Whether you’re looking for a speaker setup at your next event, or are talking about how your favorite guitarist sounds so good, if you have even a passing appreciation for audio you will no doubt know something about amps.
However, these often-overlooked bits of kit are the lifeblood of sound playback, and whether you know it or not, you have almost certainly had to use one at some point. But what is an amp, what does it do, and what’s its realtionship with the audio interface?
Do you need both, or will just one suffice? Let’s find out.
Table of Contents
What is an Amplifier?
Music, when reproduced through a speaker, is created via a time-varying voltage – also known as a signal. The more voltage you have the higher the signal, which in turn means that the audio being played back is louder.
An amplifier is at its core a circuit built to take the input signal and output a higher voltage version. The factor by which it increases the signal is determined by the user in most instances – typically using a gain dial.
However, while this may seem like the start and end of amplification, in reality there is a whole lot more to it than just gain. Rarely if ever do these devices increase signal gain transparently, instead leaving the audio with a particular color or tone.
Initially, due to analog technology such as tubes, valves, and transistors manipulating signal as they increase it, amplification has become an art in itself with producers and engineers seeking out particular amps and favoring particular them due to their unique audio coloration.
Nowadays amplifiers are sold based on their idiosyncrasies, and in the digital era, analog modeling and finer control over audio color means that producers can tune their sound to be precicely how they want it. Whether it’s sparkling highs, a booming bass, or warm mids, each amp has its own merit and character that must be learned in order to be deployed with maximum efficacy.
Amp-mania extends to podcasts as well as music, as anyone editing a recording will know that vocal processing can make or break a show, at worst making your show all but unlistenable, or at best pushing your sound to new heights. Therefore, like it or not, amps are an integral part of any podcasting setup.
Is an Audio Interface a Pre-Amp?
An amp is a great tool for boosting a signal, but amplification works in stages. While for a guitar or any other line level signal, the signal is loud enough on it’s own to be amplified with little issue. For mic level signals (which are significantly lower in level initially) a standard amplifier runs the risk of ruining the quality of the input audio.
Enter the pre-amp. As the name suggests, before an amplifier boosts the signal through speakers, a pre-amplifier boosts a weaker signal to the line level. This stage is critical in the amplification process as pre-amps focus on boosting the signal to a lesser degree while keeping the audio as close to the original as possible.
An audio interface typically to mediate between signal and amp, so, is it a pre-amp? It depends. Most audio interfaces do offer a preamp built in, so that users can boost the signal to line level for recording and playback through a speaker, however, an interface offers much more than just it’s pre-amplification. The primary function of any audio interface is infact to convert audio signals into digital signals readable and recordable by computers.
In this way the device is interfacing with the computer, allowing the audio to pass through. However, it is very common for there to be a gain control included, which uses an internal pre-amp to boost signal levels.
As this isn’t their primary function, some people opt to use external preamps to boost the signal prior to input. This is more of an investment, but the luxury of a separate preamp is that you can take control of your audio and ensure it is of the highest quality prior to power amplification.
So, while an audio interface may certainly include a pre-amp, they serve a much more important role than simply being a gain-boosting solution.
Is an Audio Interface the Same as an Amplifier?
Audio interfaces are not the same as amplifiers, and to understand why it is important we get to grips with the part each plays in the signal chain.
As covered previously, interfaces may pre-amplify, boosting a weak signal to line level, at which point the audio is converted into digital format for recording and production, etc. When outputtin the audio from the computer, the interface will then convert the digital audio back to analog signal with the express purpose of being put through a power amp.
Amplifiers are purpose-built to facilitate a much larger scale signal boost than is standard with most consumer audio interfaces. So, if you are playing audio through speakers, you will need a dedicated amplifier unit to achieve the best quality audio possible at a decent monitoring level.
Counterintuitively, amps and audio interfaces have a secondary difference. As mentioned earlier, guitar and bass amps have distinct colorations that make them of particular interest to musicians. This is a different type of amp that is positioned at a different point in the signal chain.
These amps are placed prior to pre-amplification, and in these circumstances, the amps are handling line-level signals, so no pre-amp is required. In this circumstance, the amp is giving the sound a new tone, which is captured via the computer, so the amp must sit before the interface. However, if you are listening through speakers, an additional amp will be necessary to give the recorded signal the strength to be played back.
Do I need an Amplifier if I have an Audio Interface?
With all this in mind, it should be apparent that an amplifier is necessary along with an audio interface. Fundamentally, these are two separate processes, that require two separate pieces of gear to handle each stage well.
Some people suggest also investing in an external pre-amplifier, as again, this is ensuring one piece of equipment is used per process and gives you much more access to tone shaping pre-audio to digital conversion, but most interfaces come with preamps as standard – which is a much more cost-effective option for those of you on a budget.
By now the function of both the audio interface, and the amplifier should be apparent, and it should be evident why both are essential in your podcast production suite. While each bit of kit may seem to do one very specific task, they all serve an incredibly important role in making your audio the best quality it can be, and in combination, you will soon find your equipment becomes a formidable force that equals far more than the sum of its parts.
But this is just the tip of the iceberg when it comes to amplification, and there is much more to learn about each step of the process. We didn’t have time to properly cover the ins and outs of pre-amplification here, but if you are eager to learn more, we have it all covered in ‘Is a Cloudlifter a Preamp? Our Thoughts’