Universal Audio - OX Amp Stomb Box
Get Legendary Studio Tones from your Tube Amp — Anywhere, at Any Volume.
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Play and record your tube amp in its tonal sweet spot — anywhere, at any volume, with full dynamics
Get stunning mic and guitar cabinet combinations at the turn of a RIG knob — no miking required

Audition, tweak, and save more than 100 jaw-dropping custom Rigs from compatible iPad, or Mac/Windows computers.
Get authentic “edge of destruction” sounds, complete with UA Dynamic Room Modeling, speaker breakup, and cone cry

The World’s Best Reactive Load Box
With decades of analog hardware engineering expertise, Universal Audio’s dream team of engineers set out to design a reactive load box that retains the tone, dynamics, and feel of your tube amp — no matter how much it’s attenuated. The goal was for your tube amp to “see” OX as an actual speaker — with continuously variable impedance and response — so you don’t lose a drop of tone or playing dynamics.
A Complete Guitar Recording System
OX’s front-panel, six-position RIG control allows you to quickly choose from complete setups — including emulated speaker cabinets, close mics, ambient room mics, and up to four simultaneous studio effects. OX is also the only guitar recording system to offer a complete selection of expertly placed room mics, giving you the authentic experience of pushing air while recording your cranked amp in a world-class tracking room.
Dynamic Speaker Modeling
UA’s groundbreaking Dynamic Speaker Modeling faithfully emulates speaker breakup, drive, and cone cry — an essential ingredient to authentic tube amp tones. Using the Speaker Breakup knob in the OX app, you can control the harmonics and sonic complexity that occurs only at certain frequencies and volume levels on various speakers — far beyond a static Impulse Response system — giving you the same sonic phenomenon that occurs with a real speaker cabinet.

All The Right Connections
Not only does OX Amp Top Box feature a front-panel headphone jack for silent practice with your cranked tube amp, it also sports a bevy of connections for all kinds of recording and live workflows. Stereo S/PDIF digital outputs via RCA and optical TOSLINK, as well as balanced TRS stereo line outputs with front panel level control, give you the necessary connections for studio monitors, DAW, or live mixing console inputs. Plus, you can connect any one, two, or three-button footswitch and toggle OX's studio-quality effects on and off.
A Beautiful Software App
Most guitar products do digital awkwardly. They’re ugly and hard to understand. The OX software app, on the other hand, offers slick, intuitive control over all of OX’s RIG settings via Wi-Fi — letting you tweak, store and recall hundreds of presets from your iPad, Mac, or Windows 10 computer. You can then save your six favorite tones onto OX’s front-panel RIG knob for instant recall in the studio or at a gig. https://youtu.be/OGxQ_0u6uLw| SYSTEM | I/O Complement |
| Amplifier Input One | |
| Speaker Output One | |
| Line Outputs Two (one stereo left/right) | |
| Headphone Output One (stereo left/right) | |
| Digital Outputs Two (mirrored) | |
| ANALOG I/O | |
| Amplifier Input | Connector Type ¼” Female TS Unbalanced |
| Input Impedance 4/8/16 Ohms (selectable) | |
| Maximum Input Power 150 Watts RMS, 200 Watts peak | |
| Safety Load (power off) 16 Ohms | |
| Speaker Output | Connector Type ¼” Female TS Unbalanced |
| Output Attenuation Five Attenuation Steps and Speaker Off | |
| Output Latency None (pure analog) | |
| Line Outputs 1 – 2 | Connector Type ¼” Female TRS Balanced |
| Dynamic Range 114.5 dB (A-weighted) | |
| Frequency Response 20 Hz – 20 kHz, ±0.1 dB | |
| Signal-to-Noise Ratio 114.0 dB (A-weighted) | |
| Total Harmonic Distortion + Noise -110 dB @ -3 dBFS | |
| Channel Separation 129 dB | |
| Output Impedance 100 Ohms | |
| Maximum Output Level 20.2 dBu (balanced) | |
| Output Latency 2.77 milliseconds (122 samples @ 44.1 kHz) | |
| Stereo Headphone Outputs | Connector Type ¼” Female TRS Stereo |
| Dynamic Range 113.0 dB (A-weighted) | |
| Frequency Response 20 Hz – 20 kHz, ±0.1 dB | |
| Signal-to-Noise Ratio 113.0 dB (A-weighted) | |
| Total Harmonic Distortion + Noise -107 dB @ -3 dBFS | |
| Maximum Output Power 80 milliwatts into 600 Ohms | |
| Output Latency 2.77 milliseconds (122 samples @ 44.1 kHz) | |
| DIGITAL OUTPUTS | Format S/PDIF IEC958 |
| Connector Type 1 Female Phono (RCA) | |
| Connector Type 2 Optical TOSLINK JIS F05 | |
| Sample Rate & Bit Depth 44.1 kHz, 24-bit | |
| Output Latency 2.57 milliseconds (113 samples @ 44.1 kHz) | |
| ELECTRICAL | Power Supply External AC to DC Power Supply, Level VI compliant |
| AC Input Connector Type IEC Male | |
| AC Requirements 100V – 240V AC, 50 – 60 Hz | |
| DC Connector Type XLR 4-Pin Locking Male (Neutrik P/N NC4MDM3-H) | |
| DC Requirements 12 VDC ±5%, 1.5A | |
| Maximum Power Consumption 18 Watts | |
| Operating Temperature Range 32° to 104° Fahrenheit (0° to 40° Celsius) | |
| Storage Temperature Range –40° to 176° Fahrenheit (–40° to 80° Celsius) | |
| Operating Humidity Range 10% – 95%, non-condensing | |
| COMPLIANCE | EMC and Safety Standards |
| FCC Part 15 for Class B digital device EN 610003-3-3:2013 EN 301489-17 | |
| ICES-003 EN 55103-2 KN 301489-1 | |
| VCCI-CISPR 32:2016 KN32 KN 301489-17 | |
| EN 55032 KN35 UL/cUL 62368-1 | |
| CIPSR 32:2012 CNS 13438 EN 62368-1 | |
| EN 61000-3-2:2014 EN 301489-1 IEC 62368-1 | |
| PHYSICAL | |
| Dimensions | Width 15.01 in / 381.25 mm |
| Height, Chassis Only 4.45 in / 112.94 mm | |
| Height, Including Rubber Feet 5.45 in / 138.44 mm | |
| Depth, Chassis Only 8.05 in / 204.5 mm | |
| Depth, Including Knob & Jack Protrusions 9.04 in / 229.58 mm | |
| Shipping Box (Width x Depth x Height) 20 3/4” x 12 15/16” x 11 5/16” | |
| (52.7 cm x 32.9 cm x 28.7 cm) | |
| Weight | Weight (unit only) 14.1 Lbs / 6.40 Kg |
| Package Contents | OX Amp Top Box Unit |
| External Power Supply | |
| IEC Power Cable — US, EU, or UK (region dependent) | |
| Quick Start Guide | |
| RIG Control Presets | |
| Safety & License Sheet |
Universal Audio
AUTHORIZED DEALERAvailable in store & online — Nantel Musique
Universal Audio is one of the most recognized names in musical instruments worldwide. Known for exceptional build quality, innovative design, and reliable performance across every price range, Universal Audio instruments are trusted by beginners and touring professionals alike.
at nantel musique, we carry a curated selection of universal audio effects & pedals — each one inspected, set up, and backed by our expert team. every purchase includes our satisfaction guarantee and dedicated after-sales support.




