Universal Audio OX Reactive Amp Attenuator with Speaker Modeling


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A More Flexible Way to Use Your Tube Amplifier

With the Universal Audio OX Amp Top Box, you can play your favorite tube amplifier at its sonic sweet spot at any volume level. And that's just the start — featuring UA's Dynamic Speaker modeling technology, you'll be able to access dozens of spot-on mic and guitar cabinet emulations. Premium analog components and one of the world's best reactive load circuits ensure you'll hear all the dynamics and harmonic complexity your amplifier has to offer. The OX Amp Top Box is a powerful solution for recording, allowing you to achieve those cranked-amp tube tones at any volume level. Many recording guitarists at Guitar World prefer this recording method for maximum sonic control. Instead of a speaker cabinet, plug your tube amp into the Universal Audio OX Amp Top Box to explore a whole new range of tonal possibilities.


Reactive load circuit for realistic speaker response

Universal Audio claims OX features the best reactive load circuit in the world, allowing you to crank up your amp for harmonically-rich tone while keeping volume at practical levels. Reactive load circuits respond to your amp's signal the same way a real speaker cabinet would. That means you'll hear — and feel — all the sonic nuance and harmonic complexity your amplifier has to offer, even when you're playing at neighbor-friendly volumes. Or even through headphones. You'll feel like you're playing through a real speaker cabinet because the reactive load responds the same way — and Guitar World is sure that will inform your playing for the better.

Accurate speaker breakup and cone cry sets OX apart

Because OX is a reactive load box, it responds in a complex and non-linear fashion to the signal you're sending it from your amp — just like a real speaker cabinet does. That means you can achieve realistic "cone cry," which is the generation of additional harmonics in a speaker cone that occurs only at certain frequencies and volume levels. And you'll hear lifelike speaker breakup as you crank your amplifier, even when OX is keeping the volume at bedroom levels. Not only will you hear these sonically-sweet complexities, you'll feel them as OX responds to the nuances of your personal playing style.

The ultimate recording tool for guitarists?

With dozens of microphone and guitar cabinet emulations to choose from, OX offers a ton of flexibility in the studio. It's like having a world-class microphone placed in the perfect position in front of a premium speaker cabinet, in a great-sounding studio space. Except you don't have to set up a mic, manage acoustic reflections, fight noise, and so on. Just plug in your amplifier of choice, use the Rig control to explore mic and cab combinations, and you're ready to record with stellar tone at any volume level.

Remote control over Wi-Fi with app for desktop and mobile

With the OX app for your computer or mobile device, you have full control over OX's parameters from your local Wi-Fi network. Access key parameters, change mic and cabinet combinations, and much more, from anywhere within Wi-Fi range. Don’t want to carry a computer or iPad to the gig? No problem! UA allows you to load 6 full rigs to the front panel selection switch so you can change from a small combo to a full stack with just a twist. This includes every single, tweaky parameter available within OX’s huge range of control.

Universal Audio OX Amp Top Box Features:

  • Reactive load box for tube amplifiers with built-in speaker emulation
  • Dynamic Speaker modeling emulates the nuanced behavior of real moving speakers
  • Access dozens of mic and guitar cabinet models
  • Allows you to achieve cranked-amp tones at any volume level
  • "Rig" controls elects six customizable mic/cab/FX combinations
  • "Room" controls the ambient room sound of the Rig emulation
  • Footswitch input for additional control options
  • Selectable 4-, 8-, or 16-ohm operation
  • Built-in EQ, compression, delay, and reverb effects
  • Headphone output for silent practice
  • Balanced line outputs and S/PDIF digital output for recording
  • Use OX mobile/desktop apps over Wi-Fi for remote control