Important Notes - Reduce Equipment Wear - Universal Audio OX Operation Manual

Rated Speaker Power
DON'T connect OX's TO SPEAKER output to any speaker that is rated for a power level that is
significantly less than the connected amplifier's output power to avoid speaker damage.
Moisture and Liquids
DON'T expose OX to moisture or liquids. Make a habit of never putting beverages on your OX. If
liquid is spilled into the unit, immediately unplug the power cord from the AC socket.
Cooling Airflow
DON'T cover OX's air vents or otherwise restrict airflow around OX. The amp's output power is
converted to heat by OX's fanless attenuation circuit, and the air vents must be unrestricted to
dissipate this heat.
Solid State Amplifiers
Using OX with solid state amplifiers (amps without vacuum tubes) is not recommended and not
supported. OX is designed and optimized for use with tube amplifiers only.
Important Notes
Circuit Wear with Power Attenuation
Circuitry within an attenuated amp is subject to the same wear and tear that would occur if
its output power was not attenuated. If an amp is constantly run at higher power levels, the
lifespan of an amp's components is reduced accordingly.
Increased circuit wear applies especially to the amp's vacuum tubes, capacitors, and
transformers due to the increased heat and current generated at higher power levels.
Tip: A tube amp's sweet spot might not be at full output power — a "dimed" amp
doesn't always sound better. Less power and soak might deliver better tone AND better
tube life.
Impedance
Set OX's IMPEDANCE knob to match the impedance of the tube amp's speaker output.
Similarly, the total impedance of speaker(s) connected to OX's TO SPEAKER jack should match
OX's IMPEDANCE knob setting.
Many tube amps have multiple speaker output jacks with different impedance labels (4Ω, 8Ω,
etc.) for each output jack. If the amp's speaker output impedance cannot be determined, set
OX's IMPEDANCE knob to 8 ohms.
Note that when multiple speakers are combined (such as in a multi-speaker cabinet), the total
impedance depends on how the speakers are wired together. For example, two 8 ohm speakers
wired in series has a total combined impedance of 16 ohms, but if they are wired in parallel,
the total combined impedance is 4 ohms.
OX Amp Top Box
— Reduce Equipment Wear
8 Critical Operation Notes