Audio Sprockets

ToneDexter II Tone-Correcting Preamp

(6 reviews) Write a Review

We ship worldwide! (Read this)

To Continental US (Lower 48)
  • ToneDexter II Tone-Correcting Preamp - top angle view
  • ToneDexter II Tone-Correcting Preamp - controls closeup
  • ToneDexter II Tone-Correcting Preamp - infographic
  • ToneDexter II Tone-Correcting Preamp -rear panel
  • ToneDexter II Tone-Correcting Preamp -connectivity info
Our Low Price: $599.00

Price shown may adjust with options selected below (if applicable)


Tonedexter II is new and improved!

The original Tonedexter was already great - but the newly released model (we got our first shipment in December of 2023) has more powerful features, a new color screen, and improvements to ease of use. However the ability to plug your pickup into ToneDexter II and the output to the PA or your acoustic instrument amp, select a WaveMap, to make your live pickup sound match your studio mic, remains the same.


With ToneDexter, getting "mic'd up tone" in your live performances is as easy as...

Copy and Paste

At first blush, the ToneDexter looks like a pretty standard preamplifier for acoustic instruments. While most preamps offer helpful features like EQ, high-impedance buffering inputs, and notch filters (so does ToneDexter) - ToneDexter is a lot more. This baby has got some serious DSP technology under the hood.

Here is what the ToneDexter does, simply put, and I've put it right at the top of the page to make sure you don't miss it:

  1. The ToneDexter compares the acoustic sound of your bass (using a microphone) to the sound coming from your pickup.
  2. It then creates a WaveMap; a sonic signature, of sorts, which corrects the sound of your pickup, making it sound much more like the microphone signal.
  3. The preamp stores this WaveMap (and up to 21 others), allowing you to recreate that acoustic tone in a live situation, using just your pickup.

So you're essentially copying the tone from a microphone, and pasting it to your pickup.

The way Audio Sprockets explains it: ToneDexter is an innovative professional grade preamp that improves the sound of an acoustic instrument pickup. It can learn the difference between how an instrument sounds through a microphone and how it sounds through its pickup. Using patented WaveMap® technology, it corrects the pickup so that it sounds like the mic.

Includes our exclusive Gollihur Music tipsheet to get the most out of your purchaseNow, this thing sounds "tech-y" - and if you're not a "gear nerd" like me, that might scare you a bit. But it's actually pretty easy to wrap your mind around.

To make it more clear: The problem with pickups, generally speaking, is that they don't sound like a mic. Usually, they have a more "direct" tone that lacks the open "airiness" that a microphone has. The reason is fairly simple: the microphone actually gets the sound out of the air - like your ears do - while most pickups provide their sound from the wood vibrations created by the instrument.

So, when you first get your ToneDexter, you do a one-time "training session" with both a mic and the pickup plugged in at the same time. While you play during this training session, ToneDexter listens to both signals simultaneously and "learns" the differences between how each of them "translates" the vibrations into sound. ToneDexter figures out how to correct for the pickup’s deficiencies, and restores the missing "body tone" to the pickup signal. It's basically bringing back that realism that the microphone "hears" but a vibration-sensing pickup usually doesn't. It also adjusts for the best gain levels for optimal tone.

ToneDexter then allows you to save the resulting WaveMap, with a simple press of a button, in one of 22 available preset locations.

The next time you play live, you leave the mic at home, and just use your pickup, and the ToneDexter's WaveMap applies those corrections to your pickup's signal, making it sound a lot more like the microphone. So you get much more realistic acoustic sound, while still using a far more convenient (and generally much less complicated) pickup.

The training process is not difficult at all. All you need:

  • a quiet room
  • your bass and pickup
  • a good quality microphone (small diaphragm condensers work well)
  • a set of headphones is also very helpful, as you can monitor the process if you have headphones on.

You plug both the mic and the pickup in, and just follow the prompts to start the training process. Mostly, your job is to just noodle around on the bass - the preamp does all the heavy lifting. You don't even have to play anything in particular - just do some scales, or some of your favorite basslines. And you can do it several times, as there are multiple locations to save the WaveMaps you create. So if you have several basses and/or pickups, you can save WaveMaps specific to each instrument.

So, yeah -- too good to be true, right? I hear you. We had to try this thing for ourselves before we'd buy into the hype; so I got a unit on loan from Audio Sprockets about a month before we committed to sell the unit. Even with our half-hearted first attempt, using a so-so mic and no headphones, the unit gave us noticeably better sound with the pickup. When we later put more effort into the process (grabbed a good set of phones and a nice Oktava mic from my studio) the results were even better.

This thing is legit.

What pickup works best? In talking to the folks at Audio Sprockets, and experimenting here at Gollihur HQ, we've found that bridge wing pickups are among the better choices - specifically, the Kremona (KNA) DB-1 worked best with the ToneDexter, and the K&K Bass Max and Schatten Design RB1 worked pretty well too. The Fishman Full Circle and David Gage Realist Lifeline also work nicely, as they have mostly full-range sound. Pickups that don't necessarily reproduce all of the tonal spectrum - like the David Gage Realist, which can be somewhat "dark" - don't work so well. And those close to the strings - like the K&K Double Big Twin or Fishman BP-100 - can have some difficulty getting as natural a tone, because they tend to emphasize string detail and require excessive "correction" to sound more "mic-like."

So, is this a preamp or a modeler? You could call the ToneDexter's process "digital modeling" - and I suppose it's a reasonably accurate description of what it's doing. But their patented process is proprietary (say THAT five times fast!), and the modeling it does is of your own bass (rather than some generic "upright bass" sound that the maker of the electric bass preamp threw in at the last moment to give it more marketing appeal). So it legitimately captures YOUR sound. From YOUR bass. And gives it to you live without hassle.

So cool.

Features New to ToneDexter II

If you were familiar with the original ToneDexter, you'll find a ton of new improvements. A brand new COLOR screen with context-sensitive knobs replaces the old display - the new screen provides MUCH better guidance and information for the use of the preamp. The old one used an SD Card for transferring/saving patches and maps; the new one has a standard USB port. And whereas the original model had different firmware versions for different instruments, the new ToneDexter 2 has just one firmware to rule them all! Everything has been updated, improved, and made more useful!

Here's a specific list of the changes/updates/improvements:

  • Color screen, context sensitive controls and labels
  • All parameters can be stored and fully recalled in 64 available presets, including all input and output levels
  • Firmware upgrade and Preset management via USB
  • No more need for multiple firmware versions for different instruments. One firmware for all instruments!
  • Support for stereo and dual source pickups with switchable 9V mic bias on Ring
  • Enhanced EQ controls adds parametric mid boost/cut and high-pass, along with low and high shelf/bell
  • Stereo capable Effects Loop with separate Send and Receive jacks
  • Aux in for playing along with stereo input sources
  • Headphone output can also be used as a stereo line output

Features retained from the original Tonedexter

  • Works on any acoustic instrument, with most active or passive piezo pickup systems
  • Mute switch that activates a built-in high precision tuner, accurate to within 1 cent
  • Boost switch for solos with 0-8dB extra gain
  • Character control adds additional punch to the WaveMap
  • Latency less than 1ms
  • 1/4″ pickup input, 1MΩ (or 10MΩ with cable mod)
  • 1/4″ line output with output level control
  • XLR DI output with output level control
  • Analog boost and mute circuits positioned after effects loop, so no headroom loss when boosting
  • XLR mic input with 48V phantom power
  • +/-15V internal supplies for professional headroom and dead quiet operation
  • 6.3″ (160mm) W x 5.9″ (150mm) D x 2.3″ (58mm) H
  • 2.0 lbs (.907 kg)

Some Specs

  • Works on any acoustic instrument, with most active or passive piezo pickup systems
    • 1 MegOhm input impedance, and is switchable to 10 MegOhm if using a TRS (Tip/Ring/Sleeve) cable with the "ring" disconnected
  • Stores 32 custom WaveMaps
    • Support for transferring/storing/importing WaveMaps via USB/Web Interface
  • Mute switch that activates a built-in high precision tuner, accurate to within 1 cent
  • Boost switch for solos with 0-8dB of settable gain via rear panel pot
  • Bass, Mid and and Treble PARAMETRIC EQs
  • Variable High Pass filter
  • Spaciousness control adjusts time spread of impulse response, from 0% to 200%
  • Smart feedback control reduces your unique resonance hotspots from 0 to 200%
  • MIDI Program Control
  • External Footswitch Control
  • Latency less than 1ms
  • Effects loop (TIP send, RING return)
    • Loop stays "Active" when mute is pressed
  • 1/4" pickup input, high impedance (1MO)
  • 1/4" line output with output level pot on front panel
  • XLR DI output
  • Analog boost and mute circuits positioned after effects loop, so no headroom loss when boosting
  • XLR mic input with 48V phantom supply, used for training
  • Headphone output
  • Phase (polarity) switch on rear panel
  • +-15V internal supplies for professional headroom and dead quiet operation
  • 6.3" W x 5.9" D x 2.3" H


  • Do you need to store a separate wave map for pizzicato and bowed playing?

    No, and in fact, you probably shouldn't. I recommend doing both pizz and arco when creating your tone map(s) - the response of the pickup will then emulate the sound of the microphone no matter how you are playing. James, at Audio Sprockets, recommends doing some bowing when tone-mapping (even if you don't play arco), as it provides a better overall map, anyway.

  • I see it has 32 Tonemap memory locations. Why do I need so many?

    It seems the primary purpose for these is so that during the learning process you can try "recording" from several different microphone positions (or even different microphones) and then later pick the one you like best.

  • But could I keep up to 32 profiles and easily switch between them?

    I can imagine different songs in my repertoire, perhaps played in different ranges on the instrument, or maybe calling for different tonal "feel" based on the mood of the song. So, sure!

  • Is that possible, and fairly easy to do in a gig situation?

    It's easy to switch profiles - just a turn of the knob (with a digital readout confirming the location number) but again; you'll probably create that one setting that just sounds the most like your acoustic bass, and use that for everything; changes in your tone will mostly be done with your hands. That said, there's no reason that you couldn't create "tones" using different mics (like an old crystal mic, or some other timbrally distinctive mic) and dial them in for particular effect.

  • Can I share my WaveMaps from my ToneDexter with someone else?

    Starting with the firmware v1.4, released Aug 8 2018, there is now support for getting WaveMaps into and out of the unit. It requires a separate procedure using the Transfer Utility which copies all WaveMaps onto an SD card, and optionally writes externally saved WaveMaps back into the unit. WaveMaps may be archived in libraries, sorted and/or renumbered to create new sets for reloading. WaveMaps are stored in a proprietary file format that only works in a ToneDexter.

  • Will someone's WaveMap of their amazing carved bass make my crummy, beat up doghouse bass (or electric upright) sound amazing?

    Unfortunately, it doesn't quite work that way; the Tonedexter crafts the tonemap to the characteristics of the particular bass (and the pickup that’s on it.) So the resulting tonemap is tailored specifically to that bass and pickup. “Tailored” is a good word to use; it’s kind of like asking, “I got a suit custom-tailored to fit me; I’d like to know if it will look good on my friend if he borrows it?” The answer is, “maybe” – it depends on how similar his physique is to yours.

    So while we could create and share wavemaps made on, for instance, my fully carved bass using a high-end studio mic, we know that the micro-EQ and phase alignment changes that the ToneDexter applies will make that pickup on my bass sound very much like the mic I used for training. However, on a totally different bass (yours) with quite possibly a different pickup, those changes that the WaveMap applies to the pickup signal will not necessarily have the same effect -- and will almost certainly not produce the same tone. The real magic comes from getting the exact signature sound from your bass from the pickup you’re using to be "matched" to your bass' actual mic'd sound – and that's how you get a WaveMap that actually works well. That said, it would be fun to experiment with trading "patches" with other players, they might bring some interesting results.

    Also of note, we've been working, on and off, to create (using some complex home-studio trickery inspired by James at AudioSprockets) WaveMaps that can be applied to NS Design Electric Upright Basses. Since those basses are all made to be highly consistent, using the same pickups, it stands to reason that a WaveMap that made my NS Design WAV4 sound good would also work on yours. We haven't come up with anything that works just yet, but we're hopeful that we may arrive at a WaveMap that can bring a lot more realism to the sound of those basses. Stay tuned!

Confused? I hope not, but we're here to help if you have specific questions. We also, as usual, include a Gollihur Music Tip Sheet along with your purchase to help you get the most out of this unit when it arrives!

Product Manual

Need to figure out some of the more in-depth features of this product? There's a copy of the manual, in PDF format, in the "Product Manual" tab. (You may wish to visit the manufacturer's website to see if a more recent version is available.)




View AllClose

6 Reviews

  • 5

    It’s fantastic

    Posted by Bill M on Apr 3rd 2018

    I got my ToneDexter... this is probably the one tool that makes the biggest difference for me...

View AllClose