Question Adding Headphone Jack to Amp?

[GC64]

So I have an audio amplifier that I hooked up my system's audio to. It is this one:
http://m.ebay.com/itm/272313994576

All of the wires have been hooked up to their proper places. So now, how can I hook up a headphone jack to this amp as well? I have an idea where the left and right audio pins would go, but I'm not sure where the headphone switch pin would be wired to. Thanks

 

[Luke]

Someone else verify, but I'm fairly certain this is all you need to do:

By default, your internal speakers will be on, but when you insert a cable into the jack, the switch is made mechanically to route the audio to your headphones instead of your internal speakers. There is no "switch pin", at least not on this amp.

 

[cheese]

Yep, that looks right

 

[GC64]

Someone else verify, but I'm fairly certain this is all you need to do:

View attachment 1372

By default, your internal speakers will be on, but when you insert a cable into the jack, the switch is made mechanically to route the audio to your headphones instead of your internal speakers. There is no "switch pin", at least not on this amp.

I love that diagram! By "switch pin," I meant the two pins that switch the audio from speakers to headphones. I'm using a psone screen headphone jack, the pinout is this attached. Do I just leave headphone switch untouched?

 

[Luke]

Do I just leave headphone switch untouched?

No, I believe that the psone screen's use of a headphone jack is different, in that it actually does have a signal from the jack to the audio amp that says "hey, headphones are plugged in, so turn the speakers off and turn me on".

I don't know the internal pinout of a psone screen headphone jack but I believe that it can be repurposed for your amp and wired similarly to what I have shown in the diagram I made.

 

[GC64]

I just got the time to try this out, and there is a little problem from where I've gotten so far. I'm using a regular 3.5mm jack (not the psone). All I've done so far is wire the two grounds together and lead them to the headphone jack, also the left and right audio. When turning on (even without headphones plugged in) all I hear are little clicks for the audio. I believe the problem was wiring the two grounds together. Are the two grounds able to be wired to normally?

 

[cheese]

Are the two grounds able to be wired to normally?

Check for continuity between the headphone port ground and power ground

 

[GC64]

Check for continuity between the headphone port ground and power ground

Headphone port's ground and 5v power's ground are not connected. I think the issue is that the two headphone grounds are connected. Is there any way around this or are they supposed to be connected? Just doing what the diagram did.

EDIT: I think I might be misunderstanding the diagram. Are the parts with the arrows part of the headphone jack? If so, that would mean the jack has 5 pins on it when mine simply has 3. I'm using this:

 

[Luke]

Correct, that jack has no audio switching capabilities. You could wire your wires to a jack AND internal speakers, but when you plugged headphones in the speakers wouldn't turn off.

 

[GC64]

Correct, that jack has no audio switching capabilities. You could wire your wires to a jack AND internal speakers, but when you plugged headphones in the speakers wouldn't turn off.

That makes sense. I still haven't solved the first issue though, that being the two grounds wired together. I tried what you said (wiring to internal speakers AND a jack) but i still get the tapping sound. The speakers work up until the point where I wire both grounds together to the headphone jack, then it stops working. Is this supposed to be wired together like this, and if not is there a way around this?

 

[Luke]

I promise you, grounding both the speakers to the same common ground is not the problem.

Post a picture, if you can. Sounds like it might be some other wiring issue.

 

[GC64]

Here are some pictures. Kind of hard to see because of the tight wiring..

 

[Luke]

I'm not certain that that jack you are using isn't a mono jack, do you by any chance have a link to where you bought it, or perhaps a pinout?

Regardless, it looks as though whether it's mono/stereo, the pin you've wired ground to isn't the actual ground of the jack.

EDIT: Yeah, that's definitely a mono jack. The longer pin of the jack you have connected to ground is actually the audio in, and either one or both (not sure) of the shorter pins are the actual ground.

For future reference, this is this the layout of the channels of a stereo headphone cable:

So, if you plug headphones into your jack and the left audio part of the plug doesn't make contact with what you believe to be the left audio part of your jack, that tells you that you don't have the correct jack, or at least you don't have the correct understanding of how to wire the jack.

 

[GC64]

I'm not certain that that jack you are using isn't a mono jack, do you by any chance have a link to where you bought it, or perhaps a pinout?

Regardless, it looks as though whether it's mono/stereo, the pin you've wired ground to isn't the actual ground of the jack.

EDIT: Yeah, that's definitely a mono jack. The longer pin of the jack you have connected to ground is actually the audio in, and either one or both (not sure) of the shorter pins are the actual ground.

For future reference, this is this the layout of the channels of a stereo headphone cable:
View attachment 1413
So, if you plug headphones into your jack and the left audio part of the plug doesn't make contact with what you believe to be the left audio part of your jack, that tells you that you don't have the correct jack, or at least you don't have the correct understanding of how to wire the jack.

Well I semi-fixed it. I tried it out with a psone headphone jack and got the same results. Out of curiosity, I turned down the volume and the audio sounds normal again. So for some reason when I wire the headphone jack, the speakers wont work at high volume (makes the tapping sound). If the jack isn't wired up, it works fine at high volume. Any possible explanation for that?

P.S. the headphones work fine too, but it also makes the tapping noise at high volume just like the speakers.

 

[Luke]

You have it wired up but without headphones plugged in, and it changes the performance of the speakers? No, I have no explanation for that.

Not sure what to tell you, maybe another picture will help. As I said above, I believe that psone screen audio jacks are a bit different, in that they bridge the switch pins. I have not messed with them before, and I do not know whether they can be made to work for other applications (my hunch tells me they can but I just don't know).

 

[GC64]

You have it wired up but without headphones plugged in, and it changes the performance of the speakers? No, I have no explanation for that.

Not sure what to tell you, maybe another picture will help. As I said above, I believe that psone screen audio jacks are a bit different, in that they bridge the switch pins. I have not messed with them before, and I do not know whether they can be made to work for other applications (my hunch tells me they can but I just don't know).

May be a problem with the audio amp itself, but I can't speak too much to that issue either.

Well I didn't mess with the switch pins, just the other three. right now both the speakers and headphones play. Here's a video with the setup and the audio. Also, I switched out the speakers for psone speakers and got the same result.

 

[Luke]

Sorry I can't be of more help.

Reading about your amp online, it seems to be pretty tiny, works best with 4ohm speakers and max 3W output per channel, and doesn't have much of a protection circuit; it says powering it without speakers connected can damage it, or reversing polarity can damage it, etc.

But, maybe it isn't a problem with the amp, and if it isn't, hopefully someone else can come in here and know what's going on. Good luck!

 

[Madmorda]

I would hook up your speakers to a male headphone jack as the audio input, then plug it into your phone and go to YouTube. Use a stereo sound test to make sure that your audio board actually IS stereo. I pulled three audio amps out of various speakers, and they all turned out to be mono despite saying they were stereo. I checked out your eBay link and didn't see anywhere that it specifically said it was stereo.

It could also be your headphone jack or wiring. There are some see-through ones on eBay, just search "switching headphone jack." That would make wiring easier since you can visually see how they work. I can't speak to their quality, but they're cheap so at least you could use them for testing.

Also, when you plug in your headphones, they get super loud because they receive the same power as your big speakers, so turning it down may affect their functioning.

 

[Fiskers1208]

I would hook up your speakers to a male headphone jack as the audio input, then plug it into your phone and go to YouTube. Use a stereo sound test to make sure that your audio board actually IS stereo. I pulled three audio amps out of various speakers, and they all turned out to be mono despite saying they were stereo. I checked out your eBay link and didn't see anywhere that it specifically said it was stereo.

It could also be your headphone jack or wiring. There are some see-through ones on eBay, just search "switching headphone jack." That would make wiring easier since you can visually see how they work. I can't speak to their quality, but they're cheap so at least you could use them for testing.

Also, when you plug in your headphones, they get super loud because they receive the same power as your big speakers, so turning it down may affect their functioning.

I am not sure if you realize that the audio amp he's using is stereo. on the PCB, there are two Speaker outputs. so yeah.

-merge posts-

Headphone port's ground and 5v power's ground are not connected. I think the issue is that the two headphone grounds are connected. Is there any way around this or are they supposed to be connected? Just doing what the diagram did.

EDIT: I think I might be misunderstanding the diagram. Are the parts with the arrows part of the headphone jack? If so, that would mean the jack has 5 pins on it when mine simply has 3. I'm using this:

I don't like to bump old comments but here is a headphone jack that you can use. https://www.amazon.com/3-5mm-Stereo-Panel-Mount-Jack/dp/B000ML4A2Q

also, you can use a spdt switch to turn on, or off the speakers


Moderator note: please stop double posting, there is an edit button for a reason.

 

[Madmorda]

I am not sure if you realize that the audio amp he's using is stereo. on the PCB, there are two Speaker outputs. so yeah.

Like I said, I bought several that appeared to be stereo and were labeled stereo but upon testing were not. They had input for both left and right audio, and had places to solder both left and right speakers. One appeared stereo like that, but actually had the speakers wired in series. Another one only outputted (left or right I can't remember) to both speakers so that actual stereo sound would have half the sound it should.

A quick stereo check would rule these things out