How to Test Amplifier without Speakers

Many people use amplifiers with speakers immediately after purchase. And because of their unstable nature, they can burn whatever you are testing them with, including speakers.

An unstable amplifier can burn inadequate loads and even itself. There are very few ways you can test amplifiers without speakers.

However, one of the reliable ways you can test and measure amplifier outputs is with a multimeter. If you don’t want to burn your speaker, use a multimeter to test your amplifier.

How to Test an Amplifier Without Speakers

The best way to test amplifiers without loading speakers is by using a multimeter. Using a multimeter is safer and more cost-effective. It also means your speaker will be safe.

With the proper step-by-step process, you will know how to use a multimeter to test the amplifier’s outputs and see if your speaker is compatible with your amplifier.

If you follow these guidelines, you will know if your Amplifier is stable or unstable.

Step 1: Get a Working Multimeter

The only tool you will need for this process is a multimeter. Go into any store and get a working multimeter. You can let the store owner recommend the best ones and then choose from them.

It is advisable to go for the auto-ranging multimeters since they are more accurate.

After this step, you can now turn the amplifier’s speaker ABC connection to the proper connection.

Step 2: Turn the Amplifier’s Speaker ABC Connection

If you look at your amplifier, you will see its Speaker ABC connection. Place it at C and leave it.

Then place the volume of the amplifier at zero.

When you are sure that you have turned the ABC speaker connection of your Amplifier to the proper connection, the next step will be to put your multimeter in the right millivolts.

Step 3: Put your Multimeter in the Right Millivolts

The first thing to do is to turn your multimeter to DC millivolts. Then put it at 200 millivolts because you need more millivolts to do the testing.

This is usually at the left side of your multimeter. The right side is AC which stands for Alternative Current.

When you are through with this step, you can now test for the relay, which is the primary test for the amplifier.

Step 4: Test for Relay

After you have placed your multimeter in the right millivolts, check the back of your Amplifier and look for the C speaker connection.

There are always two C connections that come with an amplifier, and they are above each other.

For the one above, Take your multimeter and put the black probe on the minus side of the C connection and the red probe on the plus side of the C connection.

If it reads zero or a negative value, that means there is no relay in that Amplifier, and it’s safe to use for your speakers. 

If it reads 40.0, that means you have a 40 millivolts relay on your Amplifier. This value and above should be reduced because they can blow your speaker.

To be sure, Do the same thing for the C connection below. If you get a value of 18.0 millivolts and below, that value is still safe to be used for your speakers.

This is one of the best ways to test power amplifiers without speakers. Power amplifiers come with a high value of relay.

This relay might not be compatible with your speakers, which will inevitably lead to the blowing of your speaker.

Using multimeters will help get a more accurate reading of the relay in your power amplifiers.

Doing this will help you to know whether to reduce the relay in your amplifier to fit your speaker or not.

After doing this, cleaning the knobs and the switches are next.

Step 5: Clean all the Knobs And Switches

After you are done with the test, the final step is to clean all the knobs and switches on your amplifier. There is a tendency that your speaker will still blow if the knobs and switches are dirty.

So, check all the knobs and switches and clean them thoroughly. This will ensure the smooth working of your amplifier.

You can use the guidelines given to test amplifier output with a multimeter accurately. After which, you can now connect your amplifier to your speakers.

If, after doing this test, your amplifier is not working perfectly, there are some issues with the amplifier. There are ways to figure out if your amplifier is not working correctly.

How to Figure Out that Amplifier is Working Properly

A good amplifier ensures you enjoy high-quality music. Amplifiers are used to control how loud you want your music.

What an amplifier does is simple. It receives music from the source, magnifies the music before it’s sent to your speakers.

However, no matter how good it is, an amplifier can break down anytime. From wiring problems to spoiled wires to bad tubes and blown fuses, there is no limit to the issues an amplifier can have.

But there are ways you can know if you need to repair your amplifier;

  • When it refuses to switch on
  • When you begin to hear humming in your speakers
  • When the surrounding sound features begin to sound lopsided
  • When the bass start reducing
  • When the amplifier doesn’t make any sound because the speaker is disconnected
  • When you begin to get distorting sounds from the amplifier
  • When the volume of the amplifier increases itself randomly
  • When the Amplifier keeps blowing fuses

These are some ways you can know if your Amplifier is not working correctly. Most of these problems can be repaired by you, but it is better to seek the help of a professional.

Measuring Frequency Response of an Amplifier

The only way to measure the frequency response of an amplifier is to do a test signal.  In this test signal, we are going to use an Oscilloscope.

An oscilloscope is an instrument that can measure the frequency response of any audio device, including an amplifier.

It has an internal function generator that can receive sign waves from DC up to 20 kilohertz.

These are the ways you can use an oscilloscope to measure the frequency response of an amplifier;

  • Connect it to the amplifier and set all the amplifier controls to flat.
  • Go to the internal function generator and disable the sleep mode.
  • Set the start frequency to 10Hz
  • Then activate the sweep mode and set the sweep mode type to “Up Down.”
  • Set the stop frequency to 20Hz
  • The output of the Amplifier will start being monitored.
  • You can adjust the treble control to max, which will lead to a boost in the high-frequency response of the amplifier.
  • Make a more accurate reading using the spectrum mode, which plots a graph between amplitudes and frequency.

Final Thoughts

To test amplifiers without speakers is not a daunting task. It involves some steps and patience. You can not rush the steps if you want accurate results.

Using a multimeter is still the best way to test your amplifiers to avoid blowing your speakers.

Amplifiers can also develop trivial and complicated issues as you start to use them. Identifying the problems will be the first step to solving them.

After identifying the issues, you can either provide solutions yourself or seek the help of a professional.

Also, if you want to measure the frequency response of your amplifier, you have to know the test signal that you can use to get the accurate frequency response.

However, if you follow all the step-by-step processes and the guidelines given in this article, you will be able to test amplifiers without speakers.