Headset Left Right Volume Mismatch

[Airmaster23]

Hi,

I have a used Lightspeed QFR solo headset (http://www.lightspeedaviation.com/content/lightspeedaviation/CustomPages/QFR-Series.htm).

I can hear fine out of the left ear, but I can barely hear out of the right. With the engine running, I cannot hear out of the right ear.

I bought a 1/4" female to 3.5 mm female adapter so I test the headset on my computer. If I use a jack that puts out a lot of volume, I can get decent volume out of the right (but I need to turn down the left because it's so loud). However, with a jack with only so-so output, I can barely hear in the right ear.

Does anyone have some suggestions for me?

Is there a way I could re-wire the control box so it's just mono?

Thanks.

 

[Archammer]

It is already wired for mono and stereo (mono by default). On the top, front of the volume block, there is a Stereo/Mono switch. Make sure that is on Mono, and it may correct the issue.

The issue in the computer, depends on the adapter more. IF the headset is on stereo or mono and IF you have a "1/4" STEREO jack to 3.5mm stereo adapter, you should hear in both ears with either setting. IF you have a "1/4" mono to 3.5 mm mono, and the headset is on stereo, it will only play in the left ear. Set to mono to correct.

IF that fixes the problem, and you still want to mess around with wiring it for mono only; Open the volume control block, disconnect the lead from the stereo/mono switch and run the green and yellow to the left volume control tabs. (This will bypass the right channel volume and stereo/mono switch)

That will not fix your problem though, if the stereo/mono switch didn't fix it.

If there is still an issue with the audio in the right ear after flipping the switch, then you have an issue with a broken right speaker, right volume control or overhead cable connection. Tracing that would involve some deconstruction.

 

[BigBadLou]

Shane to the rescue again!

 

[weirdjim]

Here is a quick test to make a determination. Get a flashlight battery (AAA through D, it doesn't matter {*})

Hook one end of the battery to the long metal shaft of the 1/4" phone plug. A temporary hold in place with thumb and forefinger will work.

Momentarily touch the other end of the battery to the tip of the phone plug. You should hear a click or pop in both earpieces and they should be of equal loudness. If not, then you have some more difficult troubleshooting to do.

{*} The only time AAA through D matters is if you are discussing the female mammary apparatus.

Jim

 

[Shepherd]

Silly question: Any hearing loss in your right ear?
I'm asking because a friend asked me to fix a similar problem, but it turned out he had some hearing loss in one ear compounded by ear wax.
After he got his ears cleaned, I built him a 2 channel inline amp with volume controls for each side so he could boost the volume on the one side.

 

[Airmaster23]

Hi,

Thanks for the responses.

My wife and brother have both used this headset as a passenger.

Both said that they could only hear out of the left ear. However, my wife thinks I fixed the problem in the plane (this was last Fall) and then she could hear out of both. However, I couldn't fix it with my brother (flight was 2 weekends ago).

If I flip the mono/stereo switch, it doesn't make a difference, no matter where the volume controls are positioned.

I will try the test with the battery tonight when I get home.

This is the 1/4" STEREO jack to 3.5mm stereo adapter I bought so that I can test the headset at home. It's a 45 minute drive to the airport.

http://www.be-electronics.com/product_p/nys227.htm

I've attached a photo that shows what the control box looks like. In this position, I can't hear anything out of the left ear, and I can just barely hear out of the right ear.

 

[flyingron]

Do both of the sliders feel like they have the same resistance? If you take the battery box apart you'll find that the two "slider" parts match up with the slider part of two variable resistors on the circuit board. Sometimes when these things get jarred the part you see comes disconnected from the underlying slider. It's a little tricky to get it lined up while reassembling, but you'll get it with some determination.

 

[Archammer]

I've attached a photo that shows what the control box looks like. In this position, I can't hear anything out of the left ear, and I can just barely hear out of the right ear.

So from what you've described, and the photo, it sounds to me like you have a speaker in the death-throws. Just turn everything on, and see if you can get a change with the volume slider and the cable.

It's so funny, every time I read this stuff I feel like I need to help like some kind of Headset Man! hahaha

If you want to send them to me, I'll take a look and see if I can fix you up. I've got parts laying around that should work for those old dodgy ear muffs.

Address is on our contact page.

 

[Airmaster23]

I tried the battery test.

There is a pop in both ears, but it is definitely louder in the left ear.

If I leave it connected, there is a hum that is louder in the left ear than in the right.

I will take some photos of the battery box tonight to help out in diagnosing this problem.

The volume sliders will work at changing the volume in each ear, but the right one is proportionally much quieter than the left.

Do you think the problem is the speaker in the right headphone or the slider/switch box?

 

[Airmaster23]

Here are the photos of the control box.

From Archammer

"If there is still an issue with the audio in the right ear after flipping the switch, then you have an issue with a broken right speaker, right volume control or overhead cable connection. Tracing that would involve some deconstruction."

Should I start with removing the ear seal to get at the right speaker, or de-soldering the volume component?

Thanks.

 

[Archammer]

Here are the photos of the control box.

From Archammer

"If there is still an issue with the audio in the right ear after flipping the switch, then you have an issue with a broken right speaker, right volume control or overhead cable connection. Tracing that would involve some deconstruction."

Should I start with removing the ear seal to get at the right speaker, or de-soldering the volume component?

Thanks.

Either desolder or just bypass the volume control and wire a lead directly between the two yellows (You can even hold a paper clip to the two outside right solder points of the potentiometer and test). Then plug it in and see if you get full volume in the right side. If you do, the slide potentiometer (volume controller) is kaput. If conditions persist, do you have a voltmeter? Do you want to get into trying some other things? Got a single piece of wire or some cable?

 

[Airmaster23]

There is only 1 yellow wire connected to the PCB.

I have attached a photo with some labels.

I have both a digital and analog voltmeter. I've done some straightforward soldering projects, most recently de-soldering and installing a new MP3 aux jack in my car stereo. (I've never worked with SMT components, though.)

I've never touched a headset before and I don't know how the circuit works. But I do have some equipment (no oscilloscope though), extra wire, etc. and I think you could walk me through it.

Thanks for your help.

 

[Archammer]

I haven't forgotten about you, My honey-do list was a nightmare this weekend, and we finally got our big parts order in.

I will do my absolute best to get you taken care of tonight. Sorry for the wait.

 

[Airmaster23]

Hi Archammer,

I took it to an electronics repair shop on Sunday night.

They think the sliding volume potentiometer is bad and needs to be replaced.

They quoted me $55 for parts and labour. He said if they could source the pot from the US, it would be a quick fix, longer if they needed to order it from China.

The only marking I saw on the potentiometer was B501 and I couldn't find a thing when I looked for that part online.

Do you think there's an easier fix?

Or should I give it a week or two and see what this repair shop comes up with?

 

[Archammer]

Well that's what I wanted to test, and it appears they think the same. If I replaced the volume controls here, it would be about the same price. However, mine are standard round pots because of slide pot issues previously talked about. So your best bet is to just go local.

The B501 isn't a brand or part model number. It actually delineates the type and resistance. So that is a B(=Linear taper) 500(=ohm) 1(=1/2 watt) slide potentiometer. If you desolder the bad volume control there might be a model number on the base of the pot PCB. Let me know if you do that and what you find. If you decide to do the following, don't bother with desoldering anything.

If you don't care about the mono/stereo, then forget replacing the parts. Wire the right side (+) leads to the one good volume control (move J1 to J5 & move W1 to W4), and done. Always keep the switch on mono. Costs you about 30 minutes of your time and $.20 worth of solder. I will tell you that as many things are, when you have pairs of things, they tend to go out close together. So if the other slide shyts the bed, then you're back to replacement.

Whatever you decide to do will work out, and I'm here if you need anything.

 

[Airmaster23]

...

Wire the right side (+) leads to the one good volume control (move J1 to J5 & move W1 to W4), and done. Always keep the switch on mono.

Archammer, Sorry for the delay. I have been pretty busy the past couple months and I finally got around to working on the headset.

I moved the wire at J1 to J5 and W1 to W4.

However, now I don't have any audio (or noise whatsoever) in the right ear. The left one still works fine.

Before I made the switch, I could hear out of the right, but at significantly less volume than the left.

What should I try next?

Thanks.