What is A Preamplifier?
There are plenty of definitions of an amplifier which we can write. But we want to deliver an analogy so it'll stick with you.
A preamp is like steroids for audio equipment. A steroid enhances testosterone and makes it easier to recover and gain muscle. The end goal for someone who uses testosterone is for someone to get stronger.
The way a preamp compares to steroids is it strengthens signals. That's its whole purpose. One common example of this is when there's a microphone.
Sometimes a microphone has a weak signal. For it to be functional, it needs to be the same signal strength as the other audio equipment. The preamp is used to boost the signal of the mic. It's also used for the audio equipment in question to be noise-tolerant.
Once the signal has been strengthened, there are 2 things which could happen. One, the signal could be up for further processing, or, it could be transferred to an amplifier.
Why Is A Mic's Signal Weak?
As we've mentioned already, mics have low level signals. But why?
There are 2 reasons why. The microphone input and the line-level input. The microphone input is built for a microphone's capability. A line-level input on the other hand is much stronger.
To paint a picture of the difference in strength between signals, a line-level signal is about 1 volt which is 1,000 times stronger than a microphone-level signal.
Now you know why a preamp is needed. Making up that difference in voltage can't be done with adjustments. You need actual equipment (preamp) to bridge the gap.
What Does A Preamp Do For Home Audio?
A preamp for a home audio system isn't much different than what a preamp does for a mic-level input.
One fact you might not know is a preamp for home audio is "active" rather than "passive." Being active means it boosts the signal to an amplifier.
The real question is if you actually need a preamp for your home system. This question depends on different variables.
A speaker system differs from a home theater system for obvious reasons. Both can be used for home audio, but what you need to create each system differs.
The more devices you need for your system means the more you need a preamp. A preamp is a great choice for a system with a lot of devices because it can be your command center.
A couple more things it could do is control your volume and connect your devices.
What Do I Need To Watch Out For When It Comes To Preamps?
One thing to look out for when it comes to preamps is noise. You want a good signal to noise ratio.
To maintain a good signal to noise ratio is to make sure noise is totally, or mostly eliminated before deploying a preamp.
If a preamp is added when there's noise still there, the amp will just amplify the noise and make it worse for your listening ears.
Another factor to look out for is deciding whether you want an active or passive preamp. An active preamp is more expensive, but more dynamic sonically. A passive preamp is the exact opposite. Less dynamic and cheaper.
Why Should You Get A Preamp?
There are 4 reasons why you should get a preamp.
1. It can mix signals
When a sound engineer goes into the studio to polish a song up, one of the first things on the to-do list is to mix the song.
This is done to make sure everything sounds smoothly when you hear the song. A preamp can mix signals into one to make sure output also goes smoothly. If a preamp wasn't there, the different types of voltages messes with the audio quality. Different voltages creates static.
2. Adjustments
A preamp also helps to adjust sound. Besides being able to mix sounds, you can adjust how your audio output is.
If your stereo sounds like it has too much bass, or it's too screechy, your preamp can come in and fix it.
3. Signal Boost
We already explained this with the microphone analogy in the beginning.
4. Signal Tune Up
To explain this, let's take the microphone example again because it's practical. A preamp's location is usually next to the audio output source (microphone).
Some microphones come with a built-in preamp such as a capacitor microphone. An amplifier in this situation increases the signal as the signal passes through. It's an autonomous process.
Compared to a dynamic microphone, an amplifier would have much more of an effect because its signal is much weaker than a capacitor microphone. Installing a preamp would be like giving nitrous boost.
What Is An Amplifier?
An amplifier isn't much different than a preamplifier. It just boosts the line-level signal for the speakers. A preamp's responsibility was to get a low level signal to the same level as a line-level signal.
What Is An Integrated Amplifier?
This section could have gone into the preamp section, but oh well. An integrated amp is an amp which has a preamp and a full amp combined into one.
An integrated amp is better than a receiver in some cases. And that case is if you're building a sound system instead of a home theater.
Investing in an integrated amp helps you avoid unnecessary features. It brings in components which you actually need.
Other reasons for getting an integrated amplifier is it takes up less space, saves money, and saves time.
Purchasing one means you don't have to worry about a preamp or main amp because it's all in one package.
What Is An Operational Amplifier?
An operational amp's main function is to make an efficient amp. There are different ways it can do that.
A couple of ways it increases efficiency is to create a desired impedance or increase gain. Their desired outcome is to make sure inputs are all the same simultaneously. The way it makes sure all inputs are all the same is it inserts voltage when one of the inputs doesn't match.
An op amp has 2 inputs and 1 output. The 2 inputs are called non-inverting and inverting.
When it comes down to it, there are plenty of op amps. What you need to understand is all of these op amps have the same goal. But the difference among them is they all have some opportunity cost.
What Is A Vacuum Tube Amplifier?
A vacuum tube amplifier is one of the smaller amplifiers. Their purpose is to regulate larger currents so there isn't too much distortion.
They're also used to increase the voltage of a signal, just like other amplifiers.
One reason vacuum tubes are used as amplifiers is because of a difference in sound. Casual listeners probably don't mind. But audiophiles can hear a distinct difference.
Their distinct sound provides more warmth, similar to a vinyl track.
A con for tube amplifiers is their vulnerability. Tube amplifiers are much easier to break. This is why the best stereo amps have tube rolling as a feature.
Transistor Amplifiers?
A transistor amplifier isn't an actual product, but a transistor acts like one.
A transistor in a circuit acts like an on and off switch. Once the switch is flipped on, more current goes through the circuit.
There are 2 pathways for current to flow through.
The first pathway is the base/emitter pathway. And the second pathway is the collector/emitter pathway.
Even though there isn't a device called a "transistor amplifier", the way it functions makes it look like an amplifier.
What Is A Distribution Amplifier?
This is one you'd use for a sound system for sure. We say this because its purpose is to distribute audio signal evenly and make sure no signal loss affects the distribution to audio devices.
The key to this amplifier is to make sure it's in the middle of the sound system. Before you even think of getting a distributed amp, make sure you test your audio signals first.
You can test this by using a field strength meter for audio output.
Final Thoughts
The preamp and amp itself are similar but differ in some ways. A preamp is brought in to boost a weak signal while an amp boosts the signal the preamp boosted before.
What we've noticed from our research on amplifiers is there's more of a variety compared to preamps.
Just like most devices on the audio market, there's no clear winner because everybody's situation differs.
What we'll say is your audio devices needs an amp. Regardless if you have a home theater system or audio system, an amplifier is prerequisite.
A lot of the usage for a preamp is for instruments and microphones.
The distinction between each is easy to solve. It's all about figuring out what you want from your audio devices. Figuring out how complex your audio system will be is a step in the right direction.
Cases are, if your audio system is complex, you're going to need a distributed amp to spread the signal evenly between each component.
It all starts when you decide what you want.
