• Premium, no-compromise analog reactive load box and guitar system for tube guitar amps.
• Instant album-quality mic and speaker cabinet tones via front-panel RIG control.
• Get record-ready sounds quickly with expertly-placed virtual mics and cabs - no amp miking required.
• Five finely-tuned guitar amp attenuation levels, from completely silent to whisper quiet to full band volume.
• UA Dynamic Speaker Modeling emulates speaker drive, breakup and cone cry.

Get Legendary Studio Tones from your Tube Amp — Anywhere, at Any Volume. OX Amp Top Box is a premium reactive load box and guitar system that gives you perfectly studio-miked amp sounds from your favorite tube amp. OX lets you play and record your amp in its sweet spots — from huge clean tones and edge-of-breakup to fully cranked — at any volume level, and with mic, room, and speaker cabinet emulations at the turn of a knob. Featuring Universal Audio’s breakthrough Dynamic Speaker Modeling, OX is the first system to accurately emulate speaker drive, breakup, and cone cry — making it the world’s finest speaker attenuator and guitar amp solution. 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. Just plug your tube amp’s speaker output into OX, and then plug OX’s output into your cabinet, and you’ll enjoy your amp’s natural tone like never before. OX is more than a reactive load box, it's a complete Guitar System. OX's front-panel, six-position RIG control allows you to quickly choose from complete setups — including 22 vintage and modern cabinets loaded with iconic speakers from Celestion, Jensen, JBL, and more close mics, ambient room mics, and up to four simultaneous studio effects. OX is also the only guitar system to offer a complete selection of expertly placed room mics, giving you the authentic experience of pushing air while your cranked amp in a world-class tracking room. Dynamic Speaker Modeling A's groundbreaking Dynamic Speaker Modeling faithfully emulates speaker breakup, drive, and cone cry — an essential ingredient to 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. Most guitar products do digital awkwardly; they’re ugly and hard to understand. The OX software app, on the other hand, offers simple, 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 sounds onto OX’s front-panel RIG knob for instant recall in the studio or at a gig. OX Amp Top Box also features a front-panel headphone jack for silent practice with your cranked tube amp, and sports a bevy of connections for all kinds of and live workflows. S/PDIF RCA and optical TOSLINK digital stereo outputs, 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.