Universal Audio OX Amp-Top Box

Plug into this reactive load box to push your tube amp into sweet distortion at any volume -- and shape your tone with Universal Audio's speaker cab models.

Get the ultimate tone from your tube amp -- anywhere, at any volume. The Universal Audio OX Amp Top Box is a premium reactive load box, allowing guitarists to play and record their tube amp in its ideal sweet spots -- from the edge-of-breakup to fully cranked -- at any volume level, and with instant album-quality mic, room, and speaker cabinet emulations at the turn of a knob.

Featuring Universal Audio's breakthrough Dynamic Speaker Modeling, OX emulates speaker breakup and cone cry like no other box on the market. It's the world's finest boutique speaker attenuator and guitar amp recording solution -- overbuilt for years of home and studio use.

Join us as we take a closer look at the OX in our exclusive video:

Now You Can:
- Get the ultimate tone out of your tube amp -- anywhere, and at any volume
- Pair your amp to the world's best reactive load, with boutique UA analog quality -- built for years of home and studio use
- Instantly audition dozens of album-quality mic and guitar cabinet setups with front panel "Rig" control
- Get authentic "edge of destruction" tones complete with speaker breakup and cone cry, thanks to UA Dynamic Speaker Modeling


- Premium, no-compromise analog reactive load box for tube guitar amps
- Five finely-tuned guitar amp attenuation levels -- from off, to whisper quiet, to full band volume
- Front-panel "Rig" control for instant, album-quality mic and speaker cabinet emulations
- UA Dynamic Speaker Modeling emulates speaker read more 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 outputs for stereo recording
- Pair with OX mobile or desktop app over Wi-Fi for editing and saving presets
WARNING: Cancer and Reproductive Harm - www.p65Warnings.ca.gov.
read less

Dimensions and Weight in Packaging
Base Item
Shipping Weight: 20 lbs
Shipping Dimensions: 22 x 13 x 12 in
Manufacturer Part Number (MPN): OX

For support or warranty questions, please contact the manufacturer:
Phone: 831-440-1176
Web: https://help.uaudio.com/

Reviewers gave this product an overall rating of 5 out of 5 stars. (4 ratings)
Submitted January 15, 2023 by a customer from yahoo.com

"OX has been good to me."

Overall: 5 out of 5 stars
(see rating details)
Verified Customer zZounds has verified that this reviewer made a purchase from us.
UA is a company that charges a premium, yes. But I feel I’ve gotten excellent value unavailable anywhere with every purchase including The OX. This attenuator has worked great, I haven’t experienced the microphone distortion. I’m running modern guitars through modern amps with fresh tubes. With included presets sound comes out of the optical and into my x8p as a beautiful soundscape. If you understand a little more and go beyond presets, there is quite a bit to adjust to your liking. I’ve laid down quite a few tracks that got a tone and effect with a desired separation at a minimum of effort. If you use the cone cry feature with some understanding as well. You can replicate and amp that barks and squeals, as intended. Not microphonic. Now I’ll add that I run a clean amp platform and pedals for beyond that. I reuse power section. El34, EL84, 6L6 AND then switch out the pre’s. The victory v4 series all four (kraken, sheriff, countess, copper) so 5150, modern Marshall, plexi, and ac30 essentially. Again great results on all of it. Ran for several years now. Very satisfied with the product. As with everything, there can be an amount of user error. I haven’t met anyone with a bad ox experience. Different gear has different quarks. Learn your gear, and you can love it for what it is then.
4 of 4 people (100%) people found this review helpful. Did you?
Thanks for your opinion!


  • 12 x  
  • 8 x  
FREE -Day Shipping!
Get it  for
Get it by if you order within
Shipping to