Thinking of embarking on a DIY audio project? Then there is no better choice than a homemade amplifier. You don’t have to spend so much on getting a high-end amplifier when you can easily make one yourself at a much lower cost.
Learning how to make a homemade amplifier is easy and this article will walk you through the process, including: the type of amplifier to make, what you need to build an amplifier, and safety measures to take during and after making a DIY amplifier.
Without further ado, let’s get right into it.
How to Make a Homemade Amplifier
There are several steps to take when it comes to building your amplifier and the first of those is identifying what kind of amplifier you want:
Research the Kind of Amplifier You Want
There are several types of amplifiers and they perform different functions. From amplifiers for headphones to preamplifiers and mono amplifiers, the range is wide. However to commence this project you need some basic knowledge of amplifiers and how they work.
There are 2 major types of amplifiers, namely, the power amplifiers and the weak signal amplifiers. Aside from these two major types, there are other classes of amplifiers – all used for different purposes.
You need a bit of knowledge about these classes to make an informed decision on the best and most effective homemade amplifier to build.
This is first on this list, while they are commonly known as the best quality amplifiers because of design and reduced signal distortions they are not the best choice if your amplification needs are based on high power. This is because they produce heat and seem to lose power carrying current.
These amplifiers do not produce a lot of heat and generally come with a higher efficiency making them the best choice for professional uses, however, they can be difficult to find.
These amplifiers are a hybrid of both A and B classes. They give a higher efficiency rate than class B and do not have the typical crossover distortion issue.
This class of amplifiers is perfect for maximum amplitude and comes with a high-efficiency rate. The quality and crossover distortion of this class are equally perfect. The only downside is how pricey it tends to be.
These amplifiers have an efficiency rate as high as 95% and can be pretty lightweight. The downside to this class is that the sound quality varies depending on the type of speaker used.
The Best Homemade Amplifier to Build
Now that we know about the different and most common classes of amplifiers, let’s go into the best DIY amplifier to build. This amplifier is known as the Chipamp or Gainclone and is the best option when it comes to homemade amplifiers.
The Gainclone is the most common DIY amplifier because it is easy to build with basic components or essential components. It was first designed in 1999 by 47 Lab and there have been several variations over the years, most of which are homemade.
Typical characteristics of the Gainclone include point-to-point construction, premade PCBs, and a physically short feedback loop. They also produce high-quality sound even though they are chip-based.
The Gainclone amplifier we will be building is a class AB amplifier that uses either an LM3875 or LM3886 chip as its main component.
Purchasing The Parts
Once you have an idea of exactly the type of amplifier you intend to build and for what purpose too, the next step is purchasing the best components that suit this amplifier.
When it comes to buying the parts you have to choose either price or quality, the whole point of a homemade amplifier is mostly to save money but you have to be careful not to end up with cheap parts that won’t last more than a few uses and especially because the Gainclone does not require a lot of components.
Categories to be considered are amplifiers, casing, connectors, and power supply. When purchasing these components you have to make sure all components minus the casing are compatible with each other.
Premade amplifier boards can be purchased from sites like Amazon from prices as low as $10 to as high as $200. These boards cut across different ranges of output impedance, operating voltage, and output power amongst others.
Some people prefer to build their own amplifier boards from scratch and this is not a bad idea too especially if you have free time. It also requires value calculations and expertise.
The amplifier chip for Gainclones has mostly two types, the LM3886, and the LM3875. The LM3886 edges the LM3875 as the most preferred option due to several important reasons including:
- It produces a higher amount of output wattage
- It includes thermal and mute features
- It is a high-level performance audio amplifier
- It maintains a high level of signal to noise ratio
The LM3886 is available in 2 units, the LM3886T and the LM3886TF. The differences between them are not much but worthy of note.
The LM3886T contains a conductive plate and generally requires a smaller heat sink. You cannot combine two of these on one heatsink without the use of an insulator and nylon rings.
While for the LM3886TF you can mount two pieces on one heatsink without the need for an insulator.
The first connector to be purchased should be the RCA connector. This is used to carry the audio signal from the rear end of the amplifier.
A lab connector is a 3.5mm audio jack that looks like that of an earpiece to connect your phone to your amplifier. You would also need a male and female 3way XLR splitter cable to transmit the sound signal with minimal loss.
This is commonly more expensive than the amplifier. The actual output power is the most important factor to consider and while high numbers might seem enticing it might turn out as overkill for your amplifier and is never the best option, especially for homemade amplifiers.
Picking out a casing for your homemade amplifier is the easiest part and mostly down to personal choice. DIY amplifier casings can be made from wood, cardboard tube, or aluminum.
The schematics of a homemade amplifier is basically a wiring diagram of the amplifier. You should have a model of what you want your amplifier to look like before you begin purchasing parts or building one.
This is where you determine what type of casing you want and which is suitable for which part. Do note that while it may seem exquisite, wood is not always a great choice when it comes to housing audio equipment. Aluminum is a much better and safer option, although cardboards can be considered for casings too
Most Gainclone amplifiers are built without a PCB, this component basically accepts and boosts the signal from the amplifier through a tube that combines it with current from the power supply.
This means you have to make your own circuit diagram of the amplifier and where you want the power supply and inputs. Make sure no component is interfering with or disturbing the other.
If you’re unsure of how to build your own schematics, here’s a simple resource to follow and you can modify to suit your needs.
Assembling The Power Supply
To assemble the power supply you need is not a difficult step especially when you have the right tools. There are also a few steps to keep in mind when building this component such as:
- Make use of a 1.6 AT fuse on the primary side of the power supply’s transformer
- Confirm that you purchased the right transformer, you can consider the toroid transformer with double secondary windings. The transformer VA rating should at least be 120 VA max output with the secondary voltage between (+/-)18 volts and (+/-) 24 volts
- Learn how to properly wire your transformer and make use of tools like a wire stripper and a wire cutter
- Use a color system for all your wirings. It makes identifying it better and easy
- Avoid using capacitors
- Make sure all the parts supplying the primary voltage are insulated. For metal casings, ensure that your wires are not coming in contact with the casing
- Check that all your wirings are in place
- Plug your power supply unit and measure the voltage on your output connector making sure the plus and minus voltage values are the same
Building The Amplifier
When it comes to building the amplifier, you have most likely never built one and this is your first project. There are quite a number of helpful tips for you to follow to make the assembling process simple, fast, and completely enjoyable.
- Study your circuit diagram well enough to understand what you intend to build, how each component works, and where and how to connect them
- Use a color system wiring such as black to black wires
- Make use of the right-sized heat sink
- Confirm that the amplifier chip is insulated from the heat sink
- Check that the capacitor to pin is correctly inserted as it is quite common for newbies to make mistakes with this
- Ensure that your wires and lead-outs are kept as far away from each other as possible
- Learn how to properly wire circuits, especially when you have to ground wire
- Get some soldering gloves and protective glasses if you would be making your own point to point connection
Wiring and Connectors
This part is where the actual work lies and it is important you get this process right. If you purchase a ready-made PCB then it’s an easier process and it mostly comes with a user manual on how to assemble and connect it.
You can also get more help on how to make your own homemade printed circuit board here.
- Note down which part goes where on the circuit board
- Make sure the power supply unit and amplifier boards are properly connected and housed
- Make sure to use correct plugs for the PSU and DC connection
- Build your amplifier and power supply unit section on an open board. This gives you ample space and room to properly monitor your connections
- Figure out how much voltage and power current your amplifier needs as too low or too high a voltage will affect the general output of the amplifier or cause audio distortions
Start off this process by ridding your component leads of oxidation, to do this just use some fine-grit sandpaper. This guarantees a better solder joint and better electrical conductivity. Be careful not to ruin the audio amplifier circuits.
Make use of some glue during the soldering process to hold the components better.
Casings are important because they keep the printed circuit board and wires contained. They are also useful in mounting the power cord as well as the input and output.
Casings made from metal are usually the best option, this is because they help to keep out interference caused by cell phones, light bulbs, or radios.
You can also custom make your casings from a cardboard tube or cardboard box depending on your level of expertise or order a premade aluminum board that fits your size needs. Remember to drill some holes for your RCA Jack and binding posts.
Once you have your amplifier casing ready and your board in place, you can then wire your components together making sure to keep the audio input wire away from the signal ground wire to avoid interference.
Do note you would be working with voltages that have the potential to injure or kill you. Kindly take the necessary safety precautions and avoid live circuits. Follow the steps included in the manual to the letter and make sure you work on a flat surface.
As you can see, building your own amplifier from scratch is not as daunting as you would expect.
So, what are you waiting for? We have covered all the steps on how to make a homemade amplifier, including the components to buy and how to use them to create the best budget guitar amps.
Your homemade amplifier should produce good sound with a deep bass guaranteed you follow the right steps.
If you don’t want a hassle of building your own amplifier, then check our list of the best amplifier for your needs.