Product Description
There is a before and after when it comes to Mercedes. The after, which the history of cars, made a U-turn to the right direction. The anchor of this drastic change emerged from the emergence of antique reproductions. Most of the smooth and elegance of the Mercedes vehicles came outfitted with some of the very first radio designs, that came with a single speaker fixed in the dash, and a less than optimum functional reception apparatus. And this has become one of the many things that true and loyal car collectors adore about the Mercedes. The challenge for the insatiable collector is to keep that stock setup with advanced-technology sound capabilities. Let’s face it, no matter how flawless your Mercedes looks on the outside, you must have the quality sounds to go with it. When you are cruising down the open interstate with the Mercedes top down listening to a static filled AM station through a single speaker, it just takes the ambiance away. No matter what, you just can't get great quality sound out of a noisy convertible with 1960’s technology. Yet, all is not lost. The brilliant minds of Custom Autosound are the architects of this innovative concept that managed to turn an ongoing issue into a viable solution. The USA-740 unites that classic look with today’s technology.
Custom Autosound USA-740 Classic Car Radio With Bluetooth USA-740 Radio with Bluetooth Features:
- AM/FM Radio Bluetooth, USB & Auxiliary Inputs
- Option to Add CD-1, Single CD Player
- Bluetooth is Built Into the Radio
- Fits in your Original Dash Opening Without Cutting
- 3.5mm Aux Input on Front of Radio
- RCA Aux Input On Back
- Change Display Lettering Color
- Digital Tuner
- RDS Song/Artist Information
- 5 Channel RCA Pre-Outs w/ Subwoofer Control
- Separate Bass & Treble Control
- 5 EQ Presets
- Fader and Balance Control
- 15 FM & 10 AM Pre Sets
- Seek/Scan Function
- Back by a 2 Year Warranty from the Manufacturer
You can be sure that they have done their homework, and you will discover that your modern sound is just an online order away. The original Mercedes utilizes a positive ground electrical framework; the vast majority of the original stereos available today only operate with a negative ground electrical framework. The installation of a customized USA-740 eliminates this along with all other obstacles instantly. The correct wiring system is already in place and Custom Autosound makes the conversion as simple as watering a plant with any and all potential issues already taken care of for you. After installing the 740 system, you can enjoy the pleasures of pure sounds coming from that original look. It is a custom car marriage made in restoration heaven.
Custom Autosound stands by their product by backing their USA-740 with a multi-year warranty. We’ve told you they are serious about their work. As for the dear Mercedes collector, they all love how the USA-740 has made tune playing life so satisfying!
Common Questions About the USA-740 IN DASH AM/FM for Mercedes
Will it fit my Mercedes without cutting the dash?
This version is built for the Mercedes and is made to fit the factory radio opening. Custom Autosound says its radios fit without altering or cutting the original dash.
Is there a CD or Bluetooth upgrade?
Yes. The options include Single Slave CD.
What features does the USA-740 have?
You can pick from multiple LCD colors to match your gauges, with a dimmer, and it fully controls the optional CD-1 player. The AM/FM RDS tuner holds 25 presets (15 FM, 10 AM) and can auto-store the strongest stations.
Will it work with a 6-volt system?
How does the USA-740 handle phone audio and connections?
There are two auxiliary inputs, a front mini jack and a rear RCA. Custom Autosound rates it at 300 watts peak, and it adds hi-volt 4-channel RCA pre-outs plus a subwoofer line-out.
Can I buy speakers and an antenna at the same time?
Add-ons offered here are a front dual voice coil speaker, a rear 6x9 speaker pair (Custom Autosound 6x9 Speaker Pair and Upgraded Pioneer Speaker Pair), and a hideaway antenna.
USA-740 specifications
- Bluetooth built in (streaming and hands-free calling)
- 300 watts peak power (45W x 4 RMS, 2-ohm stable)
- AM/FM stereo tuner
- 2 AUX inputs (3.5 mm front and RCA rear)
- USB port
- Direct control for optional CD-1
- 5-channel RCA pre-outs including subwoofer pre-out and control
- 15 FM and 10 AM presets
- 7-color LCD with dimmer; RDS station/song/artist display
- DSP EQ; auto-store presets
- Electronic tuning and volume; separate bass/treble; 4-way fader; L/R balance
- Power antenna lead; digital clock
- USA/EUR/JAP/RUS tuner capability (USA default)
- Custom Autosound 2-year manufacturer warranty
USA-740 wiring and tech tips
Use this as a head-unit reference for power, ground, antenna, speakers, and amplifier connections. Always match the printed diagram that ships with your unit if it differs.
Power and ground (typical Custom Autosound harness)
| Function | Wire color |
|---|---|
| Ignition / ACC +12V | Red |
| Battery / constant +12V | Yellow |
| Ground | Black |
| Power antenna | Blue |
Ignition and power-antenna leads are commonly fused at 1A on the harness—confirm against the guide that ships with your radio.
Speaker wiring (typical)
| Speaker | Wire color |
|---|---|
| Left front + / − | White / White-Black |
| Right front + / − | Gray / Gray-Black |
| Left rear + / − | Green / Green-Black |
| Right rear + / − | Violet (or Purple) / Violet-Black |
USA-740 extras
Expect antenna, USB, microphone (Bluetooth), CD-1, and subwoofer RCA connections in addition to front/rear line outs. Use the front 3.5 mm AUX or rear RCA AUX for wired sources.
Suggested order for a classic Mercedes
- Disconnect the vehicle battery before any wiring.
- Connect ground first, then constant (yellow) and ignition (red).
- Connect the antenna plug and the blue power-antenna lead if your car has a power antenna.
- Wire all four speakers, matching polarity.
- If using an amplifier, run RCA cables from the front/rear (and sub on USA-740/USA-850) pre-outs.
- Reconnect the battery and test radio, speakers, and charging system voltage.
Tech tips for classic Mercedes
- This radio is sold for the factory Mercedes opening used in classic models—do not cut a modern DIN rectangle if you want a stock look.
- A poor ground is the most common cause of whine or weak audio; scrape paint at the ground point and use a star washer.
- If AM reception is weak, check the antenna mast, cable continuity, and that the antenna plug is fully seated.
- Vintage Car Radio does not install radios. If you are not comfortable with 12V wiring, use a qualified installer.
USA-740 manuals
Download the manufacturer guide for operation, safety, and the official wiring diagram. You can also browse our full library on the Manuals page.
Vintage Car Radio does not offer installation. The manuals are for do-it-yourself reference or to share with your installer.
Two-Year Custom Autosound Warranty
All Custom Autosound radios sold by Vintage Car Radio are backed by a 2-year manufacturer warranty from Custom Autosound.
Radios are checked before shipping. If something is wrong out of the box or under warranty, call us at 844-802-4499 or 574-226-6676 and we will help coordinate with the manufacturer.
Vintage Car Radio does not offer installation services. Refer to the Manuals and Wiring / Tech Tips sections for manufacturer guidance, or use a qualified car-audio installer.
FAQ — classic Mercedes USA-740
Will this fit my classic Mercedes without cutting the dash?
It is built for the original radio opening used on classic Mercedes models. Compare your dash opening and bezel to the product photos. We do not modify dashes in-house.
Does this radio have Bluetooth?
Yes—Bluetooth is built into the USA-740 for streaming and hands-free calling.
Do I need an amplifier?
Many owners run speakers directly from the radio. Pre-outs are there if you want more volume or a subwoofer later.
Do you install the radio?
No. Vintage Car Radio ships the unit and documentation; installation is DIY or by a shop you choose.
What is the warranty?
Custom Autosound radios include a 2-year manufacturer warranty. See the Warranty section for details.
Need help?
Call 844-802-4499 or 574-226-6676.
Specs
Wiring / Tech Tips
Manuals
Warranty
Two-Year Custom Autosound Warranty
All Custom Autosound radios sold by Vintage Car Radio are backed by a 2-year manufacturer warranty from Custom Autosound.
Radios are checked before shipping. If something is wrong out of the box or under warranty, call us at 844-802-4499 or 574-226-6676 and we will help coordinate with the manufacturer.
Vintage Car Radio does not offer installation services. Refer to the Manuals and Wiring / Tech Tips sections for manufacturer guidance, or use a qualified car-audio installer.
