I am offering a Universal Audio OX Amp Top Box from 2020, a premium loadbox for guitar amplifiers with 150 watts of power handling and Dynamic Speaker Modeling featuring 17 different cabinet models and six high-end microphone models, Dynamic Room Modeling with six high-end room microphone models, Master Effects with 4-band equalizer, 1176 SE compressor, stereo modulated delay and stereo plate reverb, memory slots for 6 rigs consisting of speaker cabinets, close-field and room microphones as well as up to four studio effects, room control for adjusting the room sound within a rig, Speaker switch for adjusting the volume of guitar cabinets, separate volume controls for Line Out and headphone jack, 4 ohms, 8 ohms, or 16 ohms impedance, S/PDIF outputs, Wi-Fi connectivity for connecting to the OX Mobile App or Desktop App in a compact head unit format with power supply in mint condition, including original packaging.

The Universal Audio OX Amp Top Box is one of the highest-quality solutions for running classic tube amplifiers within their optimal operating range, even at volumes suitable for the living room, studio, or headphones. As a reactive load box and attenuator, the OX absorbs the power from the connected amplifier, allowing you to drive the power amp hard while reducing the actual volume of the connected guitar cabinet via the speaker switch. With a power handling capacity of up to 150 watts and selectable impedances of 4, 8, and 16 ohms, it can be paired with a wide variety of high-quality guitar amplifiers.

A particular strength is its extensive Dynamic Speaker Modeling. Seventeen different cabinet models can be combined with six high-quality virtual near-field microphones and fine-tuned in detail. The additional Dynamic Room Modeling, featuring six room microphone models, replicates the spatial characteristics of a professional microphone setup. This produces guitar sounds ready for direct recording without the need to mic a real speaker cabinet.

High-quality effects, inspired by Universal Audio’s studio experience, are available for further sound processing. These include a 4-band EQ, 1176 SE compressor, stereo modulated delay, and stereo plate reverb. Up to six complete rigs can be saved for direct access. Cabinets, microphones, rooms, and effects can be conveniently edited and combined via Wi-Fi and the OX app.

A sound sample of the model can be found above at the end of the photo gallery.

Thanks to separate outputs, the OX is equally suited for recording, live performance, and silent practice. In addition to the adjustable stereo line out, a headphone output as well as coaxial and optical S/PDIF digital outputs are available. At the same time, a real guitar cabinet can be connected and operated at various volume levels.

Technical Specifications:

• Year of manufacture: 2020
• Dynamic Speaker Modeling for detailed simulation of all components, featuring 17 different guitar cabinets and six high-end microphones
• Dynamic Room Modeling for simulating room acoustics, featuring six high-end room microphones
• Master Effects for fine-tuning the overall sound, including a 4-band equalizer, 1176 SE compressor, stereo modulated delay, and stereo plate reverb
• Memory slots for 6 rigs consisting of a speaker cabinet, close-field and room microphones, and up to four studio effects
• Room control for direct adjustment of the room sound within a rig
• Speaker switch for adjusting the volume when using a guitar cabinet
• Separate volume controls for Line Out and headphone jack
• Up to 150 watts power handling
• 4 ohms, 8 ohms, or 16 ohms impedance
• Headphone jack (6.3 mm jack)
• Stereo Line Out (2x 6.3 mm jack)
• S/PDIF outputs (Coaxial and TOSLINK)
• Wi-Fi connectivity for pairing with the OX Mobile app (iOS) or desktop app (available for macOS or Windows 10 64-bit)
• Includes Universal Audio power supply and original packaging

This Amp Top Box is in mint condition and works perfectly. It also shows no visible wear (see photos).

The amp has been thoroughly tested, and I (a long-time guitar teacher) can ship it via DHL with insurance upon request for €29.99 within Germany or for €49.99 within the EU. Worldwide shipping is available—custom shipping costs upon request.

All photos shown are of the actual Amp Top Box being sold.