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Universal Audio OX Amp Top Box


Analogue Loadbox

  • Analogue reactive loadbox for guitar tube amplifiers
  • Five tuned guitar amp attenuation levels
  • Rig control for pre-set microphone and speaker box emulations
  • UA Dynamic Speaker Modelling accurately models the behaviour of a speaker and membrane resonances
  • Integrated UA EQ compression, delay and reverb effects
  • Ohm operation selectable (4, 8, and 16 Ohm)
  • Max. power handling: 150 W
  • Connectors: Line output 6.3 mm jack balanced
  • S/PDIF output
  • Headphone output: 6.3 mm jack
  • Pairing via WiFi with OX mobile or desktop app to edit and save presets (for Windows 10 and macOS: Sierra or High Sierra)
  • Suitable cases: Article Nr. 469012 and 505416 (both not included)
Available since January 2018
Item number 418430
Sales Unit 1 piece(s)
Impedance 4, 8, 16
Noise Supression No
DI Interface Yes
Speaker Simulation Yes
Dummy Load (usable without cabinet) Yes
B-Stock from £1,111 available
All prices incl. VAT
In stock
In stock

This product is in stock and can be shipped immediately.

Standard Delivery Times
Delivery free of charge expected between Thursday, 18.07. and Friday, 19.07.

A solution for silent guitar recording

The OX Amp Top Box from Universal Audio is an analogue silent recording box that can be used to authentically capture the tone and dynamics of any tube amplifier in outstanding quality. This setup allows the player to set their amp to its sweet spot - however high that might mean cranking the volume - and to enhance the sound further by adding Universal Audio's high-quality microphone, room, and speaker simulations while recording. The dedicated and easy-to-use software app can also be used to programme and control the Universal Audio OX Amp Top Box via WiFi.

The ideal load box

The OX Amp Top Box is a high-quality reactive load box in an amp head-style format that gives guitarists the freedom to play and record whenever they want and at any desired volume. What is more, UA's groundbreaking "Dynamic Speaker Modeling" technology means that the amplifier actually perceives the OX Amp Top Box as a speaker, and its tone, dynamics, and feel are thus captured with the same authenticity as if it were being played through a real speaker cab. The speaker breakup control found in the app adjusts the harmonics and sonic complexity that occur at specific frequencies and volume levels, and the OX's front panel features dedicated volume controls for headphones, speakers, and the line output.

Universal Audio OX Amp Top Box Analogue Loadbox in action

For quiet players and recording specialists

All too often, getting the best tone out of a tube amplifier inevitably means having to crank the volume up to unbearable levels, and Universal Audio has designed the OX Amp Top Box to tackle this age-old problem and allow users to play, practise, and record with one hundred percent of their amp's tube tone at any time of the day or night.

Universal Audio OX Amp Top Box Analogue Loadbox with app

Tube amp tone on tap 24/7

Universal Audio's OX Amp Top Box gives players the freedom to fully enjoy the sound of their tube amplifier at any volume level - whether they are trying out new riff ideas at 3 o'clock in the morning or practising and recording - without disturbing anyone. As mentioned above, recording is also possible even without the use of a speaker cabinet, and users additionally have Universal Audio's authentic-sounding mic, room, and speaker simulations at their disposal, providing even greater sonic flexibility.

Universal Audio Logo on the OX Amp Top Box Analogue Loadbox

About Universal Audio

Few manufacturers can draw upon a wealth of audio engineering experience comparable to that of Universal Audio. The company’s founding father Bill Putnam, along with his friend Les Paul, have an admirable reputation as trend-setting music producers and developers of legendary analogue studio technology. Putnam recorded Chuck Berry, Muddy Waters, and Sarah Vaughan, and was Duke Ellington’s favourite sound engineer. He developed the famous 1176 Peak Limiter and distributed the Teletronix LA-2A level amplifier. This earned him a posthumous “Technical Grammy Award” in 2000. In 1999, Putnam’s sons, Bill Putnam Jr. and James Putnam, re-founded Universal Audio, transferring their father’s analogue vision and craftsmanship to the digital music world. Their product range includes audio interfaces, dedicated DSP farms, and a variety of plug-ins, as well as analogue hardware devices.

The separately available software for Mac and iPad provides maximum access to all of the OX Amp Top Box's presets, parameters, and effects and gives the user a clear and comprehensive overview of all the relevant information, allowing them to select the right speaker, microphone, and EQ settings easily and intuitively.

In the spotlight

135 Customer ratings

4.8 / 5

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98 Reviews

A must have for valve amp lovers
Allthatjazz 17.12.2019
The ox Box is sturdy and robust. The attenuator is easy to use but has a very slight volume drop even when not in use. Not to be compared with the Boss Enhanser because it does not use reamping. No IR simulations but a one of a kind modulation. My old 100 watt amp heads can be used at a non-deafening volume and recording becomes as easy as a walk in the park. To bad it had an external power adapter and software updates are rare.


Good, not great
SnapTheMag 15.01.2023
I'm currently using this for a Marshall 100W model 1959 Plexi and a 100W JCM800 2203X.

As a recording device:
The speaker and microphone simulation, as well as the built in effects are excellent. But the box is missing a balanced line out to round out the package.

As an attenuator/load box:
Works very well when playing with no speaker attached over headphones, provided you have some good headphones.

Unfortunately when using the speaker the sound is severely muffled with normal bass but greatly diminished mids/highs. And there are only 5 volume options due to a stepped knob controlling the speaker output.

Overall a quality piece of equipment, but lacking the last few features that would make it truly great.


Top notch product that allows you to get the most out of your gear
TheYearThree 22.03.2020
I live in an apartment and use the OX with headphones and it's an unbelievable tool for getting the most out of my tube amp at home. I also use it in recording setting without the speaker engaged to prevent microphone bleed and again it does not disappoint. Because of the OX I've gotten to become far more familiar with everything my amp, pedals, and guitars are capable of and I yet to experiment more with the different microphone and post effects available with the software. One drawback is that the cable that powers the OX is faulty and has the tendency to fall out because of a poor connection. Despite this, I would recommend this product to everyone. It's been a game-changer for me


Very Impressive
PeteW 16.05.2018
I've been using Suhr reactive loads and Spear IR's for a while now but easy portability of sounds between studios led me to look at the OX. the quality of the simulations is superb as you would expect. I was initially worried that I might not be able to get "my 1265 cab sound" as currently you cannot add custom IR's. However, I quickly found a '65 preset and nailed the tone/cab I'm used to hearing. Room eq, Mic's etc are all excellent and the quality of effects - especially the reverbs are superb and very usable. Very little tweaking needed.

My only disappointment is the inability to connect to the Ox via an iPhone app (although manual implies this is possible) - It can only be done via iPad app. I always carry a phone with me, but would rather not carry a pad around especially live. Also I don't run El Capitan and the current software cannot support this. El Capitan is not that old so I'm disappointed by that decision. Overall software is pretty good on the iPad - fairly easy to navigate and call up/store presets etc

Overall - Superb unit - pricey but worth the outlay.


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