Why Choose Crutchfield?
Great gear and expert advice
Our experts help you pick the ideal gear for your needs.Meet our advisors
Free tech support for the life of your gear.Read about our one-on-one expert help
You may return items that are complete and like new for any reason within 60 days.See the details of our return policy
Earn one point for every dollar you spend and use those points to save on future purchases.Get full details on Crutchfield Rewards
Deep discounts on car installation gear
We offer vehicle-specific installation instructions, dash kits, wiring harnesses, and speaker accessories at deeply discounted prices with car stereo and speaker purchases. Available for most vehicles.Learn more
Trusted since 1974
Our customers have trusted us with their business, and they’ve helped us win awards for our service.Check out our most recent awards
The manufacturer’s warranty always applies.See more details
US Acoustics USX-4085
85W x 4 Car Amp
Item # 235USX4085 | MFR # USX-4085
This item is no longer available.
Our take on the US Acoustics USX-4085
Here's a reasonably-priced solution to the challenge of powering multiple sets of speakers with one amp. The USX4085 multi-channel amp from US acoustics is a rugged, terrific-sounding powerhouse that can drive a variety of speaker combinations. And built-in selectable high-/low-pass variable crossovers on its preamp outputs means you can add another amp, but you won't need to buy a separate component crossover.Details:
- 2-, 3-, 4-channel or Tri-Way output
- 85 watts RMS x 4 at 4 ohms
- 240 watts RMS x 2 in bridged mode
- MOSFET output devices
- 2-ohm stable in stereo
- anti-thump circuit for quiet turn-on
- thermal, short-circuit, and power/ground reversal protection
- gold-plated differential preamp inputs to reject noise
- MOSFET power supply
- 12-200 Hz high-pass crossover (front and rear), 12 dB per octave
- 40-200 Hz low-pass crossover (front and rear), 24 dB per octave
- preamp outputs with selectable low-/high-pass crossover
- THD at rated power 0.01 percent
- 101 dB signal-to-noise ratio
- 35 amp fuse
- 17"W x 2-1/2"H x 9-5/8"D
- 1-year warranty
What's in the Box:
- Blue amplifier with chrome trim and US Acoustics logo w/ a 35-amp blade fuse in chassis; 4 isolation plastic mounting feet; Manual; Warranty registration card with survey
- NOTE: 4 self tapping screws (not included) are required for mounting
Features and Specs
|RMS Power Output (Watts x Channels)||
85 x 4 |
|Peak Power Output (Watts x Channels)||N/A|
|Power at 2 Ohms (Watts x Channels)||120 x 4|
|Bridged Power (Watts x Channels)||240 x 2|
|Minimum Impedance Bridged||4|
|Minimum Impedance Unbridged||2|
|Best Frequency Response||10-30k Hz|
|THD at Rated RMS Power||0.01%|
|Signal to Noise Ratio||101 dB|
|Low-Pass Crossover Frequency||40-200 Hz|
|Low-Pass Slope (dB/octave)||24 dB|
|High-Pass Crossover Frequency||12-200 Hz|
|High-Pass Slope (dB/octave)||12 dB|
|Bass Boost Frequency||---|
|Speaker Level Inputs||No|
|Preamp Outputs||1 pair Gold RCA|
|Parts Warranty||1 YEAR|
|Labor Warranty||1 YEAR|
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 slope.
Mode buttons: The mode for channels 1 & 2 and channels 3 & 4 an be set to lowpass or flat/highpass. When a full range signal is desired this button is set to highpass/flat and the highpass frequency is set to the "flat" setting which allows all frequencies above 15Hz to pass through.
Highpass frequency: This controls the highpass frequency for channels 1 & 2 and channesls 3 & 4. It is variable from flat to 200 Hz with a 12dB slope.
Gain control: There is a variable gain control for channels 1 & 2 and channels 3 & 4 from 110mV to 8.8V.
Selector switch: This is used to determine what is output through the RCA preamp outputs. It may be set to "low", "1+2" or "3+4". When set to "low", the low pass crossover sets the low pass crossover frequency for the line outputs. Setting the switch to "1+2" allows you to set the RCA output high pass frequency with the channel 1+2 highpass selector (note that this can be set all the way down to flat if required). Selecting "3+4" allows you to set the RCA output high pass frequency with the channel 3+4 highpass selector (note that this can be set all the way down to flat).
Power: When the power is on a green power LED lights.
Protection: There is a red protection LED.
There is a gold plated terminal strip for +12V, remote and ground.
There is a gold plated terminal strip for left and right loudspeakers for channels 1/2 and 3/4.
RCA preamp outputs: There are gold plated stereo RCA outputs.
RCA preamp inputs: There are two pairs of gold plated stereo RCA inputs.
The amplifier uses high current MOSFET devices.
There is a time delay turn-on with muting circuits.
The protection covers reverse polarity, thermal and short circuit.
The amplifier uses high speed, audio-grade components in all low level stages
Power output is at 12.9V
RMS x 2 Ohms: 120 watts x 4
Channel separation: 81 dB
Best frequency response: 10Hz to 30kHz, -.5dB
Fuse: 35 amp blade
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 verify what’s in the box, 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.