GB – Guitar Buffer (J-FET Input Stage, Unbalanced)

For preserving guitar tone integrity when connecting to effects processors, pedalboards, and devices with inadequate input buffers.

The GB Guitar Buffer is a specialized signal conditioning tool designed to solve a critical problem: most mainstream guitar effects processors, pedalboards, and audio interfaces have mediocre input buffers that load down your guitar’s high-impedance signal, causing progressive high-frequency loss and tonal degradation. The GB bridges this gap, using the same discrete J-FET input stage found in our J-series professional DI boxes—but optimized for unbalanced guitar signal paths.

Sound Quality Characteristics

• Spectral Uniformity: The GB’s J-FET input stage presents an extremely high input impedance (≥4 MΩ), ensuring zero loading of your guitar’s pickups. No tone sucking, no high-frequency rolloff, no loss of dynamics. Your guitar’s original tonal character—pickup response, string attack, harmonic content—passes through completely unaltered.
• Transient Response: By presenting the ideal load to your instrument, the GB preserves the full frequency spectrum of your playing. The “snap” of your pick attack, the “bite” of aggressive playing, and the natural shimmer of high-frequency overtones are transmitted without degradation.
• Output Impedance Reduction: The GB’s low output impedance (<1 kΩ) converts your guitar’s weak, high-impedance signal into a robust signal capable of driving long cable runs, multiple pedal inputs, or devices with less-than-ideal input stages without tone loss.
• Pianissimo Clarity: With noise performance matching our J-series DI boxes, the GB preserves low-level playing detail. Fingerpicking, subtle dynamics, and ambient noise captured by your pickups remain audible and clear.
• Dynamic Range Preservation: Unity gain (0 dB) and high headroom ensure your full playing dynamics—from delicate fingerpicking to aggressive power chords—are passed through without compression or artifacts.

Technical Specifications

• Circuit Type: Discrete J-FET input stage (identical to J-series DI boxes)
• Gain: 0 dB (unity gain, 1:1)
• Input Impedance: ≥4 MΩ (4,000,000 Ω)
• Input Connector: 1/4″ TS jack (unbalanced, standard guitar jack)
• Output Impedance: <1 kΩ
• Output Connector: 1/4″ TS jack (unbalanced, standard guitar jack)
• THD @ 0 dBu: <0.002% (typical 0.0001%)
• Noise Floor: Excellent, matching J-series performance
• Headroom (THD <1%): >+8 dBu @ 9V, >+12 dBu @ 12V+
• Power Supply: 5.2mm barrel jack, center-positive, negative outside
• Voltage Range: +9V to +24V DC
• Current Draw: Minimal (J-FET topology)
• Topology: Pure J-FET buffering, Class A, no feedback
• Bypass: Not applicable (always active, unity gain)
• Enclosure: Aluminum, compact pedal format
• Dimensions: 59  x 119 x 45 mm
• Weight: 140 gr
• Color: Blue (active electronics)

What Problems Does the GB Solve?

The Problem: Poor Input Buffers in Modern Devices

Most mainstream guitar effects processors, digital pedalboards, and multi-effects units have compromised input stages to reduce cost and complexity. These devices typically present input impedances of 100 kΩ–1 MΩ—far lower than the 4–10 MΩ ideal for guitar pickups.

When you connect a passive guitar directly to these devices:

1. Loading effects: The device loads your guitar’s high-impedance signal, causing progressive high-frequency rolloff (the “cable-loss” effect even without long cables)

2. Tone dulling: The top-end sparkle, attack clarity, and harmonic definition disappear

3. Impedance mismatch: Your guitar’s 5–15 kΩ source impedance meets the device’s 100–1000 kΩ input impedance, creating a mismatch that emphasizes certain frequencies and suppresses others

4. Cumulative degradation: When using multiple effects or connected to another system, the problem compounds

Professional audio devices use high-impedance input buffers (>4 MΩ) precisely to avoid this problem. The GB brings this professional-grade input buffering to your guitar setup.

The Solution: Professional-Grade Input Buffering

The GB connects between your guitar and any effects processor, pedalboard, or audio interface. Its J-FET input stage:

• Presents ≥4 MΩ input impedance to your guitar—the ideal load for passive pickups

• Converts the signal from high-impedance to low-impedance (<1 kΩ output impedance)

• Delivers a “strong” signal to your effects processor or pedalboard that is immune to their input impedance issues

• Maintains unity gain (0 dB) and transparent sound (THD <0.002%)

After the GB, your signal no longer depends on the quality of the receiving device’s input buffer. You control the signal chain instead of the device’s shortcomings controlling your tone.

Connection and Use

Connection Path:

 

Input: Standard 1/4″ TS jack (unbalanced, same as your guitar cable)
Output: Standard 1/4″ TS jack (unbalanced, standard guitar cable)
Power: 5.2mm barrel jack, center-positive, 9–24V DC

Important: Center-positive, negative outside polarity (opposite of typical boss-style pedal power). Use only power supplies with this polarity specification to avoid damaging the unit.

Why J-FET Input Stage?

The GB uses discrete J-FET transistors (the same technology in our professional J-series DI boxes) rather than operational amplifier ICs because:

1. Optimal impedance: J-FETs naturally present extremely high input impedance (≥4 MΩ) without additional circuitry

2. Natural sound: J-FET topology has been favored in high-end audio for decades because of its natural, transparent character

3. Low distortion: <0.002% THD—audibly transparent, below perceptibility threshold

4. Fast response: No overshoot or ringing on transients

5. Proven in professional audio: The same topology used in mastering-grade equipment

Recommended Applications

Effects Processor with Guitar

Digital multi-effects units and amp modeling processors typically have input impedances of 100–500 kΩ. The GB ensures your guitar’s signal remains bright, articulate, and responsive, compensating for the processor’s less-than-ideal input stage.

Large Pedalboard into Amp or Interface

Complex pedalboards with multiple true-bypass effects accumulate capacitive loading. The GB, placed at the input, provides the ideal interface between your guitar and the pedalboard chain.

Guitar into Audio Interface

Budget audio interfaces often have compromised instrument preamps. The GB provides a professional input stage that maintains tone integrity before recording.

Vintage or High-Output Pickups

Vintage single-coil pickups, low-impedance humbucker designs, and high-output variants benefit most from the GB’s exceptional input impedance specification. The high impedance ensures these pickups are never “loaded down.”

Long Cable Runs Before Effects

When your guitar is far from your effects processor (10+ feet), the GB placed immediately after the guitar compensates for cable capacitance and low-impedance loading.

Active Pickup Compensation

While active pickups have lower impedance than passive pickups, they still benefit from the GB’s low output impedance when feeding into effects devices with poor input buffers.

Power Supply

The GB requires an external DC power supply: +9V to +24V, 5.2mm barrel jack, center-positive (positive at tip, negative at sleeve).

Headroom increases with supply voltage:

• +9V: Standard operating voltage, suitable for most applications

• +12V: Recommended for hot pickups or devices with input levels that exceed +10 dBu

• +15V–24V: Maximum headroom for extreme applications

Compatible power supplies:

• Isolated DC power supplies with center-positive polarity

• Some single-output regulated power supplies (verify polarity before connecting)

⚠️ Important: Most “boss-style” pedalboard power supplies are center-negative. The GB requires center-positive. Using incorrect polarity will damage the unit. Why? Because ground must be on the chassis. Sorry, this is our statement, we do not support mainstream opinion.

Key Specifications Compared to Professional Audio Devices

The GB brings professional-grade input buffering specifications to unbalanced guitar signal paths.

What the GB Does NOT Have (And Why)

• No balanced XLR output: The GB is designed for unbalanced TS connections (guitar signal format). Balanced outputs require transformer isolation or dual op-amp differential circuitry unsuitable for unbalanced operation.

• No ground lift or pad: These features are for balanced audio and ground-loop management, which don’t apply to unbalanced guitar signal paths.

• No bypass switch: The GB is designed to be always active. Unity gain means it does nothing when off and nothing when on—it’s completely transparent. A bypass switch would be unnecessary complexity.

The GB is purposefully simple: a professional input stage for unbalanced guitar signals. Nothing more, nothing less.

How the GB Works: Signal Flow

 

Your guitar sees the ideal 4 MΩ load (no tone sucking). The effects processor receives a low-impedance signal that is immune to further loading.

The GB Advantage

For guitarist using professional effects processors or multiple pedalboards:

The GB eliminates the compromises typically required when connecting high-quality instruments to consumer-grade effects devices. It ensures that your tone remains in your hands, not at the mercy of the effects device’s input impedance budget.

One small investment delivers:

• No more dull tone when using effects

• No tone change when switching between devices

• Preserved attack clarity and high-frequency definition

• Professional-grade signal integrity in an unbalanced format

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Frequently Asked Questions

Q: Why does the GB improve my tone when effects processors should be transparent?
A: The GB doesn’t improve your tone—it stops degradation. Most processors have input stages that load your guitar’s high-impedance signal, causing high-frequency loss. The GB presents the ideal input impedance so the processor receives your full, uncompressed tone. The processor becomes transparent to your original signal instead of coloring it.

Q: What if my effects processor sounds fine without the GB?
A: Many modern processors are designed for line-level sources (keyboards, synthesizers) and compromise on guitar input buffering. You may not notice the degradation until you compare before/after with the GB, or until you use multiple effects where cumulative loading becomes obvious.

Q: Can I use the GB with active pickups?
A: Yes. Active pickups have lower impedance than passive pickups but still benefit from the GB’s optimized buffering. Use 12V power supply for maximum headroom.

Q: Do I need a separate power supply, or can I use a pedalboard power supply?
A: You need a dedicated power supply with center-positive polarity (opposite of typical pedal supplies). Standard boss-style 9V pedalboard power is center-negative and will damage the GB if connected.

Q: Where should I place the GB?
A: Immediately after your guitar, before any effects processor or pedalboard. The GB conditions your signal before it enters any device.

 

Q: Can I use the GB with other Simple Way Audio products?
A: Yes. The GB’s output can feed any input stage. It works well before DI boxes, mixing consoles, or other professional audio equipment.

Q: Does the GB add latency or introduce any delay?
A: No. The GB is purely analog with no digital processing. Signal passes through at the speed of electricity—imperceptible.

Q: Can I chain multiple GBs?
A: Not necessary. One GB is sufficient. Chaining multiple buffers adds unnecessary complexity without additional benefit.

Q: What’s the difference between the GB and a professional DI box?
A: The professional DI boxes (D1mini, J1mini, etc.) provide ground-lifted balanced XLR outputs for professional audio systems. The GB provides unbalanced TS output optimized for guitar signal chains and consumer devices. Both use the same professional J-FET input buffering technology.

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The GB Guitar Buffer: Professional input impedance for your instrument’s uncompromised tone.