The RJM Music Mastermind GT/16 is a MIDI foot controller: a floor unit that sends MIDI commands to effects processors, modelers, profilers and switchers rather than processing your guitar signal itself. It sits in the middle of RJM's Mastermind GT family, between the 10-button GT/10 and the larger GT/22, and RJM describes the GT line as its flagship, "the result of years of research and development"123.
What sets the GT/16 apart from a basic MIDI footswitch box is its display arrangement: 16 buttons, each with its own LCD display directly above it. Any button can be set to perform any function, whether that is a preset change, an instant access (IA) command, bank up or down, or tap tempo, and the LCD above it shows what that button does at any moment1. For a player running a complex rig, that means no printed labels or masking tape: the controller tells you what each button is doing as your presets change.
RJM's store lists the Mastermind GT/16 as sold out, with a sale price of £1,518.00 GBP1.
What it is and what it does
The GT/16 is built for players whose rigs live on MIDI: profiling amps, modelers, rack effects and switching systems. It stores 384 presets organized across 16 pages of buttons and can address 16 connected MIDI devices1. In practice, a preset can change patches on several devices at once and reconfigure the button assignments, with the per-button LCDs updating to match.
The four expression pedal inputs accept linear or log pedals wired with TRS jacks, at high or low impedance, so most expression pedals will connect without an adapter1. Two TRS jacks add up to four external switches, and momentary switches are required1.
Power and connections
The GT/16 runs on 12V DC at 1.2A, center positive, through a 2.1mm ID / 5.5mm OD barrel connector1.
The barrel connector is center positive, the opposite of the center-negative standard used by most guitar pedals. A typical pedalboard power supply cannot power it, and the 1.2A draw is well beyond what a daisy chain can spare.
MIDI input and output use 7-pin DIN connectors1. In the GT family, a 7-pin MIDI connection can carry phantom power from compatible hardware: MusicPlayers.com's review of the GT/22 describes powering the controller over a six-pin XLR cable with RJM switching products like the Rack Gizmo or Effects Gizmo, or over 7-pin DIN MIDI, with a supplied external power supply for standard 5-pin setups2. The review notes that only the GT/22 offers the custom RJM XLR interface2.
How it compares with the GT/10
The GT/16's smaller sibling, the Mastermind GT/10, shares the same core design: 10 buttons, each with an LCD display over it, and any button assignable to any function3. The two differ mainly in size and preset count:
| Mastermind GT/16 | Mastermind GT/10 | |
|---|---|---|
| Buttons | 16, each with an LCD1 | 10, each with an LCD3 |
| Presets | 3841 | 7683 |
| Devices controlled | 161 | 163 |
| Expression inputs | 41 | 43 |
| External switches | 4, via 2 TRS jacks1 | 4, via 2 TRS jacks3 |
| MIDI connectors | 7-pin DIN1 | 7-pin DIN3 |
| Power | 12V DC @ 1.2A, center positive1 | 12V DC @ 800mA, center positive3 |
| Dimensions | 19.4 x 11.1 x 3.25 in1 | 19.4 x 8.1 x 3.25 in3 |
| Weight | 8 lb / 3.6 kg1 | 6 lb / 2.7 kg3 |
The GT/10 also adds a USB "A" connector for a USB thumb drive3, and more than one Mastermind GT can be connected together and used in multiple locations on stage3. RockBoard's PedalPedia describes the GT line, after nearly a decade on stages and in studios, as powerful and rugged, and the go-to controller for many of the world's leading touring bands4.
What reviewers said
MusicPlayers.com reviewed the GT family in February 2015, focusing on the GT/22. Reviewer Scott Kahn found the line easy to get running, noting an easy-to-follow instruction guide plus online video tutorials for setup with devices from Fractal Audio, Kemper, Strymon and more2. On the family's fit for modern rigs, he wrote:
"if we were looking for a foot controller to run a guitar rig built entirely around a modeling amp or profiler like the fantastic Kemper Profiling Amplifier, a Mastermind GT/16 or GT/10 would make a great choice."2
RJM's store lists the Mastermind GT/16 as sold out, with a sale price of £1,518.00 GBP1.
Videos
RJM Music Technology Inc
Questions
How many presets does the RJM Mastermind GT/16 hold?
The Mastermind GT/16 holds 384 presets, organized across 16 pages of buttons, and it can manage 16 connected MIDI devices at once. The larger GT/10's preset count is actually higher at 768, but both controllers address 16 devices.
Can any button on the Mastermind GT/16 be set to any function?
Yes. RJM Music states that any of the 16 buttons can be set to perform any function, including preset changes, instant access (IA) commands, bank up and down, or tap tempo. The LCD display above each button indicates what that button currently does.
How many expression pedals can the Mastermind GT/16 connect?
Four. The GT/16 has four expression pedal inputs, and it accepts linear or log pedals wired with TRS jacks, at either high or low impedance, so most expression pedals on the market will work.
What power supply does the Mastermind GT/16 need?
It requires 12V DC at 1.2A, center positive, on a 2.1mm inner diameter / 5.5mm outer diameter barrel connector. Note the center-positive polarity, which is the opposite of most guitar pedals, so a standard pedal power supply will not work.
Does the Mastermind GT/16 use 5-pin or 7-pin MIDI connectors?
The GT/16 uses 7-pin DIN connectors for MIDI input and output. A 7-pin connection can carry power over the MIDI cable with compatible hardware, which is how the GT family is typically used with RJM's own rack switchers.
How much does the Mastermind GT/16 weigh?
It weighs 8 pounds (3.6 kg) and measures 19.4 inches wide, 11.1 inches deep and 3.25 inches high (49.3 x 28.2 x 8.3 cm), so it is a substantial floor unit rather than a compact pedalboard accessory.
Sources (4)
- Buy the Mastermind GT/16 MIDI Foot Controller, RJM Music Technology, Inc.
- RJM Music Technology Mastermind GT MIDI Foot Controller, MusicPlayers.com, 2015-02-12
- Mastermind GT MIDI Foot Controller, RJM Music
- Mastermind GT/10 by RJM Music Technology, RockBoard PedalPedia, 2026
Rich Robinson
