50 years of car amplifiers
Car audio power through the decades
Car amplifiers have gone through plenty of changes since they first hit the scene in 1973. Back then, car amps were bulky and their specs were a bit wimpy compared to what’s available today. But those underpowered giants of yesteryear laid a solid foundation for the high-tech amps we enjoy today.
Some of the earliest car amplifiers featured in the Crutchfield catalog
Humble beginnings of the car amplifier
We started carrying car amplifiers in 1976, just three years after Jim Fosgate created the first car amps in 1973. While they could be small, most were much larger than modern amps that offer similar power specs. One of our first offerings was the Craig 9230A. It boasted a mind-blowing output of 12 watts per channel and had no onboard controls to speak of. For a bit of perspective — today, even the most cost-effective aftermarket car stereos dish out anywhere from 14 to 22 watts RMS. I think that stark difference is eye-opening...and a little bit hilarious.
The Pioneer AD-320 amplifier from 1978 offered up a little more power, clocking in at 20 watts, and it was fairly compact. But, despite those positives, it also lacked any onboard controls. Advancements in amplifier technology have made form factors smaller while increasing output power.
A standout example of amplifier evolution is AudioControl’s ACM-4.300. This 4-channel amplifier is nearly the same size as that vintage Pioneer, and can be mounted almost anywhere. It pumps out 45 watts per channel, which is more than enough for most entry-to-mid-level aftermarket speakers. The ACM-4.300 also offers subsonic filters, high-pass filter controls, level controls, and line-level and speaker-level inputs.
Keep it classy
Amplifier classes are some of the most misunderstood concepts in car audio. An amplifier’s “class” refers to which design method it uses to turn electricity into audio power. Without getting too much into the weeds, what you need to know is that all amps fit into one of four different classes. The class designation more or less tells you how efficient and clean an amp’s power output is.
Classes go, in order of least to most efficient: A, B, AB, and D. But how do they all compare?
Class-A amplifiers
Class-A amps were some of the first. They’re still around but are difficult to find, expensive, and never used in car audio. As amplifier tech evolved, things got smaller and more efficient. That meant more power, less heat, and less current draw.
Class-B and AB amplifiers
Class-B amps weren’t liked by many due to issues they had with distortion. The hybrid amp class, AB, was the only choice if you wanted to get a cool-running, high-fidelity, full-range amplifier to power your speakers. That is, until Class D came along in the ’90s.
Class D amplifiers
They’re the most efficient, lightweight amps available. When Class-D amps were introduced, they were only used for bass due to their pesky high-frequency distortion. But their tech has improved significantly, and these days they sound fantastic no matter what they’re powering.
If you’re dying to know more about amplifier design, read our article about amplifier classes.
Kenwood Excelon XR901-5 5-channel amplifier: connections side and controls side
Extra channels to power more speakers
Long gone are the days of being limited to only two channels of power. Back in the day, you’d have to run multiple amplifiers to drive your system, and even then, you’d likely have to bridge one of them to get decent power to a subwoofer.
All that extra work isn’t necessary these days. Modern 5-channel amplifiers, like Kenwood’s Excelon XR901-5, are well-rounded do-it-alls, with four full-range channels dedicated for car speakers, and the final channel used for powering a subwoofer. That gives you a single, central location for all speaker and power connections and simplifies the install.
Dialing in your vehicle's sound
Not only are modern amplifiers smaller, more efficient, and more powerful, they’re also more controllable. With vintage amplifiers, you’d almost always have to run outboard crossovers if you wanted any sort of frequency cutoff — that went for subwoofers, too. These days, amps have high-pass or low-pass filters (or both), depending on what they’re being used to power.
Lately, manufacturers also have been adding digital signal processors (DSPs) to their amps, giving users more control and customization than ever. DSPs offer users powerful methods of controlling their system. Often, amps with DSPs let you tweak everything from individual speaker filters, speaker EQs, and time alignment.
The cool thing about DSP-enabled amps is you don't need a screwdriver or other tool to manually adjust knobs and dials to get the sound the way you want it. Most are controllable from your smartphone or laptop and let you hear the tweaks you're making in real time.
The JL Audio RD400/4 amp has clipping lights that help take the guesswork out of tuning an amp
It's all about setting the gain
The gain setting on an amplifier is one of the first adjustments you'll make, and it's the most important thing to get right. Adjusting the gain changes the input sensitivity of the amplifier and matches it with the output level of the receiver it's connected to.
You don't want it set too high or too low. If the gain is too low, you'll hear electrical and background noise in the signal. Too high and you'll cause the signal to clip and your speakers will distort. There's a fine balance that needs to be achieved.
If you'd like to learn the ins and outs of setting your amp's gain, check out our article on how to tune a car amplifier.
Setting the gain on an amp has often been considered a chore. You need a keen ear for distortion, and have to play music or test tones and listen for the signal to start clipping. Some audiophiles go a step further and use special equipment to measure current, then do complicated math to get the best results. But now, some new amps simplify things with clipping lights that tell you when the gain is set too high and there’s distortion in the signal.
Amplifier placement flexibility
In years past, you were limited on where and how you could mount your amp. Many popular amps were large and bulky, so if you drove a compact car that didn’t have a lot of real-estate, squeezing one in was a potential nightmare. You had to give them lots of breathing room to dissipate the heat they generated, lest they burn up. And you couldn’t mount them upsidedown due to the heat, since warm air rises, and all that heat would be soaked up into the circuit board.
Modern amps are far more flexible and forgiving. Though they still need room to breathe, Class-D amplifiers don’t need nearly as much as older amps. That means you aren’t as limited on amp locations. Have a good place underneath your seat to mount an amp? Go for it. What about a spot underneath your dash? Do it. Your amp will be right at home.
One of our self-made amplifiers. The aluminum cooling fins on the top kept it nice and cool.
We once sold our own amps!
If you were one of our customers during our early years (thank you, by the way!), you likely saw our very own Crutchfield-branded amplifiers. We started making them in the ’80s to give our customers another option for car audio amplification, and we made a valiant effort to have them stand out. Our amps were popular with our customers, and had impressive signal-to-noise ratio and power output specs for the time. Our amps were large (go figure), but they had super nice aluminum cooling fins that kept them cooler than most amplifiers of the time.
Need any help?
When it’s time for you to add more power to your sound system, check out our Car Amplifier Buying Guide.
Our knowledgeable and friendly Sales Advisors are standing by if you're looking to pick up a new amplifier. They get hands-on with a lot of the cool gear we carry, so feel free to reach out. Also, every Crutchfield purchase comes with free technical support throughout the life of your gear.
_mobile.jpg)
Comments (0)