Great performance at a great price — these are the benchmarks of a USX-4065 amplifier. Its four-channel design lets you send loads of power to all the speakers in your setup.

Front and rear crossovers (12 dB/octave high-pass and sharp 24 dB/octave low-pass) give you precise signal separation for ideal soundstaging, along with firm, tight bass. And preamp outputs with built-in crossovers simplify connections when you add more amps to your system.

Details:

  • 2-, 3-, or 4-channel output
  • Tri-way capable (Tri-Way crossover required)
  • 80 watts x 4 at 2 ohms
  • 160 watts x 2 in bridged mode
  • requires 8-gauge power and ground leads — wiring and hardware not included with amplifier
  • variable high-pass crossovers (12-200 Hz, 12 dB/octave), front and rear channels
  • variable low-pass crossovers (40-200 Hz low-pass, 24 dB/ octave), front and rear channels
  • preamp outputs with crossover
  • anti-thump circuit
  • thermal, short-circuit, and power/ground reversal protection
  • blue power light strip
  • 3-year warranty

My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

Hands-on research

What's in the box?

Download owner's manual

  • Blue amplifier with chrome trim and two 20-amp blade fuses in chassis
  • 1 Spare 20-amp blade fuse
  • 4 Plastic isolation mounting feet
  • 4 Self-tapping screws
  • 4 Flat washers
  • Manual
  • Warranty registration card with survey.

Product Research

Special Features
Controls
Inputs/Outputs
Additional Specs
Warranty Note

Special Features

True Line Output: The gold-plated RCA outputs on this amplifier are able to send flat (full-range), lowpass or highpass signals to a second amplifier. The position of the "selector" switch determines what is output through the RCA line outputs. The selector switch may be set to "low", "1+2" or "3+4". When set to "low", the lowpass frequency control sets the lowpass crossover frequency for the line outputs. Setting the switch to "1+2" allows you to set the RCA output highpass frequency with the channel 1+2 highpass selector, and selecting "3+4" allows you to set the RCA output highpass frequency with the channel 3+4 highpass selector. Either highpass selector may be set to "flat" for full-range output.

Power Supply and Output Devices: High current MOSFET devices are used in the power supply and output stages of this amplifier.

Anti-thump Circuitry: There is a time delay turn-on with opto-coupled muting circuits for quiet, thump-free operation.

High Speed, Audio-grade Components: High speed, audio-grade components are used in all low level stages to help ensure signal integrity.

Protection Circuitry: Reverse polarity, thermal and short circuit protection circuits are used to help protect the amplifier from damage and ensure reliable operation.

LED Condition Indicators: A green power LED and a red protection LED are use to report the amp's operating status.

Blue Light Strip: There is a blue light strip on the top of the amplifier. The light strip illuminates when the unit is on.

Controls

Lowpass Frequency Control:  This controls the lowpass frequency for all of the channels set for lowpass operation using the mode buttons. It is variable from 40-200Hz with a 24 dB/octave slope.

Mode Buttons: There is one mode button for channels 1 + 2, and there is a separate mode button for channels 3 + 4. Each button may be set for lowpass or flat/highpass operation. When a full-range signal is desired for a pair of channels, the mode button for those channels should be set to the highpass/flat position, and the highpass frequency control should be set to "flat". When a mode button is in the highpass/flat position and the highpass frequency control is in the "flat" position, all frequencies above 12Hz are passed through to the speaker outputs.

Highpass Frequency Controls:  There are two highpass frequency controls; one control is for channels 1 + 2, and the other control is for channels 3 + 4. The highpass frequency controls are continuously variable from flat (full-range) to 200Hz; the highpass crossovers have a 12dB/octave slope.

Level (gain) Controls: There are separate level controls for channels 1 + 2 and channels 3 + 4; the control settings are continuously variable from 110mV to 8.8V.

Selector Switch: The position of this switch determines the type of signals sent through the RCA line outputs.  It may be set to "low", "1+2" or "3+4". When set to "low", the lowpass frequency control sets the lowpass crossover frequency for the line outputs. Setting the switch to "1+2" allows you to set the line output highpass frequency with the channel 1+2 highpass frequency control. Selecting "3+4" allows you to set the line output highpass frequency with the channel 3+4 highpass frequency control. Either highpass selector may be set to "flat" for full-range output.

Inputs/Outputs

Inputs/Outputs:

  • +12V, Remote Turn- on and Ground Connections: gold-plated screw terminals; each terminal is 0.335" wide
  • Speakers Outputs: gold-plated screw terminals (R- and L+ connections are used for bridged mode); each terminal is 0.335" wide
  • Line In Connections: two stereo sets of gold-plated RCA jacks
  • Line out Connections: two gold-plated RCA jacks

Additional Specs

Best Frequency Response: 10Hz to 30kHz, -0.5dB.

Fuse Rating and Type: two 20 amp blade fuses

Channel Separation: 80 dB

Warranty Note

Warranty: Amplifiers made before January 2001 carry a 1 year warranty. Units made during, and after, January 2001 carry a 3 year parts and labor warranty. All the units currently being sold by Crutchfield were manufactured after January 2001, so they are covered by the 3 year parts and labor warranty. The production date of each amplifier can be determined using the serial number; the first digit in the serial number indicates the year in which the amplifier was made. If the first digit in the serial number is "1", or higher, the amplifier carries a 3 year warranty; if the first digit in the serial number is a "0", the amplifier carries a 1 year warranty.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team — they open the box, verify contents, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

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Get everything you’ll need to enjoy your new US acoustics USX-4065

Patch cables take the music from your stereo to the amplifier. Most amp wiring kits don't include them.
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