The Essentials to Know About the Universal Audio OX Amp Top Box Loadbox
- Play your tube amp at its sweet spot (clean, edge of breakup, heavy crunch) at controlled volume, up to silent mode.
- High-end reactive analog loadbox: your amp "sees" a realistic load to preserve attack, dynamics, and feel.
- Recording-ready sound thanks to virtual cabinets, microphones, and rooms, plus built-in Universal Audio studio effects (EQ, compression, delay, reverb).
- Immediate and deep control: 6-position RIG selector on the front panel + OX app via Wi-Fi for editing and saving presets (iPad, macOS, Windows 10).
"Cabinet cranked up"... without volume constraints
The sound of a tube amp "in the zone" has always come as much from the amp as from the cabinet, which compresses, resonates, and saturates musically. The OX Amp Top Box follows this tradition by combining studio-style attenuation with a modern recording approach: you get the grain and response of a well-driven amp while enjoying a consistent and reproducible mic'd sound without depending on the room, mic placement, or uncontrollable volume.
Who is it for, what styles, and in which contexts?
OX is designed for guitarists playing tube amps who want to preserve the "feel": from blues to rock, hard rock to metal, and even ambient sounds when using room mics and reverb. At home, it becomes a premium solution for silent practice with headphones and recording authentic amp tones late at night. In the studio, it speeds up tracking with instantly usable cabinet and mic setups. Live, its line and digital outputs simplify sending to a mixing console while keeping your amp as the drive source.
Controls, modeling, and connectivity: everything designed for speed
On the front panel, the RIG selector instantly recalls 6 complete configurations: cabinet, close mic(s), room mic(s), and up to four simultaneous effects. The OX app via Wi-Fi allows much deeper editing: choice of cabinets, microphones, room settings (Dynamic Room Modeling), and control of Speaker Breakup to shape the speaker "working" feel. For integration, OX offers balanced stereo line outputs on 6.35mm TRS jacks, S/PDIF digital outputs (RCA and TOSLINK optical), a front panel headphone output, and a footswitch input for effect control.
Sound
OX's strength lies in its realistic response: crisp attack, natural compression, and the sensation of the cabinet singing as the amp heats up. The result remains focused on your amp's character (fairly transparent to the core), while adding a "studio" finish with solid recorded tones. Between a nervous edge of breakup and thick saturations, you get a livelier result than a simple impulse response approach, with a very convincing sense of air and depth.
Technical Specifications
Type and Usage
- Reactive loadbox / analog attenuator for tube guitar amps
- Five levels of cabinet output attenuation, from silent to very quiet, up to band volume playing
- Power handling: 150 W RMS (max)
Processing and Modeling
- RIG control: instant selection of 6 cabinet + mic + room combinations with processing
- UA "Dynamic Speaker Modeling" technology: dynamic behavior of modeled cabinets according to gain (compression, resonance, breakup)
- Room recreation for mic placement (Dynamic Room Modeling)
- Built-in Universal Audio effects: EQ, compression, delay, reverb
- Choice of vintage and modern recording microphones
Impedance
- Impedance selection: 4, 8, or 16 ohms
Connectivity
- Front panel headphone output
- Balanced stereo line outputs on 6.35mm TRS jacks
- Stereo S/PDIF digital outputs (RCA and TOSLINK optical)
- Footswitch input for connecting a control pedal
- OX mobile or desktop app via Wi-Fi: full editing and preset saving
Dimensions and Weight
- Dimensions: 381 x 230 x 138 mm
- Weight: 6.40 kg
Included Accessories
- Box and documentation
- External power supply (depending on package) and IEC power cable (depending on region)
Power Consumption
- Power supply required: 12 V DC
- Current required: 1500 mA
- Maximum consumption: 18 W