OX Amp Top Box

OX Amp Top Box

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(82 reviews)
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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.

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.

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.

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

      OX App Requirements

      • OXAmp Top Box
      • Wi-Fi network with internet connection to register (once only)
      • (iPad) iOS 11
      • (Mac) macOS High Sierra
      • (Win) Windows 10 64-Bit Edition

      For complete compatibility information, visit help.uaudio.com

      Customer Reviews

      OX Amp Top Box

      Overall Rating

      (82 reviews)

      O. Harkoma

      October 14, 2019

      Great tool for tube amps

      I use this with my 87' Marshall 100W Silver Jubilee head, works and sounds great, only missing piece is really the V30 speaker model. Also tried it with small 20W Koch combo and it sounded completely crap with distortion, however pretty ok with clean channel. Seems like no one size fits all and perhaps you want to test with your tube amp before buying. I personally like the control over wifi, no issues using with iPad, Mac and now Windows also.

      C. Holmes

      October 5, 2019

      Connection Woes

      I find it insane that you can't connect the Ox to your computer via a USB or Firewire cord and have to rely on a wireless signal. The disconnections I kept encountering via the WiFi put me off on it entirely. I ended up returning it, which is a shame because I've been having a lot of problems with my Two Notes Torpedo Studio, which is the other loadbox I use, and was very hopeful that the Ox would be a worthwhile alternative. This is really a major design flaw that I'm stunned UAD hasn't done anything to address.

      D. Nelson

      August 15, 2019

      It's absolutely amazing...for a specific audience

      I've own this very well made, and fun to use load box. It's the guitar player's dream top box for studio, practicing, or even live shows if you know how to take care of it. I don't recommend taking it out on gigs because it is very fragile. I've owned this top box for over a year, and I can tell you what I think about it.

      So my band "Ornimental" is a Hard Rock/Metal band that used this for our record we recorded and we got pretty great results...for anything besides heavier music. We used different cabs, and used a lot of the UA plug ins this came with. I thought it was really cool that they did that. Unfortunately, When it came to heavier tones, which my band uses most of the time, it just doesn't cut it. It's obvious that this was marketed to players that love tones that are more on the vintage side. There's really no way to get contemporary heavy tones with this box, and it's a little disappointing. I also heard the UA has no plans on adding any kind of V30, or other speakers that are good for the style, so that's a let down too. It's great for Rock, Country, Blues, Jazz, Funk, and any other style you can think of that doesn't require a lot of dirt. We got great results with other styles, but Harder styles just won't cut it here.

      I'm sure that if I ever record with a different band thats a totally different style, this will do great, but the OX is made for vintage lovers and as much as I love vintage gear, I do need tones that are more modern and I feel like this would of blown away any other competitor.

      I honestly believe that a V30 cab option would of been the answer to our issues. I'm not sure why the OX didn't come with it especially since it's arguably the most popular 12 inch guitar speaker ever aside from the Greenback. I've also heard that other people have asked if there will ever be an update with a V30 cab. That would be amazing!

      It's an awesome piece of gear, but it's definitely not perfect. After some updates on a V30 option, and possibly more microphone options, I think it will be miles ahead of where it is now.

      - Danny

      S. Lauzon

      June 16, 2019

      Top Notch Top-Box

      First off, this is a 5 Star item. I gave it four because if 2 simple things.
      1.) you cannot be connected to the internet and the top box at the same time. The top box sends a WiFi-type signal you must connect to to make Cab/Mic adjustments. That’s kind of ridiculous. Almost everyone uses the internet on their pad while recording. It needs to be fixed.

      2.) the options are limited where as TwoNote gives you 100’s of options.

      So now with the cons out of the way. The sound is simply unmatched. The quality and ability this box performs with is, simply, amazing!

      The little details UA took to make this thing look and feel amazing is brilliant. The ease of use is awesome (a little clunky) but when you need to make adjustments the window seams to close and you have to start over when switching between DAW and TopBox. I have found the missing piece and am thrilled to have it.

      Please update cabs. Also plugs would be huge. It comes with a great limited plug but that’s really all it comes with - aside from a reverb and delay. It’s awesome still but could use some updates.

      Sam L

      r. seo

      June 14, 2019

      upgrade please

      this is very usefull, I'm playing back on my VOX HWX1 and it is so pleasant.
      BUT, it desyncrhonises in logic pro x while recording resulting in a crazy depitch digital noise... like a drunk DJ.
      Otherwise, this is going to be really good when upgraded.

      M. Music

      June 10, 2019

      Mediocre reactive load and no updates so far?

      I've got the OX for over 14 months now and found out the impedance curve of the OX reactive load is based on a 'bathtub', not a real speaker cab as they claim, its similar to the Two Notes Captor load. It lacks the low resonance peak, so their is no low frequency amp response. For a 1300 euro load box you would expect more! As an alternative i use the OX now with the Suhr Reactive Load and OX load in parallel which makes my amp respond much better and makes the cab modeling sound better, especially with the 4x12 and 4x10 cabs.

      No updates, no platform, no way to backup your presets. I gave them 3 starts when i bought it but now i give them 2 stars as its way overpriced for what you get in this box. The cab modeling software sounds great but a simple native plugin would do it for me as the load is mediocre and the IO limited.

      m. pilsworth

      May 20, 2019

      Just what I have been looking for...would like ditch the ipad though

      I use mine mostly for home recording and love it - the build quality inspires confidence and being able to overdrive at midnight without causing a riot with the neighbours is a dream come true. To me the sound quality is amazing and find the presets a great starting point for experimentation. Don't have too much of an issue with the lack of XLR as my Apollo Twin only has trs line inputs anyway. I have just started using a Windows based system and would very much like to ditch my ipad and hook up to my PC with USB though.

      D. Panczykowski

      May 9, 2019

      Whoever invented this should receive a Nobel prize

      Absolutely incredible and freakishly accurate. I had previously been utilizing Aaracom attenuators with vintage Marshall and Fenders, as well as Metropoulos and Alessandro heads . However, had to relocate to very small apartment for work and even 'bedroom level' was not going to cut-it. Refusing to give up the tone I strived my whole life to find, I bought the Ox and prayed it would be 'manageable' enough for 1-year.
      I've now put this thing through its paces for 1-year and I am still blown away every day by the tone. I am currently running those same amps into the Ox, then into a small mixer (via stereo XLR), then into Bose headphones. I literally can't believe the quality of what I'm hearing. The sound is natural, alive, sensitive, dynamic, and without any loss of the amp's voice. This is a truly monumental accomplishment on par with the moon landing or at least Beauchamp/Rickenbacker mounting the first pick-ups on a guitar.

      J. Henderson

      May 9, 2019

      Was essential...getting over it

      It's cool, it's handy, it does the job. But...no updates in forever. I'm getting bored with it. I miss speakers that move air into well-placed mics. I HATE the wifi/ipad aspect. Just let me connect via, you know, the USB port that does nothing. There's a lot of untapped potential. This could be an industry standard, but it seems UA has lost interest. Sad to say I am as well. Come on, UA...breathe some life into this thing.

      A. Cerceau

      May 5, 2019

      Oui mais ...

      J'ai l'impression que UA a juste laché un produit inachevé ..
      Pas mal de point faible par rapport à la concurrence qui a effectué beaucoup de mises à jours
      Pour moi voici les principaux point faibles :
      - Clipping numérique avec certain amplis pourvu de beaucoup de headroom ( je pense aux amplis comme Two-Rock et cie )
      - Aucun Cab fonctionnant bien pour du High Gain
      - Échantillonnage limité à 48K ( c'est une blague ??? )
      - Auncune mise à jours ( Non Universal Audio votre application est loin d'être parfaite )

      Une Update est vraiment nécessaire ( je ne parle pas qu'en mon nom, dans mon entourage nous sommes beaucoup à regretter tous ses désagréments, j'ai même des amis qui repartent sur du Two-Note ou encore d'autre qui vont aller sur le Boss Waza Tube Amp Expander..

      Universal Audio S'il vous plait, au lieu de dire que vous n'avez pas abandonné ce produit, faites quelque chose...

      J. Woodham

      April 28, 2019

      Ox Amp Top Box

      The ox is built like a tank with top quality components and sounds great .
      iPad app works fine’ finding ox works okay .
      ....but would be great to be able to download UAD plugins so I had some choice to what I can use on the ox.
      Really hope UA has updates for the future as now rival brand has brought out similar product with more functionality.
      Might sound greedy but more cabs ‘effects’ and a choice to purchase plugins would be great.
      In all a good start but with room for improvement if possible make usb function with a computer.
      Sound quality five stars but given four because unsure about future updates/functionality .

      R. Mohammed

      April 27, 2019

      Absolutely WOW!

      Using the OX in conjunction with 60's Fender and 70's Marshall and Hiwatt heads. The tone is amazing right out of the chute. The speaker and mic modeling is very flexible so there is always a tone to be found. Works well with pedals and retains harmonics, which is the difference between a lifeless guitar sim and the real deal. This box costs more than others, but so do Aston Martins. Don't be a square, get an OX!

      M. Farnsworth

      April 25, 2019

      Where are the updates?

      The unit sounds great, that's for sure (unless you play high gain and need chug). But it's been over half a year since the last update, and there have been no updates that unlock the footswitch or USB functionality. No updates that add V30 or other essential speaker types. Seems to be abandoned by UA while they focus on their digital products.

      K. Jacobsen

      April 20, 2019

      Love it, but.......

      Love this thing, it sounds fantastic, it has great intentions and it’s versatile. But there are a few things that I have issues with. It should have XLR connectivity to be truly a pro product. Physically it is a problem for me to have a good placement for it in my studio, it should be rack mounted. It bumps of the wifi network regularly and need resetting. I wish it had more than one amp input. It should have higher sample rate on the digital output. I wish the on/off switch was on the front. That said, now I can’t work without it. It’s here to stay. Rock on!

      J. Brazinski

      April 8, 2019


      This is now one of my favorite pieces of guitar gear. I have it in a rack/amp head case for gigging, going straight out of the L&R outputs to FOH, and it works so incredibly well with my Fender Prosonic head.

      The cab simulation adds a bit more amp color than I would like (i.e. the vox speaker adds more of a vox-y sound than just a straight cellestion blue would, but it does transform any amp into something completely useable. A remarkable piece of equipment for the studio or on tour.

      Crystal clear sound that absolutely rivals any Kemer or Helix amp sound.

      D. Brehm

      April 6, 2019

      XLR-Output missing

      My sound engineers always wonder why there are only symmetric instrument outputs and no XLR. By using a DI-Box sound is not getting better. To avoid that a cable XLR female to instrument symmetric is needed. For such a price an XLR plug should be possible.

      M. Stiso

      March 21, 2019

      Wi-fi control is stupid

      not sure why UA thought controlling this with ONLY an iPad or computer was a good idea. Do they actually try and use this stuff? If I run a session with Pro tools using a dock the iPad needs to be on the same network as the computer running pro tools. Can't use the OX network. I have a second iPad mini but UA doesn't support that. There are however 3 USB outputs on the stupid thing but they are not functional at this time. I generally
      think highly of the UA stuff but this seems to be not well thought out.

      J. Vogt

      March 21, 2019

      The Amazing OX Amp Top Box

      Picked this amazing OX box up in January. I use every aspect of this product. It gives me amazing attenuation on all of my amps. I now have the ability to use headphones through all of my amps as well as having a separate volume for headphone output. The App and the software is extremely good and customizable. My only gripes are the need for guitar cabinets with V30 speakers. As well as sometimes having issues with the OX connecting to the app via my wifi connection. Yes, I'm using comcast Xfinity internet with a 2.4 speed connection.

      O. Schiavo

      March 8, 2019

      AMAZING only for iOS users?

      OX Amp Top Box is FANTASTIC! But software App only for Mac/iPad is punitive...

      t. klein

      February 22, 2019

      un autre monde

      je l'ai acheté pour l'utiliser comme atténuateur ( il y excelle ) et je m'en sers finalement comme simulateur de HP. je n'ai jamais entendu mes amplis avec tant de précision, je n'ai jamais eu tant de contrôle sur le volume. c'est juste fabuleux.