ToneDexter Tone-Correcting Preamp

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Our Price $399.00
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Product Overview

Audio Sprockets ToneDexter Preamplifier


Now, 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 into this HVB (Highly Visible Box) 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.

Now, 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 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.

A note about Firmware Versions:
The ToneDexter was originally developed for use with guitars and other higher pitched instruments. However, it was designed to be able to be upgraded with new features through upgrades to its firmware. Since introducing the ToneDexter, Audio Sprockets discovered how well it could work with basses, and developed a specific firmware (operating system) for bass instruments.

This alters a few key features; specifically, the WaveMap is longer, time-wise, operating on a different time base and sampling rate -- this allows for the lower range to be more accurately represented. Also, the EQ and notch ranges are optimized for bass frequencies.

Since most of our customers would prefer that the unit be tailored to be more bass-friendly, ToneDexters bought at Gollihur Music are updated to have the most current version of the Bass firmware preinstalled for you.

Are you planning on using it with a different instrument? No worries. Switching out is easy by downloading the alternate firmware versions from the Audio Sprockets website.) We also do try to keep 1-2 units set at the "General Firmware," which Audio Sprockets recommends for Guitar, Dobro, Viola, Cello, Bazouki, Mandola, Mandocello, Baritone Guitar, and other similar instruments. If you'd like us to send one of THOSE units, so you don't have to re-flash the firmware, just let us know in the text box at checkout.

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 22 custom WaveMaps, selectable via 11 position rotary switch and bank select switch
    •  Support for transferring WaveMaps in and out is now included with the v1.5 firmware. Requires Transfer Utility available at the AudioSprockets website.
  • 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 and treble EQ
    •  Bass EQ control is now a variable highpass filter when cutting.
  • Sweepable notch filter for feedback suppression
  • Character control which adds additional punch to the WaveMap
  • 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, with rear panel option switch for fixed level or level that follows output level pot
  • 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
  • SD card slot for field upgrade of software
  • 6.3" W x 5.9" D x 2.3" H
  • Forward-thinking design means that updated functionality may be available in the future with a simple downloadable firmware (operating system) update


  • 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 22 Tonemap memory locations. 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 22 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. 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 distinctively timbred 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.

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!


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