A powerful tone-carving tool that helps you transform a tired sonic recipe fast.
Intuitive operation. Streamlined design. Easy to dial in transformative sounds.
No dedicated footswitch for boost/overdrive.
$280
API TranZformer GTR
apiaudio.com
When it comes to underappreciated pedals, it’s hard to top the humble EQ. Yet these superficially unexciting stomp pedals can enable reproduction of elusive recorded sounds, salvage an unruly fuzz or amp, enliven a dull-sounding rig, or radically transform it from tune to tune. Why EQ pedals aren’t a more regular pedalboard fixture is puzzling. But the API TranZformer GTR underscores the immense potential of using a good one—particularly when you throw a nice preamp in the mix.
Kind of Blue
If the GTR looks familiar, it’s because you might have run across one of its rack-mounted antecedents in a studio. Anyone who has ever worked with a 550-series rackmount EQ on a recording project will recognize the API’s signature cut/boost knobs, the peak/shelf switch (which on the GTR works with the 5kHz band), and the same basic 3-band structure as the 550 series. The TranZformer circuit is based on the vintage 553 Program Equalizer, and by using similar, familiar controls and functionality, the GTR achieves the same intuitive feel that makes the 550 easy to work with in a studio.
Detents in each tone knob make tuning by feel and ear fast and easy. And the boost input gain knob starts at true 0 dB of boost, so you can dial in an initial EQ profile free of preamp color, add gain, and adjust the EQ again to taste in a natural, incremental process. It’s a great layout for finding tones fast—and even committing them to muscle memory.
There are three toggles situated below the EQ and preamp gain knobs. The rightmost toggle activates a -20 dB pad, which is critical if you want to utilize the full range of the pedal’s gain knob. The middle toggle switches between shelf and peak EQ settings for the high-frequency range. The peak setting, which emphasizes a specific section of the EQ curve, sounds airier in most positions, but it’s instructive to switch between the two at a given EQ setting to hear how shelved and peaked 5kHz-range settings interact with various settings in the other two bands.
A little extra treble and midrange, and a dash of overdrive-mode distortion, gives a Fender amp a cool, unmistakably Vox-y edge.
Switching into overdrive mode gives the pedal’s preamp an extra push. In low gain settings, the differences between overdrive and boost modes aren’t always wildly different. But the distortion gets meaner with just a dollop of extra midrange, and adding gain reveals an organic, growling tonality that feels direct and dovetailed with amplifier tones.
Room to Wiggle
The GTR’s EQ and gain controls give you many means for matching your guitar and pedals to unfamiliar amps. Better still, it helps you surgically shave, carve, recast, and bolster tones from the amps and pedals you already know. I love the sound and feel of the Telecaster/Tremolux tandem I used for most of this test. And I was pretty impressed at how the API could make the black-panel Tremolux sound like a bigger, more excited version of itself without compromising the amp’s personality. A little extra treble and midrange, and a dash of overdrive-mode distortion, gives the Fender amp a cool, unmistakably Vox-y edge. At even more advanced mid, treble, and bass settings, the pedal coaxed tweed-leaning voices when I tweaked the amp tone just right. All these colors were easy to find quickly and intuitively. And in a studio situation, where you like to keep things moving at a steady clip, I would probably much rather try to fine-tune a drive sound using a simple amp and the API than switch between a half-dozen overdrives to find some just-right tone recipe. If your amp is in decent working order, the GTR is likely to unleash some bigger, fatter, meaner, or more vibrant alter ego.
The Verdict
I love the GTR’s simplicity. And the high-quality build and low noise are evidence that API didn’t cut corners. Still, for $280 some might expect a second footswitch for the boost/overdrive section. And though the analog purity of the GTR is also awesome, I’m sure a lot of players will hear the breadth of extra colors the GTR enables and crave presets. On the other hand, the GTR is effectively three pedals in one, which makes the price look a lot more palatable. Plus, considering the way the GTR makes you less inclined to chase a new amp, perhaps you can consider pennies saved in the cost as well. The TranZformer GTR may not totally succeed in making EQ sexy, but its streamlined design, utility, and capacity to give new life to tired tone recipes are creative gold.
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Walrus Audio's MAKO MkII Series offers premium all-in-one, multi-algorithm pedals with improved tonality, new UI, and added controls for versatility. Featuring new amplifier models, OLED navigation screens, and updated programs based on user feedback, these pedals are designed for inspiring studio-grade tones.
Walrus Audio is excited to announce the release of their highly ambitious and highly anticipated MAKO MkII series. With the original MAKO line, players were offered premium all-in-one, multi-algorithm models for with the D1 Delay, R1 Reverb, and M1 Modulation, as well as top-of-the-line amp and cabinet simulation with the ACS1. After four years of real-world use and experience with the first generation, the team went to work applying everything they learned and heard from players to make the next generation of MAKO pedals even better.
Each pedal in the MAKO Series has been redesigned and rebuilt for vast improvements in tonality, new UI with the addition of an OLED navigation menu screen, and added secondary controls for even greater versatility. Dialing in these inspiring studio grade tones has never been easier and has never sounded better.
The ACS1 MkII features three new amplifier models to go with the three existing models, all inspired by high-gain amps for heavy-style players to get people moving:
- The distinctively raw and punchy Peavey® 5150.
- The warm, rich, and harmonically complex Orange® Rockerverb.
- The world-famous, in-your-face Mesa Boogie® Dual Rectifier.
Additional updates on the series are as follows:
- OLED navigation screen menu for improved UI.
- Increased headroom and lowered noise floor for tonal improvement.
- Rebuilt and fine tuned programs based on user feedback.
- All six R1 programs completely rebuilt from the ground up.
- All new Grain Delay algorithm on the D1.
- Six additional cabinet models for the ACS1, designed by Justin York at York Audio.
- Total BPM Control and BPM Readout on screen for time-based effects.
- Now 128 on-board presets.
- Many new program controls (ex. size control on R1, noise gate on ACS1).
- Flanger sound added to the Chorus algorithm on M1.
MAKO MkII Series pedals are packaged in custom anodized aluminum enclosures. Exact sizes for all four pedals is 4.9” x2.52” x 2.64”. Power requirement for all four pedals is 9VDC (300mA minimum).
Walrus Audio is offering the R1 MkII, D1 MkII, and M1 MkII for $399.99. The ACS1 MkII is offered at $449.99. All are available for preorder now at walrusaudio.com and through authorized dealers with expected shipment starting in mid-October.
For more information, please visit walrusaudio.com.
Here’s how to recreate the wide-ranging Epiphone Tone Expressor system on your guitar.
Hello and welcome back to Mod Garage! This is the second part of the Mod Garage look at the Epiphone Tone Expressor system (Pt.1), which is found on the Al Caiola signature model that was built from late 1963 until 1969. After discussing the individual parts and settings last month, we will now bring it all together and see how to use the system in a modern guitar.
In general, it’s possible to use the Varitone/Tone Expressor system in any electric guitar as long as you have enough space to squeeze all the stuff into it. You can mimic a lot of different pickups with this system, but because it’s designed for guitars with humbuckers, that’s how it works best. It’s also possible to use it the other way around and thicken up single-coil pickups instead of slenderizing humbucker tones, and in a future column I’ll talk about what I like to call the “reverse Varitone” system.
For a good and simple overview about all the details from last month, I decided to use a technical drawing to show the isolated Varitone system, so it’s easy for you to identify the individual parts:
Diagram courtesy of SINGLECOIL
This is the basic structure of the Gibson Varitone system with the original values Gibson used. The inductor is a 1.5 H choke. The Epiphone Tone Expressor system is identical but uses a 15 H choke as an inductor. There is a second version of the Tone Expressor system found on the Al Caiola model using the same structure but with different values for the parts. I think this was because different pickups were used, so here are the values for the version of the system in the Al Caiola guitar:
• 15 H choke as an inductor instead of 1.5 H
• Replace the single 100k resistor with a 33k resistor
• .0033 µF cap is used instead of the .001
• .01 µF cap is used instead of the .0033
• .022 µF cap is used instead of the .01
• .047 µF cap is used instead of the .03
• .1 cap µF is used instead of the .22
For best results, use the original Gibson Varitone values along with PAF-style humbuckers—the second version will work best with mini-humbuckers or similar pickups. Depending on the pickups you use, you can experiment and make your own custom version out of it.
“You can mimic a lot of different pickups with this system, but because it’s designed for guitars with humbuckers, that’s how it works best.”
The differences are:
• Using a 15 H instead of the 1.5 H inductor will shift the notches of the filters created by the Tone Expressor system down approximately a fifth for a fuller and fatter tone. Because it is possible to combine several caps with this wiring, choosing a 15 H inductor was also a clever move to keep the tone clearer and more present. You can experiment with this, too. A choke with something between 7 and 10 H will be in the middle of both versions.
• Using a 33k instead of the 100k coupling resistor fits pickups with a lower output like the mini-humbucker perfectly, while the 100k is great for pickups with more output like a PAF.
• The different cap values also correspond to the combination of different pickups and chokes, e.g., for a twangy, Telecaster-type tone, you need a 0.22 µF cap along with a PAF humbucker, while a 0.1 µF cap will do the same along with a mini-humbucker.
So, here we go with the Al Caiola wiring, starting with how it looks in the original guitars from the ’60s. You can clearly see the big, silver-cased choke on top of the electronics as well as the caps, resistors, and the individual switches.
Photo courtesy of Bonfires Vintage
And here is the drawing of the Tone Expressor system I made for you:
Drawing courtesy of SINGLECOIL
All switches are DPDT switches, the tone and volume pots are both 500k audio, and the tone cap is 0.022 µF. A is the coupling resistor (33k or 100k), B is the five 10M ohm pulldown-resistors (one on each switch), which prevent popping noises when engaging a switch, and C is an additional 33k decoupling resistor on each switch that is necessary to decouple the switches from each other when you want to combine their settings. You don’t need that on the Varitone because you can’t combine several caps with the rotary switch.
Besides experimenting with the parameters of the choke, the caps, and the coupling resistor, you can enhance your tonal palette quick and easy by using a pickup selector switch that can engage both pickups together.
In closing, here is a scaled-down version of this wiring, in case you don’t want to use a choke or can’t find one.
Drawing courtesy of SINGLECOIL
As you can see, the coupling resistor (A) and the decoupling resistors (C) are removed. That’s because in the system with the choke (second order filter system), these are necessary, but without a choke, they’re not.
That’s it. Since we are still in the year of the Strat, next month we will have a look into the Fender Cory Wong Stratocaster, so stay tuned!
Until then, keep on modding!
Whether you’re tired of slinging combos and bigger into your car’s trunk or looking for reliable backup and backline power, these pedal-sized options have plenty to offer.
Here’s a rundown of six amps in a stompbox format. Carry soft, play loud!
Blackstar Amplification AMPED 2
A portable 100-watt pedal amp with onboard effects that’s perfect for the guitar player that wants an all-in-one watt-cranker and an effects processor
blackstaramps.com
NUX Amp Academy (NGS-6)
This compact workhorse offers 18 amp models, seven signal blocks, independent outputs, and a robust IR loader—plus, it functions as a USB audio interface.
nuxaudio.com
MayFly Audio Sunrise Amp Simulator
The MayFly emulates the classic sound of black-panel amps, including their preamp, power amp, speaker cabinet, and spring reverb. It's intended to plug directly into a PA or DAW, and includes a stereo headphone output jack.
mayflyaudio.com
Friedman IR-D
The IR-D dual-channel tube preamp is an entire Friedman rig, inspired by the JTM45, in a compact pedalboard-friendly package.
friedmanamplification.com
Strymon Iridium Amp and IR Cab Pedal
The Iridium offers three iconic tube amplifier models and nine super-high-resolution, 500 ms impulse response speaker cabinets, along with size-adjustable IR-based room ambience.
strymon.net
Revv Anniversary Series G3
The new Anniversary Edition Revv G series pedals feature new aesthetics and even more amp-like feel and tone—modeled after Revv amps’ purple channel.
revvamps.com
Polyphonic pitch shifting, adjustable ramp speed, and three-way tone switch.
Octa Psi Features:
- Instant Effect Order Switching: Solve the classic question "Octave/Pitch before or after fuzz?" with ease –just hold down both foot switches.
- Flexible Output Configuration: Switch between AllWet or Wet/Dry blend with a quick double-tap of Blend.
- Momentary or Latching Octave/Pitch: Switch between latching or momentary octaves for completecreative control, simply hold the Fuzz switch.
Polyphonic Octave and Pitch Shifter:
- Three Modes: Up, Down, and Dual modes for creating nearly every harmonic interval, includingpower chords, stacked fourths, and diminished chords.
- Momentary Mode: Perfect for dive-bombs and wild multi-octave bends.
- Adjustable Ramp Speed: For creatively timed pitch bending, just like having an onboardexpression pedal.
Transfigurating Fuzz Circuit:
- All-Analog, Transistor-Based: Delivers incredible sound with wave after wave of gain staging leading to hard clipping.
- Three-Way Tone Switch: Carve out the perfect fuzz tone with Scoop, Punch, or Psi mode.
- Massive Sound: Makes your guitar pickups sound enormous at any volume.
Stunning Design and Ease of Use:
- High Octane Circuitry – Housed in a proprietary angled aluminum enclosure for simplicity and durability.
Upgrade your sound and explore new sonic possibilities with the Octa Psi Transfigurating Fuzz Pedal.Prepare yourself to experience the ultimate in pitch-shifting, octave generation, and analog fuzz!
Octa Psi Highlights:
- Polyphonic Pitch Shifter:○ +/- Two Octave Range and nearly every harmonic interval.
- Low latency and fast-tracking for great tone in dropped tunings or wild bends.
- Switchable All-Wet ⇆ Wet/Dry Blend by double tapping the Blend control.
- Momentary or Latching Octave and Pitch Shifter by holding down the Fuzz stomp.
- Adjustable Ramp Speed for the pitch shifter by holding Octave down and adjusting Blend.4
- Three pitch-shifting modes (Up/Dual/Down) for multiple octaves, crazy intervals, chords,and even chorus modulation.
- Analog Transistor Fuzz:
- Super thick, analog transistor fuzz and distortion.
- Three-way bass response: Scoop, Punch, or Psi mode for massive undertones.
- Order switching between Fuzz ⇆ Octave (Pitch) by pressing and holding both Octave andFuzz.
Tech Specs:
- Pedal Type: Octave Fuzz and Pitch Shifter
- Switching: Momentary or Latching Pitch Shifter
- Analog/Digital: Mixed, Analog Fuzz & Digital DSP
- Effects: Polyphonic Pitch Shifter, Octave, Fuzz, Distortion
- Inputs/Outputs: TS 1⁄4” jacks
- Bypass: True Bypass or Silent Buffered Bypass, user selectable
- Power Requirements: 9-18 VDC, 150mA (high current power supply sold separately) - No battery
- Height: 2.7”
- Width: 3.9”
- Depth: 5”