Save up to 60% storewide in The UAD Half-Yearly Sale! Ends June 30th! Shop Now ›

OX Amp Top Box

OX Amp Top Box

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.

Now You Can:

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

      T. Schuster

      May 20, 2021

      Packed back up the same night it arrived.

      What is up with the microphonics coming from my tube amp? That is not normal. It’s not ok. And even if it was….how am I suppose to use this to record?! What if I wanted to mic my cab and mix that room tone with the modeled guitar tone? UA…you need to go back to the drawing board with this thing. I even considered getting out my scope and meters and opening up the OX to figure out WTF is going on and how to fix it. But you know what? I didn’t spend $1300 for a mod project. If UA wants to pay me $50/hr, I’ll figure out a solution. I’m not doing it for free and I won’t be paying $1300 for a product that is still under development.

      N. Lloyd

      May 19, 2021


      I’ve been a big fan of UAD products for a long time now.....I bought the very first UAD PCI cards probably about 20 years ago.....that’s crazy!!!!!
      Anyway.....I’ve got terrible tinnitus from a long career in bands and studios, so loud guitar amps are really not what I want to be near anymore.....
      This Ox Box is a game changer. Took a while to figure it out......I never read the manual so that’s probably why.
      Why has it got USB ports in the back? The seem to do nothing.
      Apart from that, it sounds amazing.
      Better results than I get with cabs and it’s silent. Awesome.
      10/10 UAD. Love it.

      N. Lloyd

      May 19, 2021


      I’ve been a big fan of UAD products for a long time now.....I bought the very first UAD PCI cards probably about 20 years ago.....that’s crazy!!!!!
      Anyway.....I’ve got terrible tinnitus from a long career in bands and studios, so loud guitar amps are really not what I want to be near anymore.....
      This Ox Box is a game changer. Took a while to figure it out......I never read the manual so that’s probably why.
      Why has it got USB ports in the back? The seem to do nothing.
      Apart from that, it sounds amazing.
      Better results than I get with cabs and it’s silent. Awesome.
      10/10 UAD. Love it.

      G. Heath

      May 14, 2021

      Had high hopes for this, especially at the price.

      So I bought an OX a couple of months back and thought I'd get used to it before I formed any opinion of it. I have a lot of UAD gear and plug ins and this is not in the same league.
      On paper a great piece of kit, BUT it distorts clean sounds on the first 3 attenuation settings, and to my ears has a distinct piezo type quack through headphones. It's more pronounced on IEM cans, less so on decent over ears but still there. Using distortion channels it's not noticeable or lost. I have several decent amps and it does it with all of them, so I'm distinctly underwhelmed for £1050.
      It's been suggested I use a compressor before my guitar hits the amp, but that kinda defeats the purpose I just want my clean amp sound attenuated, not clipped.
      I'm not the only person to complain about this problem there are literally dozens of posts on forums about this, so hoping UAD can do some sort of Firmware update that addresses this.

      b. janzen

      May 7, 2021

      firmware? more like nowhere

      Hope you saved your flashdrives from 2005 cause this sonnabitch can't be updated unless your flash drive is less than 2GB!
      Currently digging up grandmas grave to grab her last flash drive so I can try to make this work in 2021.

      b. janzen

      May 7, 2021

      firmware? more like nowhere

      Hope you saved your flashdrives from 2005 cause this sonnabitch can't be updated unless your flash drive is less than 2GB!
      Currently digging up grandmas grave to grab her last flash drive so I can try to make this work in 2021.

      b. janzen

      May 7, 2021

      ox box sux

      more like sux box ammirite

      A. Barker

      April 13, 2021

      Best tool for Home Studio guitar tone!

      I’ve had all the other speaker sim reactive load boxes... and to me the OX sounds and feels at least twice as better when I compared my then current favorite loadbox. I spend much more time grooving good tones than tweaking also, but even when tweaking Ox, it’s a fun tweak.

      R. Park

      April 13, 2021

      Two years in, and it's still the magic box for guitar!

      By way of full disclosure, I originally intended to order the Ox just to see what all the talk was about, play with it, and send it back. No way was I keeping a $1300 glorified direct box. It arrived in impressive packaging, very well protected for the trip. Call me shallow if you'd like, but packaging is the first clue to quality. You can tell if THEY think something is important in the box by what sort of box they put it in. Good start.

      I connected it to a few amps that I have never been able to run in their sweet spot live: a Carol Ann Tucana 3 and a PRS HX/DA, each directly into a 2x12 cabinet. Turning the attenuation down and the amp up, I was impressed to note that the sound wasn't compressed and lifeless, as many attenuators tend to do when pushed hard. I wish there were twice as many attenuation points, but what is there is serviceable in the real world. It has since been tested on a variety of other amps: a black face Deluxe Reverb, a vintage AC30TB, and on every amp, the result is the same... set it where it sounds good, control it with the OX, done. Test #1: Success!

      I downloaded the app to my iMac/DAW, followed the quick start connection guide and I was up and running in short order. As an aside, I totally do not get the comments on connection difficulty... following the instructions, it was a snap. The app is good, and has a lot of control. Getting around and assigning rigs is a bit tedious, but that's likely more my unfamiliarity than the app... most of the time I just use the box. Graphics are useful, and needless to say for UA, the effects are gorgeous and incredibly well implemented. The ability to add room mics really opens the sound and produces that "good studio" vibe into your sound. Test #2: Success!

      Then I put the two together, and was shocked at how good it can sound mixed. With a direct tone coming from the cab and an effected tone coming from the monitors, the sound is immersive. It gives you that great live guitar tone from the comfort of your favorite studio chair. This was not something I had really purchased the Ox to do, but it immediately became my favorite sound combination. (Unanticipated) Test #3: Smashing Success!

      So, I guess you could say the test drive very positive 3 for 3 sweep, and I would be happy to have found out what I wanted before sending it back. Well, that was two years ago, and the OX is still with me in regular use! Far from the fancy direct box I thought it was, the Ox Amp Top Box is an instrument unto itself, and you just need to open your mind to what it can be used for to see many possibilities beyond the obvious. I could take away stars for things I would like to see there, but this review is about what IS there, and that justifies the 5 Star rating. It is the best I have found for a guitar amp interface/attenuator/effector/expander/etc. It has become as much a part of the setup as anything else, and if you look around on YouTube, you'll find I'm not the only one who always has the orange Ox power light glowing in the background.

      I paid the money and didn't return it... there's no better score I can give it than that.

      t. edwards

      December 8, 2020

      Awesome for recording

      I had to wait until the firmware supported Windows, but have never had connection issues. So much different (better) than other load boxes I've used, and IR's are outstanding. Add in the "mic locker" , ability to add in room mics and effects, EQ and compression, all in one ap, and it's a game-changer. I have the space and the mics to mic-up cabs, but haven't done that since I got this box.

      H. Schmidt

      December 2, 2020

      Tolle Hardware, sehr schlechte software unter Windows

      Ein sehr schönes Teil, welches meinen Bogner Atma Amp im Wohnzimmer nutzbar macht. Leider ist es mir bis heute nicht gelungen, die App unter Windows zum laufen zu bringen. Für Windows-Nutzer, vermutlich 70 % aller Computer-Nutzer, ist die Ox-Box nur teilweise nutzbar und nicht empfehlenswert. Warum werden Windows-Nutzer so schlecht von Ihrem Unternehmen behandelt?

      M. Harvey

      September 18, 2020

      The Ox amp top box rocks

      Wow! I can't believe what a difference this has made for my recorded guitar tones. Being able to have my tube amp in its sweet spot playing through whatever cabinet and mic combo I'm looking for at the moment, and to have it feel and sound so awesome like I recorded it in a great space is phenomenal! This is going to bring my productions to pro levels. I'm recording through the spdif connection into my x8 Apollo interface and I couldn't be happier. If I just want to play without disturbing the household it's nice to be able to play through the speaker or headphones at reasonable volume and still feel that sweet tone, minus the cab and mic/room emulations though. As for the wifi connection issues I've seen others have posted, I haven't had any. I love everything this box does and wish I had known about it long ago. In my opinion it is much better than any of the amp plugins I've been using trying to achieve big realistic guitar tones. Thank you UAD! Like the Ox, you guys rock! And I didn't even mention the top notch onboard signal processing.

      J. Romanchik

      May 6, 2020

      Make it hardwire-able!

      Was REALLY looking forward to using this. But have been stuck using only the 6 presets on the front. Will not connect to WiFi. There is ZERO customer service! Dont want to return this but if i cant access the app there is no way it is worth $1300. ABSOLUTELY RIDICULOUS

      m. nelson

      February 17, 2020

      Updated Review: UA finally got it right

      about a year or so, I left a review of the OX, and I definitely shared my pros and cons. However, After a recent firmware update that brought more cabinets, and an overall better sound, I can say that this is the best of its kind.

      About 2 years ago, My band "Ornimental" started to record our second record and one of our microphones crapped out right in the middle of guitar tracking. When we heard that UA was making the OX, We got in line to pay for it pretty much immediately. After recording with the OX out of the box, It took us a while to get something we liked, and we weren't 100% on the sound. We ended up with the 4x12 greenback "punch" for guitars, but it wasn't up to our standard.

      I mentioned before that the OX was amazing for the old school guys that want that retro sound, but it's not too tone friendly with people desiring more modern sounds. Well, After their 2nd firmware release, I can say that everything sound incredible! Just have the V30 cabs in the library changed everything for us. Even though we can't go back to doing the guitars for the record, we are ready to tackle the next one with better tones!

      The OX is the best piece of gear for guitar recording!

      D. Williams

      February 16, 2020

      Innovative & Dynamic

      Unparalleled build quality, a plethora of more-than-realistic cab and mic options, results in lush tube amp tones to die for. Great product. My only complaint is the limited either/or wifi or internet connection. Hopefully, you all will develop a direct connection between computer and the ‘Ox’, this would be great. Nonetheless, I am blown away.

      J. Leyton

      January 25, 2020


      Love the OX and have had one since it came out. Rabear, you just get better and better. You are a real accomplished player now. Looking forward to hearing more from you.

      M. Tuttle

      December 21, 2019

      Quite Useful

      I bought one when they first came out and I've never had an issue. Updating via my Mac was no issue when following the instructions and having my iPad close by means it is very simple to change parameters at any moment.

      S. Lauzon

      November 27, 2019

      Lots of issues.

      I have the OX. I bought it about 7 months ago and it’s clumsy. Aside from the fact that you have to constantly switch WiFi to OX, then back to your router, even after you’ve set everything up! It’s ridiculous.

      There’s been a update, which I was excited about briefly. Here’s why:

      1. You need a usb flash drive to do this. It says you can do it over WiFi but not if you update the OX app first. My apps are setup for auto updates. So the firmware is incompatible and the app WILL NOT open because of this issue. I haven’t been able to open the app to change cabs or mics since nov 4th.

      2. Customer service is awful. I’ve had a ticket out for 2 days now and no reply... nothing.

      3. You may buy the wrong flash drive (as I did 2 times. Why two times? Well. It doesn’t say anywhere on the notes for the update which beans works. I’ve spent $30 and still can’t update firmware. The site says *try different one if not recognized. Yeah - cause I have lots of usb flash drives. They are almost obsolete....

      4. If you have the issues I’ve had, it’s a glorified paperweight.

      All of this is why I’m going to sell it at a 3-400$$ loss and go back to the easy to operate and use Mesa Cab Clone. I can’t honestly say I hear a 1000$$ difference anyway.

      Sam L

      G. Herrera

      November 23, 2019

      Faithful to this Unit

      Having bought this when it first came out, I was really Loving what it did for my recordings, and now with the Update, OMG so Complete! I can get any tone I need Period! The ease of use just makes it fun and Inspiring, this is worth every penny and will never get rid of this Unit. Thanks UA

      w. visbeen

      November 17, 2019

      No sleep but more than alive.

      Bought the ox mainly for attenuator function. Speaker connector combo too short. While waiting for cable dived into the cab emulations and haven't slept since. Can't remember having had so much fun with my amp. Thank you so much!