ʻUkulele Preamps: The Impedance, Gain, and EQ Fix-It Box

If you’re lucky, plugging straight into an amp will make your ʻukulele sound great.

But more often than not, you’ll be victim to the quirks and character of your gear. This results in a less-than-perfect sound.

The Gold In, Gold Out Rule

If you start with a great sounding pickup, there will be much less to fix along the way. It’s way easier to tweak a sound that’s already 90% of the way there than to try and manipulate a crappy sound into greatness.

Be sure to do some homework on pickups and keep your expectations realistic if working with sub-par equipment. If your starting sound is garbage, you’re better off spending your money on a new pickup, not a preamp.

What Does a Preamp Do?

alix preampA preamp, in a limited sense, is a circuit that boosts and matches your signal with the input of an amp or PA. In most applications, an acoustic preamp comes with several tools to help you tune up your sound.

It Balances Impedance

If your pickup outputs a signal that is not what the input (amp/mixer) is expecting, you’ll have an impedance mismatch.

This can cause a host of problems that are usually fixed with a preamp.

Impedance is the resistance of an electrical circuit, usually measured in ohms – shown as: Ω.

A mixer or amp usually expects a low-ish impedance source at its input. For instance, an electric guitar has around a 1-2kΩ impedance. A microphone is even less, at 150-600Ω.

Contrast this to a typical passive ʻukulele pickup which provides somewhere around 1MΩ (that’s one million ohms)! The mixer isn’t able to handle such a large amount of resistance and this results in “loading” the pickup circuit.

When there’s an impedance mismatch like this, a handful of bad things happen, such as: low volume, loss of low-end resulting in a thin, “quacky” tone, and noise.

A preamp will convert the pickup impedance to something that the mixer can process better.

This is vital if your pickup is passive. An active pickup will already have a more reasonable impedance (my LR Baggs Five-0 is 3.6kΩ), but can still benefit from the other features a preamp usually provides.

It Boosts the Signal

Impedance mismatching aside, a pickup often produces a weak signal. This requires cranking the knobs on a mixer or amp way up to get a reasonable volume. Pushing the controls like this doesn’t create the best possible sound.

Fortunately, a preamp has a gain control. This increases the input volume – or circuit sensitivity – which ups the output many times over.

Extra gain is great, but if you let too much signal into the circuit it will overload, causing what’s known as “clipping.” Clipping is when the top of the waveform is cut off, and it manifests as distortion.

Depending on the preamp, you want to set the gain control so that on your very hardest strumming, the signal clips slightly. This gives you the most possible boost with a reasonable amount of headroom left over.

It (Usually) Provides EQ Control

An incredibly useful feature most preamps have these days is an EQ section. It’s possible that your pickup outputs a perfect sound, but not likely, which is why I always insist on EQ controls in a preamp.

Equalization sculpts the tone of your signal. It allows you to boost or cut certain frequencies.

I wrote more about EQ on my page about ʻukulele pickups:

Getting the most out of your pickup (scroll down to “Tweak the EQ”)

Do I Need a Preamp?

It depends on your situation and the impedance of your pickup and amp or PA.

If you have an active pickup, you can usually run without a preamp. However, you might find the extra control a preamp gives you in volume and EQ is worth the hassle and money.

If you have a passive piezo pickup, the short answer is: YES, you need a preamp. These pickups can sound great, but they need an optimized environment to really shine.

That said, there are times when you don’t need a preamp for a passive pickup. Like when the input is high-impedance! (Actually, this is probably the only time you’ll get away with it.)

A high-impedance input can come in the form of an acoustic amp (like the Fishman Loudbox Mini) or as a high-grade, piezo-intended stage direct box. This type of direct box is few and far between so don’t count on them at a gig unless you’re Jake Shimabukuro and you ask specifically for it.

Preamps Options

Preamps come in many flavors and the options can be overwhelming.

If at all possible, try your ʻukulele with any preamp you might want to buy. The way your pickup interacts with the circuit of the preamp is likely different than mine.

For example, here’s a shootout I did with my friend, Tobias Elof, of our preamps of choice at the time (Lehle Acouswitch Junior and LR Baggs Venue DI).

It’s subtle, but interesting to hear the difference in sound between two pedals that do almost the exact same thing. I’d expect this variety in signal coloration from any two preamps.

Preamps I Like

I’ve been plugging my ʻukulele in and performing onstage for over a decade. For the most part, I’ve “been there, done that” and have found what works best for me over the years. That’s exactly what I’ll recommend to you. It’s not that other preamps are BAD, I just haven’t used them or choose not to.

Personally, I require a parametric EQ section in any preamp I use. It’s the hands-down best way to fine-tune the sound of your pickup and make adjustments depending on the room. This is an EQ that lets you precisely select which frequency to boost or cut (other EQs have fixed frequencies – a less precise approach).

q\strip diCurrently, my favorite out of the six or so preamps I’ve tried is the Tech 21 Q\Strip.

It’s not an acoustic preamp, per se, but provides the key requirements and great sound. The input is rated at 4.7MΩ, which is sufficient for most passive pickups, there’s ample amounts of volume, a DI output, and two parametric EQ bands – along with high and low EQ controls.

The industry standard for middle-of-the-road preamps is the Para DI by LR Baggs. This is the easiest unit to recommend to anybody since it’s tried and true.

If you want something more fancy, I like the LR Baggs Venue DI. Though the tuner kind of sucks and, for the space it takes up, I’d probably just get the Para DI.

Direct Input

Many preamps (including the Venue and Q\Strip) have an XLR output that sends a line level signal. This is commonly known as a DI – or direct input/injection. By utilizing a DI output you can provide a strong signal right to the mixing board and not worry about signal degradation along the cable.

This can be great if you play through a PA a lot. It reduces the need for an extra DI box. If you play mainly through an amp, you might want – or need – to use a 1/4″ cable anyways and the DI feature will be wasted.

The sound that is produced by the preamp will be basically identical whether using XLR or 1/4″. The only difference will be the level of the signal.

Other Options

Everybody has their own needs and preferences with gear. As such, there are many options suitable for an ʻukulele preamp. However, finding them is difficult. They seem to get buried under the hype of electric guitar pedals.

I figure it can’t hurt to put together as comprehensive a list as possible of acoustic instrument preamps. “EQ” assumed to be fixed-band based (parametric shown as “para-EQ”). Possibly better options for uke in bold.

  • Audio Sprockets Tonedexter – ($399) High/low EQ, notch, Wavemap for creating impulse responses by plugging in a mic
  • BBE Acoustimax – ($149) Para-EQ, mute, notch, phase, sonic maximizer, FX loop, DI
  • Behringer ADI21 V-Tone – ($29) Para-EQ, DI
  • Boss AD-2 – ($99) Ambience, notch, acoustic resonance, mute
  • Boss AD-10 – ($334) Two-inputs, Para-EQ, compression, ambience, delay/chorus, anti-feedback, acoustic resonance, boost, tuner, FX loop, DI
  • Fishman Aura Spectrum DI – ($349) EQ, compression, Aura imaging, tuner, phase, FX loop, anti-feedback, DI
  • Fishman ToneDEQ – ($299) Reverb, delay, chorus, flanger, tremolo, phase, compression, EQ, boost footswitch, DI
  • Fishman Platinum Pro EQ/DI – ($299) Para-EQ, low-cut, compression, tuner, boost, notch, phase, FX loop, DI
  • Fishman Platinum Stage EQ/DI – ($149) Para-EQ, boost, phase, low-cut, DI
  • GMF Al1 – ($99) High/low EQ, phase, DI
  • Grace Design BiX – ($295) High/low EQ, boost, mute, DI
  • Grace Design ALiX – ($695) Para-EQ, low-cut, boost, mute, phase, DI
  • Grace Design Felix – ($1075) Two-channels, Para-EQ, low-cut, mute, boost, phase, FX loop, 48v phantom power, DI (2)
  • JHS The Clover – ($199) EQ, low-cut, DI
  • K&K Pure – ($99) EQ
  • K&K Pure XLR – ($177) EQ, phase, DI
  • Lehle Acouswitch IQ DI – ($599) Two-inputs, para-EQ, mute, boost, FX loop, DI
  • LR Baggs Gigpro – ($99) High/low EQ, phase, belt clip
  • LR Baggs Mixpro – ($169) Two-inputs, high/low EQ, 48v phantom power
  • LR Baggs Venue DI – ($299) Tuner, para-EQ, boost, notch, phase, FX loop, DI
  • LR Baggs Session DI – ($249) Notch, saturation, compression EQ, low-cut, mute switch, phase , DI
  • LR Baggs Para DI – ($189) Para-EQ, notch, FX loop, phase, DI
  • Mesa/Boogie Rosette – ($379) Para-EQ, low-cut, notch, boost, mute, phase, FX loop, DI
  • NUX Stageman Floor – ($149) 3-band EQ, notch, chorus, reverb, FX loop, DI, headphone out
  • Orange Valve Pre – ($899) Two-channels, para-EQ, reverb, phase, mute, 48v phantom power, FX loop, DI
  • Pigtronix Bob Weir’s Real Deal – ($279) Two-input, crossover, phase, anti-feedback, 48v phantom
  • Radial AC Driver – ($149) Two-inputs, low-cut, notch, phase, mute, DI
  • Radial Tonebone PZ-Deluxe ($249) Para-EQ, low-cut, phase, mute, boost, DI
  • Radial Tonebone PZ-Pre – ($299) Para-EQ, low-cut, notch, phase, boost, mute, FX loop, DI
  • Tech 21 Q\Strip – ($249) Para-EQ, high-cut, low-cut, DI
  • Trace Elliot Transit A – ($299) Reverb, delay, chorus, boost, tuner, phase, notch, EQ, DI
  • Zoom AC-2 – ($199) EQ, boost, tuner, reverb, anti-feedback, DI

If one of those doesn’t meet your needs you’re in serious trouble!

By Brad Bordessa

I’m an ‘ukulele artist from Honoka’a, Hawai’i, where I run this site from a little plantation house in the jungle. I’ve taught workshops internationally, made Herb Ohta Jr. laugh until he cried, and once borrowed a uke to jam with HAPA onstage in my boardshorts. More about me

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