One Amplifier Channel Louder Than The Other
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A common problem with analog amplifiers is that one channel (usually the left channel) may be slightly louder than the other. For some amplifiers, it is more pronounced than for others. However, the problem often goes away when the volume knob is turned high enough. In this article, we will discuss fixes for cases where one amplifier channel is louder than the other.

There are a number of possible fixes for one amplifier channel louder than the other. This includes boundary gain/placement fixes, fixing defective speakers, adjusting levels or balance, and cleaning dirty controls. 

Below, we dive into details about each fix and how you should approach the troubleshooting process. 

Quick Troubleshooting

Before we dive into tackling this problem directly, we need to perform some checks and balances to ensure we are going about the process in the most efficient way.

amplifier channels unbalanced

Here are the quick troubleshooting steps to take before getting into anything more complex:

  1. Ensure a problem actually exists: First of all you need to confirm that the issue truly exists and that it’s not just your ears. Sometimes, the issue maybe with one of your speakers for example. To check that you really have an actual issue, you can use a wattmeter. With a watt meter, you can do a balance test. Of course, you can use a multimeter to do this as well. Keep in mind however that stereo recordings are not the best way to check balance. Instead, get some sort of mono source like some mono video on youtube. Use a combination of the wattmeter/multimeter as well as listen carefully to the system. A system without an issue will have the music nicely centered between the two speakers.
  2. Check if you have a balance issue: If the sound is not even, maybe you just have a balance issue. Simply adjust the balance until you find the sweet spot. In fact, you can get even more detailed with this. You can run pink noise to the left then right channels and then measure with an SPL meter at your listening position. While checking the measurements, you can then make any needed adjustment to the balance. 

If the above didn’t work, the following are various methods that you can go about fixing the problem.

1. Speaker Boundary Interference Response and Speaker Placement

Speaker Boundary Interference Response or SBIR  is a term that describes how the proximity or closeness of a speaker to a boundary such as a wall changes the speaker’s response or sound quality.

Speaker Boundary Interference Response

This especially affects the bass response and can cause an effect where one speaker seems louder or more powerful than the other. 

If you have one speaker in closer proximity to a wall than another, you should make sure that you position each speaker at an equal distance from the walls.

Aso, is one leaned back/forward farther than the other? Are they the same height? Ensure each speaker is setup exactly the same in terms of alignment.

You should also toe-in your speakers. Toe-in is the process of pointing a speaker inward toward the listener rather than aiming it straight ahead. You should always toe in both main speakers and not just one. 

Doing so not only equalizes boundary interference but will improve your overall soundstage as well. 

You should note however that boundary interference can be a complex issue because it can happen even if distances are the same, but the right and left walls are constructed differently or made from different materials.

Also, keep in mind that the discrepancy will vary across the frequency band (e.g bass is affected the most). 

 

2. Adjust One Speaker Level and Balance

As we mentioned in the quick troubleshooting tips, adjusting levels is very important as it is one of the key culprits that will cause your system to sound unbalanced. 

speaker channel level adjustment

The quickest way to do this is to turn the level down on say the right speaker a bit until things sound even.

In fact, you can even adjust your speaker levels to account for positioning issues if you don’t wish to adjust your speaker’s placement.

For example, let’s say your right speaker is closer to a side wall and sounded slightly lower than that the left channel. All you need to do is to raise the right channel output on the receiver or amp until things even out. 

Please note however that adjusting the balance can often just be a bandaid for the problem since you haven’t fixed the underlying issue.

Remember, adjusting the balance doesn’t make the bad side louder. All it does is to make the good side drop out a bit so things become even.

 

3. Defective Speaker – Swap Out Speakers

One of the more obvious issues here may be that one of your speakers is bad. If you have an extra speaker lying around, especially an identical one, swap it out for the speaker that seems to be defective. 

Before you swap out the speaker though, you can check speakers with a multimeter and make sure they’re reading the proper impedance. If one side has higher/lower impedance than the other, then that’s possibly your issue. This is especially important if you have passive speakers connected to the amplifier because they will pull all their power from the amplifier. 

Remember impedance determines how much current is pulled from the amp and so you can have problems if, for example, you use a 4-ohm speaker with an amp designed to power 8-ohm speakers.

Speakers are different impedances aren’t always interchangeable. You can read more about 8-ohm speakers vs 4-ohm speakers to get an idea.

In fact, swap out the cables that run to the speaker as well. Is there a noticeable difference after the swap? If it’s not the speakers or cables themselves, it is a headunit or signal issue.

 

4. Dirty Controls and Knobs

Another common culprit is dirty controls and knobs. Balance and volume controls operate exponentially, meaning small variations in resistance between right and left channels don’t make much of a difference. 

However, dirt can cause this resistance to increase quite a bit.

electric grade contact cleaner for cleaning amplifier pots

To find out if this is your problem, you can do some testing. All you need to do is to use a mono switch and a different source with a different cable to power each speaker separately.

If the difference between the left and right channels is reduced, then a dirty control is the likely culprit. 

How To Clean Dirty Controls and Knobs

You need to clean every switch and control on the amp. A lot of controls and knobs can affect balance besides the obvious balance and volume controls.

This includes the tape monitor, tone defeat, stereo/mono selectors, speaker buttons, volume pot, input selector, level sliders, etc.

To clean each knob, spray your cleaner so that it gets in the crevices, and work it thoroughly. This means you need to remove the cover casing and work internally while spraying into the holes inside of the pots and switch mechanisms.

To ensure the spray gets into the crevices of the knobs, you can even tilt the amp on its side or tilt it face up or down to let gravity help flow along the cleaner. Be sure to place paper towels underneath to catch the excess flow.

Which Spray Cleaner Should I Use To Clean Contro Knobs?

Go for a good cleaner such as Deoxit D5 or Deoxit tuner spray and you can even follow up with Faderlube on the rotary pots.

You can use Deoxit 5 on the switches and contacts as well. You can also use some of the RS branded tuner sprays. You can also use Electric Grade Contact Cleaner, especially for the POTs.

You can find all of these sprays on Amazon. Here is a link for theDeoxit D5.

If you need more detailed instructions, use the Deoxit tutorial that comes with the product as a guide. 

5. Defective Switch or Control

Sometimes your switches and controls may not just be dirty, but defective. You can detect this type of issue by adjusting the knobs and then seeing how the amp and speakers react.

For example, let’s say you turn the volume control all the way down, but the amp volume on the display doesn’t budge and the speaker’s volume is unchanged, then this control is likely defective and you need to have it replaced.

This is especially likely to happen if the volume knob is a regular old potentiometer. Pots often degrade over time. They get a bit dirty with age and may stop working altogether after a while. 

 

6. Faulty Cables or Headunit

Poor audio due to faulty cables is a common cause of distress in the audio world. To test this theory, start by switching the RCA plugs on the back of your amplifier.

Faulty Cables or Headunit amp channle unbalanced

If one channel is still louder and you already confirmed that the speaker itself is not the issue, then the issue is the amplifier.  

Here are some quick troubleshooting steps to check if the issue is with your cables or headunit:

  1. Check ALL connections.
  2. Swap the old RCA’s with new reliable ones. Of course, if the problem goes away then your RCAs were faulty.
  3. If the problem still persists, check headunit output voltage with a multimeter. Use the AC voltage setting on the multimeter and probe one channel on the RCAs. You will need to consult the amp spec sheet for the proper output voltages. If the voltage doesn’t read your listed prevoltage for the headunit, then the issue is the headunit.
  4. If everything above checks out, you likely have an issue within the amp itself. Test the AC voltage from the amp. If it’s too low, you may have a defective capacitor.

 

7. Defective Capacitor

Electronic component-wise, a defective capacitor is a common problem resulting in unbalanced channels.

Defective Capacitor in amplifier

It is common for an electrolytic capacitor to fail. It simply dries up, causing the capacitance to increase which then means the cap will require a greater voltage to charge up which then lowers the total power output at that channel. It could also affect the frequency response of that channel.

If you are comfortable with power electronics, you can disassemble the amp and check if any caps are defective. You can use a multimeter with capacitance measurement to do this. 

 

Issue Only Occurs At Low Volume?

If the issue only occurs at ow volume, the problem is likely the very design of the volume control.

It is rather common to find stereo volume controls with poor tracking at low volume. Normally, this is how the controls are designed and you can’t fix it. Your only option is to get a new control.

 

Conclusion

We have discussed various ways to troubleshoot and diagnose the rather annoying situation of having one amplifier channel louder than the other. Whether it is the left channel louder than the right or the other way around.

Follow the methods as laid out, step by step and we are confident you will find the culprit and a good solution to fix it. Good luck!