure that the signal that hits the front of the PA is the best it can be – they aren’t at all forgiving.
Here are some more in depth resources about acoustic guitar amps and amplification. (these go into details on pickups as well)