United Studio Technologies Replay Box – Professional dual-transformer reamping interface
The United Studio Technologies Replay Box represents the ultimate achievement in professional reamping design. Engineered for audio engineers, producers, sound designers, and high-end studios, this unit delivers exceptionally low noise, unmatched passive gain capability, and two fully independent circuits offering two highly refined tonal characters: Transparent and Harmonic.
The result of more than 20 years of experimentation and real-world feedback from top industry engineers, the Replay Box eliminates the common compromises of noise and insufficient gain found in most reamp boxes. With its meticulously engineered internal layout, exemplary isolation, and rugged chassis designed for both studio and touring, it stands as the new modern standard for professional reamping.
Two Independent Circuits – Two Distinct Sonic Personalities
The Replay Box features two completely independent reamping paths:
● Transparent Mode: Equipped with the custom-wound 5043 transformer (USA). This circuit delivers exceptional signal purity, unmatched isolation, and mastering-grade accuracy. With its passive gain of approx. +3 dB, it maintains complete signal integrity while enhancing presence — without any active components or unwanted coloration.
● Harmonic Mode: Features an alternative transformer designed to add density, character, and warmth. It enhances low and low-mid richness, softens extreme highs, and introduces a subtle, musical harmonic saturation — ideal for guitar amps, creative distortion, sound design, and more colored reamping applications.
The Cleanest Passive Gain Ever Achieved in a Reamping Box
The Replay Box solves the two recurring issues in reamping: noise and insufficient gain. While other boxes introduce distortion, hiss, or require an additional pedal (which adds more noise), the Replay Box provides all the gain you need directly from its oversized transformers, combined with true ground isolation to eliminate any hum from ground loops.
The result: powerful, clean, dynamic, and completely reliable performance — even with the most demanding amplifiers.
A Design Proven by Professional Engineers
Before its official release, the Replay Box was already circulating in elite studios, used as a secret weapon by well-known engineers. Its design directly descends from the first custom, hand-built units created by Chad Kelly, now refined and industrialized by United Studio Technologies.
Its reinforced aluminum chassis, recessed design, and removable threaded feet ensure maximum durability for both studio and touring environments. It integrates seamlessly into any professional setup thanks to its flexible mounting options and robust ergonomics.
Technical Specifications:
- Input impedance: Transparent: 300 Ω / Harmonic: 50 Ω
- Output impedance: Transparent: 1 kΩ / Harmonic: 150 Ω
- Frequency response: Transparent: 20 Hz – 20 kHz ±0.5 dB / Harmonic: 40 Hz – 20 kHz ±0.5 dB
- Output gain: Transparent: +3 dB / Harmonic: +5 dB above input level
- Recommended input level: +4 dB balanced line level
- Transformers: Custom 5043 (Transparent) + dedicated Harmonic transformer
- Auxiliary controls: Phase Invert, Ground Lift
- Dimensions: H 52 mm (with feet) / 46 mm (without feet) – W 149 mm – D 155 mm
- Weight: 0.8 kg
- Chassis: Reinforced aluminum, recessed design
Key Points:
- Dual independent circuits: Transparent (clean) and Harmonic (colored).
- Custom USA-wound transformers for clean, powerful passive gain.
- True ground isolation eliminates all ground-loop hum.
- Ultra-high passive output capability: no external pedals or boosters required.
- Premium reamping performance: clean, dynamic, and studio-grade signal control.
- Rugged aluminum chassis built for studio and touring use.
- Industry-proven design long before commercial release.
