UAD Spark: Get 20+ of the best UAD plug-ins for a low monthly price. Learn More ›

Get up to $300 off OX Amp Top Box. Ends 3/31. Find a dealer ›

Get Legendary Studio Tones from your Tube Amp — Anywhere, at Any Volume.

OX is a premium reactive load box and guitar recording system, giving 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 recording solution.

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

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

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

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

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

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.

Watch The Reviews


      Premium, no-compromise analog reactive load box and guitar recording 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

      World-class Universal Audio EQ, compression, delay, and reverb effects built-in

      Selectable 4, 8, and 16-ohm operation

      Front-panel Headphone out for silent practice with cranked tones

      Balanced TRS line outs and S/PDIF digital outs for stereo recording

      Pair with the OX mobile or desktop app over Wi-Fi for editing and saving RIG presets

      Footswitchable control of OX's studio-quality effects

      OX App Requirements

      OX Amp Top Box

      2.4 GHz Wi-Fi network with internet connection to register (once only)

      (iPad) iOS 12 or iPadOS 13

      (Mac) macOS Mojave or Catalina

      (Win) Windows 10 64-Bit Edition

      Customer Reviews

      OX Amp Top Box

      Overall Rating

      B. Windel

      February 3, 2023

      I LOVE this thing.

      What a game changer. I have this connected to my Apollo via the optical connection and it sounds SO good. Love it. Being able to use my pedal board + 3 amps and yet keep it all contained in either my headphones or nearfields is just a beautiful thing. The power soak / attenuator bit is great too, don't get me wrong, but I don't use it as much. The desktop app on macOS works great - no issues whatsoever.

      T. Limbeck

      January 22, 2023

      Could be 5 stars, but UA has abandoned support for OX

      The iPad app is long overdue for an update to run in landscape mode or be compatible with multitasking features in iPadOS. Intermittent connection issues have always been a problem with the onboard WI-FI. An update to utilize the rear USB ports for connectivity would solve many of these issues. At this point I regret not purchasing a Kemper and sticking with my old Marshall Power Brake instead

      E. Myers

      January 17, 2023

      What took me so long?

      This thing absolutely rules. Messed around a little with the app which was cool but have just been spending my tube with the director cabinet emulation on the unit straight to speaker. And to be honest it hasn’t left the first rig setting at all. I look forward to the ride.

      k. kim

      December 14, 2022

      경쟁자가 없습니다

      출시한지 시간이 꽤 지났음에도 불구하고 경쟁자가 없습니다
      잠자고 있던 앰프 헤드를 잘 사용 할 수 있게 되었습니다
      최고의 제품이며 추후 펌웨어 업데이트 혹은 새로운 버전의 하드웨어 역시 기대하게 만드는 UA의 기술력에 찬사를 보냅니다

      R. Derman

      November 26, 2022

      Technically challenged!

      I'm sure this is a great product because everyone's raving about it! I found the manual very hard to follow and not terribly helpful. I can't figure out how to record the Ox into Cubase 10. If anyone who reads this is interested, I would gladly pay for a 30 minute support call over Zoom. Contact: or Whatsapp: +491623847955 thanks, Rick

      I. Townsend

      November 7, 2022

      OX Box is the top guitar experience!!

      The OX Box is a beautiful experience just out of the box! It have the most lush guitar sounds that are unbelievable. Just amazing… Thank Universal

      W. Marshall

      November 1, 2022

      The OX Box surpassed my expectations!

      As a working guitarist I was well aware of the OX's capabilities in handling high-powered overdriven tube amps like vintage Marshalls and boutique amps like Soldanos and Dumbles and making them more manageable at loud levels in the studio. However, I wasn't sure of how they would respond to a clean full jazz tone with an archtop hollow body. Well, I was pleasantly surpised when I hooked the OX up to my blackface Fender Twin Reverb with a 1963 Gibson L5CES. Fantastic! Warm and fat with plenty of response...I rely on the sound and feel of my stage level at about 5-6 but that is not normally possible when I do my online videos and prefer to have the amp nearby. The OX more than solved my problem and mated beautifully with my Apollo Twin interface straight into OBS for video recording and Logic Pro for audio tracks. Bravo, Universal Audio! Another triumph.

      P. Zoltan

      October 29, 2022

      It's amazing when it's connected

      4 hours into a recording session. Still trying to connect the OX to the PC. Even uninstalled the antivirus... so after 23 restarts, two factory resets, and 2 flash drive firmware updates, I am still trying to find my ox while researching the fastest ways to commit suicide :-)

      P. Giacalone

      October 28, 2022

      Great tool!

      I recently had to relocate my studio from a very large space to a very small one, and as such I now rely on the OX for recording. The design is fantastic. and the bottom line is it does what it supposed to do. I'm able to use all of my amplifiers and get my work done.

      that's said, The cabinet emulations don't have the dimension of recording real cabinets, but neither does any other solution i've seen for cabinet simulation. I think we're in the infancy of this technology. I hope UA will strive to improve the quality and continue updating. I love the fact that when I get back to a larger space it will still be useful as a power soak, or even direct recording when it's convenient.

      Would love to see some Leslie sims added.

      Overall great product!

      E. Bressler

      October 26, 2022


      Sounds amazing with so many choices, why didn’t I do sooner!

      P. Freudenberg

      October 22, 2022

      Loving My Ox

      For the benefit of consistent recording (and to promote domestic harmony), I evaluated many electric guitar recording options and all paths lead to Ox. Great tones are easily achieved with this system. There is a wide and diverse palette of sonic options. I found the interface intuitive and easy to operate.
      The packaging is also top-notch. This beast can really hold up.

      Would love to see the following enhancements:

      * Bass Rigs
      * Moveable mic positions
      * 1176 for individual mic processing - perhaps alternate comp/limiters as well
      * Alternate reverbs to plate (chamber, room, hall)
      * Envelope modulation option on delay (think PCM41)
      * Direct Outputs of individual "mics"

      A. Duffield

      October 13, 2022

      Very convenient but......

      I have been using some form of attenuator on my vintage Marshalls since 1980.....inspired by Tom Scholz, I had my local guitar shop build a big pot in a metal enclusure that I stuck between the amp and cab. Over time that gave way to Marshall Powerbrakes, Kock Load Box 120 and, most recently Aracom's (of the units I have tried, these were the best at maintaining tone but giving flexibility in impedance and level - both line and through the cab). For recording I have alwatys used mics but found them frustrating nad my results inconsistent - recenlty I bought a Tul G12 that massively improved the challenge and made life coparatively simple....apart from the fact that you still need to crank the amp to levels that are not always neighbour friendly when recording at home. I tried a few cab sims and really liked the ADA unit hooked up to the line level output of the Aracom but wanted something that had more choice for different amps and was introduced to the OX .

      Impressiosn to date are, on th ewhole, positive. I like the ability to plug into a single box and send separate feeds to the cab, to line level (mixer) and headphones.

      My only compliant is that the level control to the cab is stepped and at full level still seems attenuated. At lower levels there is definitely a loss of high end and clarity. In this respect the Aracom is superior IMO

      The strength of the OX (at least IMO) lies in the cab emulations whcih has huge choice, not just in enclosure/driver combinations but in the tools to manipulate the sound (mics, speaker break up, mic position, Eq, compression, delay, reverb).I have found it very simple to customise cabs and tailor solutions for different amps/guitars/tones and mixes.)

      My only complaint on the mic position is the choice limit to on or off axis. The ADA cab sim has a rotary control that allows a wider freedom of choice and I found this abilito to fine tune position a real advantage.

      I do not work in a DAW ( I have an old Soundcraft analogue desk and Otari Radar) so have little experience of other interfaces, IR or other similar products but saw a number of early OX reviews that were critical becuase it did not appear to offer compatibility with the reviewers preferred or chosen IR/sim package. Whilst I can understand that frustration, I have found no lack of choice in the OX and the available tools certainly enable the user to craft solutions to their own tastes/needs.

      I would like to see some additional bass cab options - I currently use a Darkglass B7K to record bass - but ot woul be great to see what OX could do with some more bass oriented emulations.

      Overall, happy to recommend the OX - has made life very simple and the "next level" suggestions I have do not prevent OX providing a very convenient and easy to use solution.

      H. Cho

      September 21, 2022

      It's good but

      please 48
      please room out separately
      please keep connect with app.

      R. Jamison

      August 28, 2022

      OX is a beast!!

      Using the OX with Marshall, Splawn, Mesa Boogie and Bad Cat amps. The OX does a decent job at attenuation but where it shows it’s true worth is direct or even better, thru headphones. With the available cabinets, mics and the ability to mix those at various levels gives you the ability to get practically any tone you are after. Updating with more cabinet models or the ability to download available IR’s would make this the ultimate amp/recording tool.

      H. Ohl

      August 10, 2022

      Great product - software needs updates

      After recording and releasing our new song (Friends by Frances & Johnny) which was recorded digital, I was searching for a more "living tone". I tried the OX with some old tube amps, Fender Blues Junior, Marshall JCM 800 and a Mesa Boogie and was totally blown away. I love the sound of the OX. Only the software has to be updated. I use a iPad and it would be great, if the app would be also in landscape mode. Also an iPhone App would be great and firmware updates... :-)

      P. Abed

      July 15, 2022

      Attenuator needs fix - and updates. Needed

      Just a checking, about to buy my second unit. The attenuator is impacting my tone, would be great to find a way to bypass the attenuator - just to have the option. Also, when can we expect the next update? I keep hearing this product has been shelved, and we shouldn’t be hopeful for updates.

      J. Skrivanek

      June 11, 2022

      Satisfied customer

      The opportunity to record with UA OX completely turned my current musical life upside down. I started with Captor and after three months I switched to OX - I still can't get enough of the sounds of my tube amplifiers at home with OX. You can listen to how it plays here: Good job at Universal Audio! Greetings from the Czech Republic.

      S. Saied

      May 6, 2022

      Wonderful Ox

      I can final let my amp breathe without going deaf or to jail! Love this thing. Quality is unmatched and the emulated cabinets, mics and effects are astounding.

      K. Haavik

      April 26, 2022

      Sounds Epic-

      Z. Drummond

      April 11, 2022

      An amazing unit

      I've been using mine for about a year. Love the versatility, and consistency. The sound I'm able to get from the ox with my amp is better that 90% of the mic'ed tones I can get live. The AC30 cabinet is exquisitely modeled. The only things holding the ox back in my eyes are the lack of midi, and a Hiwatt cab with Fane speakers.