Introducing the Replay Box — the new benchmark in reamplification. The United Technologies Replay Box delivers exceptional performance and versatility for re-amping. Whether you’re working with detail-obsessed artists or exploring new sound design possibilities. Replay Box gives you ultra-quiet operation, flexible voicing, and the kind of clean gain that takes your workflow further. With two custom transformer circuits and plenty of output on tap, Replay Box sets a new standard for recordists.

Two transformers. Two distinct voicings.

Replay Box features two independent reamplification circuits: Transparent and Harmonic.

Transparent

The Transparent circuit uses our custom-wound, US-made 5043 step-up transformer. This delivers outstanding signal isolation and noise rejection for mastering-grade performance. It accepts balanced or unbalanced line-level input and produces a clean, isolated, unbalanced output. It can drive any amp, pedal, or processor. Because the transformer is passively wound for gain. it provides an additional 3 dB of headroom above the already +4 dB-rated input from your DAW or recorder. With no active circuitry or extra components in the path, Transparent delivers the cleanest gain available in a reamplification device.

Harmonic

Harmonic mode is designed for players and engineers who want a little more color and thickness in the re-amp stage. It switches to a different transformer specifically voiced to add character, with a steeper gain ratio and a gentle roll-off in the highest frequencies. The result is subtle harmonic and phase distortion in the sub-bass range, adding weight to the low mids and creating a warmer, more aggressive tone.

Pure transformer gain, with the headroom you need

Replay Box was built to solve the two biggest re-amping challenges: noise and insufficient gain. When you re-amp, any unwanted noise in the signal gets amplified along with the performance. Unfortunately, many re-amp boxes add their own noise and coloration, making it harder to achieve clean, usable results. Because many units don’t provide enough gain to properly drive an amp, engineers often have to rely on boost pedals or preamps. These pedals or preamps can introduce even more noise, distortion, and unwanted character. Replay Box solves both problems. It delivers more clean gain than you’ll likely ever need, without requiring a noise-prone boost or preamp pedal. True ground isolation also helps eliminate ground-loop hum, keeping your re-amping chain quiet and reliable.

Proven in the field before launch

Replay Box is the result of more than two decades of experimentation and feedback from early users of Chad Kelly’s handmade reamplification boxes. These early units became trusted tools for top engineers, and their real-world input helped shape every detail of the final design. And while the internal engineering is the star of the show, the Replay Box is also built to survive the realities of studio and stage use. Its recessed aluminum chassis helps protect it from accidents, while the screw-mounted removable feet make it easy to adapt to different mounting needs. Backed by more than 50 years of combined industry experience, United Technologies created Replay Box to bring two highly respected boutique re-amp voices together in one enclosure.

Don’t forget to take a look at our other United Studio Technologies products!

Visit the United Technologies website for more info.