Guitarists are constantly on a quest for the perfect tone, and the setups of legendary players like John Mayer are often a source of inspiration and intrigue. While searching for resources like “Board And Raised Guitar Tab John Mayer,” many players delve into Mayer’s gear in pursuit of his signature sound, particularly from albums like “Born and Raised.” This exploration often leads to the discovery of unique and sometimes mysterious components within his signal chain. One such intriguing piece of gear, initially shrouded in secrecy, is the “box-a-lator.”
This article dives deep into the “box-a-lator,” a pedal design born from curiosity and inspired by a Dumble creation spotted on John Mayer’s pedalboard. While not directly related to specific “board and raised guitar tab john mayer” searches, understanding Mayer’s gear philosophy and his use of tone-shaping tools provides context for appreciating the versatility and ingenuity of the box-a-lator. Let’s unravel the mystery behind this pedal and explore how it can be a valuable asset in any guitarist’s rig.
Unveiling the Mystery: The Box-A-Lator’s Origins
The journey to create the box-a-lator began with a keen observation of John Mayer’s 2021 Dead & Company pedalboard. Amidst the familiar array of pedals, a small, enigmatic black box with minimal controls sparked intense speculation among gear enthusiasts. The online forum “My Stupid Mouth,” a hub for John Mayer gear discussions, buzzed with theories about the identity and function of this mystery device.
John Mayer’s 2021 Pedalboard
Collaborating with Alejandro from johnmayergear, the discussion ventured offline, focusing on deciphering the name of the pedal. The breakthrough came with the recollection of a Dumble “thing” Mayer had showcased on his Tumblr account years prior. Although the original Tumblr post is no longer accessible, thankfully, the internet archive preserves this piece of gear history. Furthermore, the device appears in John Mayer’s 2013 behind-the-scenes videos, offering additional glimpses. A close look at the caption from Mayer’s Tumblr post reveals the likely origin of the name “box-a-lator.”
John Mayer’s Tumblr Showing Off his A Box Later Dumble FX Loop
John Mayer Born & Raised Sessions Screen Shot
This discovery ignited a quest to understand the inner workings of this Dumble device. A thread was initiated on The Amp Garage (TAG) forum, seeking insights into its circuitry. Initial speculation leaned towards it being an FX loop similar to Dumble’s Dumbleator. While the presence of send/return jacks on the original Dumble unit remained uncertain, it was a reasonable assumption. Adding to the intrigue, a post by Josh from JHS Pedals on August 16, 2021, showcased the device on Mayer’s pedalboard, cleverly blurring out the name but teasingly captioning it “SOMETIMES MYSTERY IS A GOOD THING!” This post, along with enhanced photos from dedicated forum members like omega0jm on the MSM forum, confirmed the name “box it later” (or “box-a-lator”) and strengthened the belief that it was indeed a clone or a very close relative of the Dumble device.
Josh @ JHS Instagram
John Mayer’s 2021 Pedalboard
Further investigation on ampgarage led to a significant breakthrough. Legendary amp tech Gil Ayan shared previously unseen internal photos of the original Dumble “a box later.” These photos provided invaluable clues about its construction and circuitry.
Dumble “a box later” Guts
Dumble “a box later” Guts
Dumble “a box later” Guts
Dumble “a box later” Guts
Dumble “a box later” Guts
Dumble “a box later” Guts
These photos revealed several key details: multiple units existed, the circuitry was op-amp based, and forum members noted a bipolar power supply and a B2K potentiometer on the “drive” control. dbharris on ampgarage suggested that Dumble might have drawn inspiration from FX loop op-amp designs in amps like the JCM 900. Fueled by these insights, the design process for the box-a-lator commenced, incorporating elements from 90s op-amp based FX loops and the visible components in the Dumble photos.
Dumble “a box later” Layout
Analyzing the photos further, the “IN” connection appeared to link to resistor R7. The recovery pot’s placement seemed consistent with traditional Dumbleators, although less common in op-amp designs. Despite uncertainty about its value, a 1MA pot was initially chosen for the design, aiming for typical impedance but acknowledging potential quirks in the sweep.
The Design Philosophy Behind the Box-A-Lator
Based on the gathered information, a design concept for the box-a-lator began to take shape, guided by these key objectives:
- Bipolar Power Supply: Employing a +/- 15V supply to maximize headroom for the op-amp, ensuring clean signal handling.
- B2K Drive Pot: Replicating the observed B2K potentiometer for the Drive control.
- Flat Frequency Response: Striving for sonic neutrality, preserving the original tone as much as possible.
- Tantalum Capacitor: Incorporating a tantalum capacitor, likely for a boost function within the circuit.
- Pedal and Amp Friendly Impedance: Designing input and output impedances compatible with both guitar pedals and tube amplifier FX loops, mirroring John Mayer’s versatile pedalboard applications.
- Compact Enclosure: Fitting the circuit into a pedalboard-friendly 1590BB or slightly taller 1590BBS enclosure.
- Dumble/JHS Aesthetics: Visually paying homage to both Dumble’s design language and JHS’s “box it later” aesthetic.
- Post-Return Boost Circuit: Including a boost circuit positioned after the return stage for added versatility.
To achieve these goals, several circuits were studied and referenced:
- AionFX L5 Preamp: Utilizing its +/- 15V power supply design for clean and ample headroom.
- Marshall FX Loop Circuits: Analyzing schematics from various Marshall amps known for their op-amp based FX loops.
- Barbarach Thunder Boost Circuit: Drawing inspiration from this simple and effective op-amp booster design.
Marshall FX Loop Schematic
Marshall FX Loop Schematic
AionFX L5 Preamp Power Supply
Thunder Boost Schematic
Addressing the impedance challenge for both pedals and tube amps, trim pots were implemented. Inspired by variable input impedance found in Marshall FX loops, the box-a-lator design utilizes trim pots to fine-tune impedance. A 68k resistor sets the lowest input impedance, while a 1M trim pot allows adjustment up to 1M. Similarly, the return circuit features a trim pot controlling output impedance, ranging from a minimum set by a 10K resistor (R9) to a maximum of 1M. The “RECOVER” pot in the return circuit provides high-end roll-off, useful for taming bright preamps. By default, both trim pots are set to 1M to maintain a full frequency spectrum. These trim pots were labeled “DRAG” pots to reflect their impedance-altering function. The schematic evolved through versions, with v1.1 and v1.2 primarily differing in the addition of a SOIC footprint to accommodate both DIP and SOIC op-amp chips.
box-a-lator Footswitch Schematic
Legacy box-a-lator Signal Schematic
Updated schematic with A10K pots
box-a-lator v2.0 Signal Board
The physical layout prioritized minimizing noise. While a single PCB design was initially considered, the potential for noise interference from the DC-DC converter led to a two-board solution, separating the footswitch and signal circuits. Inspired by the low-noise performance of a previous 4-layer board design (ATS808), a 4-layer board was chosen for the box-a-lator signal circuit. This approach, with ground pours on the top and bottom layers and signal traces surrounded by ground on the inner layers (creating mini coax cables), aimed for a hi-fidelity and low-noise floor, crucial for a pedal intended for transparent signal manipulation. The footswitch board remained a standard 2-layer design. Both boards incorporated “improved fabrication” techniques with vias strategically placed to connect layers for uniform grounding and structural reinforcement.
box-a-lator Board Layout
box-a-lator Board Layout
box-a-lator v1.2
Assembling Your Box-A-Lator
To minimize potential ground loop issues, isolation jacks like Neutrik NMJ4HC-S are recommended for the box-a-lator build. Future iterations might incorporate a ground lift switch, but for now, manual ground wire adjustments for the SEND/RETURN jacks may be necessary. Crucially, the enclosure itself is not grounded. Therefore, a wire should be soldered to the footswitch lock washer and connected to the input jack ground to establish a star-ground configuration, ensuring all grounds converge at a single point.
box-a-lator wiring diagram
Footswitch Grounding
Footswitch Grounding
The provided drill template accommodates both 1590BB and 1590BBS enclosures. The slightly taller 1590BBS is recommended, especially for pedalboard use, as it aligns better with the height of standard pedals. For tube amp FX loop applications, size may be less critical, but the 1590BBS can still simplify assembly due to its increased internal space.
BOM information, including a convenient MOUSER project link, is available at:
https://docs.google.com/spreadsheets/d/1aC4ULW50eoGUjiOnjHFqkAqDp1eSRMveEHBwo_skGSQ/edit?usp=sharing
EDIT 3/15/24: It is recommended to use an A10K potentiometer for the recovery pot instead of A1M for finer control over FX loop return levels.
For build photos and further research, refer to this Google Photos album:
https://photos.app.goo.gl/zfz8smN7v1KggQku9
Component Selection Notes:
For a low-noise build, metal film resistors are advisable. Capacitor selections are component-specific, with solid polymer electrolytic capacitors used in the power supply for longevity and low ESR. A non-polarized electrolytic capacitor is included as a nod to the original Dumble design. While Dumble likely used a TL072 op-amp, the OPA2134, designed for audio applications, is preferred for its sonic performance.
V1 Prototype box-a-lator
V1 Prototype box-a-lator
!!!YOUTUBE BUILD VIDEO COMING SOON!!!
Unleashing the Potential: Using the Box-A-Lator
The box-a-lator’s versatility stems from its clean and neutral signal path, as evidenced by these performance graphs:
Unity Gain Recover Circuit
This graph illustrates the box-a-lator’s transparency with DRIVE and RECOVER at 100% (unity) and boost at 0%.
Max Boost
This graph demonstrates the boost circuit’s neutrality at 100%, with minimal roll-off in guitar frequencies.
Total Loss Through FX Loop
This graph shows the minimal tonal alteration and slight level dip when running a signal through the FX loop using a 25-foot budget cable.
Max headroom with OPA2134
This graph highlights the benefit of the +/-15V bipolar power supply, showcasing the ample headroom provided by the OPA2134 op-amp, with minimal clipping even with a strong input signal and significant boost.
So, how can you integrate the box-a-lator into your rig? Here are several applications:
Use Case 1
Use Case 2
Use Case 3
- Signal Attenuation: Similar to John Mayer’s observed usage, the box-a-lator can attenuate hot signals. By patching a short jumper cable between the SEND and RETURN jacks, you can tame overly saturated pedals without sacrificing their core tone, preventing them from overwhelming subsequent pedals in your chain.
- Tube Amp FX Loop Utility (Dumbleator Style): Employ it in your tube amp’s FX loop like a traditional Dumbleator. Crank your preamp for desired overdrive and use the box-a-lator to control the signal level hitting your power section, preventing unwanted power amp saturation.
- Long Cable Run Buffer: Use it in your amp’s FX loop to maintain signal integrity when running post-preamp effects through long cable runs, mirroring another function of the Dumbleator.
- Neutral Buffer/Clean Boost: With DRIVE and RECOVER at 100%, the box-a-lator functions as a pristine buffer. Engage the boost for a transparent volume increase without coloration.
- Multi-Pedal Loop Switch: Place a chain of pedals in the box-a-lator’s FX loop and use its footswitch to engage or bypass the entire chain simultaneously. This is particularly useful for managing multiple pedals or addressing pedals with finicky footswitches.
- Creative Applications: The box-a-lator is a versatile tool, and further applications are sure to emerge. Share your innovative use cases and they may be featured here!
!!!HOW TO USE THIS PEDAL VIDEO COMING SOON!!!
