Published On July 15, 2018 | Reviews

Dummy load boxes are just that… dumb. UA’s Ox is much more.

Review: Preshan John

The struggle is real. You’re trying to lay down electric guitar tracks through a vintage tube amp and quad — in your living room. The guitarist insists the ‘true tone’ of the amp exists beyond the halfway Volume knob mark, but it feels like the beastly 100W head explodes with the slightest twist above two. Mattresses go up and curtains are draped to counteract the tsunami of SPL but with little effect on your neighbour’s nerves. You resort to an amp simulator plug-in. 

The UA Ox is designed to solve this age-old problem for guitarists. The Ox can be used in two ways. First, you can hook up a cabinet direct so it acts as an in-between load box to allow your amp to enter its favourable range while maintaining full control over the level sent to the cabinet, without sacrificing tone. Second, you can use the several cabinet emulations which already exist inside Ox to complete your tone. This means you get genuine tube amp tone and feel but with the ability to tap that tone as a line signal into whatever you want — be it a DAW in the studio or a mixing console on the stage. 


Physical connections include Line Out and Headphone outputs, both of which are post-cabinet emulation, then there’s a Speaker output without cab emulation to go directly to a physical guitar cabinet. In addition, there’s an S/PDIF output via RCA or Toslink and a footswitch port.

A number of chunky switched knobs adorn the front panel. Out of the box, the six positions of the Rig knob provide quick access to different preset cabinet and mic configurations. The Speaker Volume knob sets the level going to a cabinet and the Room knob controls the room ambience volume. 

With a Marshall JCM 2000 Dual Super Lead tube head connected to the Ox via the 16Ω input, I plugged in my Strat and had a strum with the Rig set to Position 1. Listening through a JBL eight-inch studio monitor connected to the Ox’s Line Output, it felt like playing through an amplifier — because I was. The best part is I could crank the Marshall’s output to a glorious tube-y crunch and dial down the Ox output to enjoy every drip of tone without blowing the windows out. 

Now, not all load boxes are created equal, which is why some (Ox included) can cost the equivalent of a boutique amplifier. Ox has a fully analogue reactive load onboard, which means it has a continuously variable impedance and response, to counter the varying attenuation. In short, it sounds good no matter what head you plug in, or what level you run it at.


To get the most out of Ox’s inherent abilities you’ll need to make it talk to its own app via a computer or iOS device. After downloading and launching the Mac app, follow the on-screen prompts to first connect to Ox’s built-in Wi-Fi, then connect it to your usual Wi-Fi. Once you are told the software has been registered, the Ox app GUI appears. I love that the interaction between Ox and device is completely wireless, especially when you have the unit sitting with your guitar amps at the other end of your studio. 

The interface is basic and intuitive. First, there’s the rather extensive list of cabinets ranging from a 1×10 to several 4×12 varieties. 50W/100W output level options are provided and the Speaker Breakup knob lets you “control the harmonics and sonic complexity that occurs only at certain frequencies and volume levels on various speakers”. No complaints here whatsoever — playing through the cab emulations is a thoroughly lifelike experience and UAD’s modelling and DSP prowess shines in each model. 

Level/Mute/Solo controls for Mic 1, Mic 2 and the Room Mic let you find the perfect balance capturing the cabinet’s tone. Mic emulations include an SM57, MD421, R121, 160, U67, C414 and Direct. A four-band graphic EQ with HPF and LPF is provided for each mic, or you can choose a parametric EQ if you prefer. I was impressed with the natural character of the Room Mic channel and the Damp switch (which puts a rug under the amp).

The best part is I could crank the Marshall’s output to a glorious tube-y crunch and dial down the Ox output to enjoy every drip of tone without blowing the windows out.


On the Master channel is a tasteful chain of an EQ, 1176 SE Compressor, Delay and Plate Reverb inserts. These effects are what I think makes Ox more than just a load box. It’s a self-sufficient, stage-ready guitar rig. Many guitarists will find there’s more than enough configurability within Ox to get you through a show without needing tons of pedals or extra gear.

Of course, the app allows you to create and save your own presets. Click Assign at the top of the app to designate any of these presets to the six positions of the Rig knob on the unit for easy access to your favourites.

As a recording solution Ox offers loads of tonal options and outputs to work in any studio setting. Its app integration and preset-building ability makes it comfortably handle the demands of guitarists playing live. Whether your home is the studio, the stage, or both, Ox is a well implemented fix for amp lovers who never get to turn their amps up.

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