The range runs from traditional tremolo pulses to a rotary cabinet simulator modeled on a Leslie speaker, plus a vibrato mode aimed at the Uni-Vibe sound123. DigiTech describes the four tremolo types as emulating "anything from warm amp-like pulses to helicopter chop, or separate 2 trems at once"4. It is a true stereo pedal with two inputs and two outputs, so you can run a second guitar or a second amp43.
Seven modulation effects in one stereo pedal
The Type knob selects between the seven modes3. Vintage Guitar listed them at launch as Tremolo, Opto-Tremolo, Bias Tremolo, Duo Tremolo, Rotary, Vibrato and VibroPan5, and Guitar World's review grouped them as opto tremolo, bias tremolo and duo-trem, plus a rotary speaker effect, vibropan and more523.
| Mode | What it does |
|---|---|
| Tremolo | Basic tremolo effect6 |
| Opto Tremolo | Imitates the circuit found in vintage Fender amps3 |
| Bias Tremolo | Based on the Vox sound3 |
| Duo Tremolo | Two trems at once; a stuttering rhythm effect43 |
| Rotary | Emulates a Leslie rotary speaker cabinet3 |
| Vibrato | Pitch modulation5 |
| VibroPan | Stereo panning tremolo5 |
The two amp-style tremolos are the heart of the pedal for many players. Opto Tremolo copies the photocell circuit of vintage Fender amplifiers, while Bias Tremolo follows the Vox approach of modulating the tubes' bias, which gives a different character of pulse3. Duo Tremolo runs two tremolos separately, which Premier Guitar's reviewer found produced "a stuttering rhythm effect on the Duo Trem setting was very cool"3.
The controls: Speed, Depth, Modify and Type
The TR-7 keeps things simple with four heavy duty knobs: Speed, Depth, Modify and the Type selector37.
| Control | What it does |
|---|---|
| Speed | Controls the speed of the effect3 |
| Depth | Controls the intensity3 |
| Modify | Controls various settings depending on which effect is in play3 |
| Type | Selects any of the seven effects3 |
MusicRadar noted that each mode is controlled by the usual Speed and Depth knobs8. The Modify knob controls various settings depending on which effect is in play, and the Type knob allows you to select any of seven effects3.
Power and connections: stereo I/O, true bypass, high-voltage rails
The TR-7 powers up with a 9V battery or a 9V DC center negative adapter43. It features true stereo I/O, allowing for complex connections, creative flexibility and, in Premier Guitar's words, "trippy sounds"3. With two inputs and two outputs you can add a second guitar or amp3.
True bypass and high-voltage rails are HardWire's standard extreme performance features2. Premier Guitar described the constant high-voltage operation as being for "top-notch tonal quality and noise reduction"3.
The high-voltage rails mean the pedal's internal circuit runs at a higher voltage than the 9V coming in, a HardWire series feature aimed at headroom and quiet operation32.
History: part of DigiTech's HardWire series
What reviewers said about the tremolo, rotary and vibe modes
Reviews split along the line between the tremolo modes and the emulation modes. MusicRadar's verdict on the tremolos was direct: "The different modes nail all of the tremolo sounds you're likely to need"8. Premier Guitar's reviewer found the Opto Tremolo and Bias Tremolo modes very satisfying3.
The rotary and vibe modes drew a more mixed response. Premier Guitar's reviewer wrote that the Rotary setting "lacked the lush warmth of other pedals that do a better job of emulating that sonic territory and made me wish for the real thing"3. The overall verdict:
"The tremolo and vibrato sounds on the TR-7 are great, and the Uni-Vibe and Leslie sounds aren’t so great. It gets you in the ballpark, but those with educated ears will have issues and should look elsewhere."
DigiTech describes the Ultravibe mode as offering "slow phasey goodness and a liquid-like vibrato"4.
On value, the two reviews differed in currency and tone. Premier Guitar listed the street price at $189.953, while MusicRadar reviewed it at £150 and concluded "At £150 we'd say it's a good rather than outstanding deal"8. Premier Guitar's buying advice was to buy if tremolo is your life and skip it if you require deep Uni-Vibe sounds, summing up that "tremolo freaks will surely dig it"3.
Videos
ProGuitarShopDemos
Guitar World
Premier Guitar
Questions
Does the HardWire TR-7 run on a 9V battery?
Yes. The TR-7 powers up with a single 9V battery or a 9V DC center negative adapter, so it works either way on a pedalboard or standalone. The HardWire series' constant high-voltage operation runs internally regardless of which power source you use.
Is the DigiTech TR-7 true bypass?
Yes. True bypass is one of the HardWire series' standard extreme performance features, along with high-voltage rails. When the pedal is off, your signal passes through without the circuit in the way.
Does the TR-7 have tap tempo?
Yes. All of the TR-7's modes can be controlled via tap tempo, so you can set the speed of the tremolo, rotary or vibrato effect in time with the music rather than dialing it in by ear.
Can the TR-7 do a Uni-Vibe sound?
Its UltraVibe mode is designed to give the classic vibrato of the Uni-Vibe, the sound heard on Pink Floyd's Breathe. Premier Guitar's reviewer found it only gets you in the ballpark, though, and suggested players with educated ears look elsewhere for that sound.
What is the difference between Opto Tremolo and Bias Tremolo on the TR-7?
Opto Tremolo imitates the photocell circuit found in vintage Fender amps, while Bias Tremolo is based on the Vox sound, where the tremolo modulates the tubes' bias. Premier Guitar's reviewer found both very satisfying.
Who makes HardWire pedals?
HardWire is a pedal series made by DigiTech. The line was positioned as extreme performance pedals with true bypass and high-voltage rails, and the TR-7 joined an existing lineup that included delay and echo pedals.
Sources (8)
- DigiTech Hardwire TR-7 Tremolo, Delicious Audio, 2010-07-30
- HardWire TR-7 Pedal Debut at Summer NAMM, Premier Guitar, 2010-06-18
- HardWire TR-7 Tremolo/Rotary Pedal Review, Premier Guitar, 2010-10-28
- Hardwire TR-7 by DigiTech, RockBoard, 2026
- HardWire Adds TR-7 Tremolo/Rotary Pedal, Vintage Guitar magazine, 2010-06-18
- Hardwire TR-7 Tremolo/Rotary Pedal, Delicious Audio, 2011-03-07
- Digitech Hardwire TR-7 Tremolo / Rotary Simulator, Pedal of the Day, 2014-10-05
- Hardwire TR-7 Tremolo/Rotary review, MusicRadar, 2011-12-02
