Universal Earbud/Headphone Volume Control

So I bought a PMP (Portable Media Player) from Hong Kong so i could play my NES games with the on-board emulator wherever was convenient. Long road trips, flights, waiting rooms, etc. are places that I like to kill time with portable media but the only trouble was that the on-board emulator only had one volume......MAXIMUM. My earbuds of choice didn't have adjustable volume so i needed a solution to turn the game music down a little, I ended up coming up with the 3.5mm Earbud/Headphone Volume Adjuster.

Note: Turns out I'm not the only one with this idea, I did a quick search on Youtube and found this tutorial! I was even able to find a few commercial versions of this idea out there but they were $10-20.

Step 1: Tools & Materials Needed

Materials you will need:

- Safety Glasses, Safety First!
- 3.5mm Male Stereo Audio Jack
- 3.5mm Female Stereo Audio Jack
- Small gauge Stereo Audio wire
- 1Kohm Thumbwheel Audio Potentiometer for Volume Control
- Heat Shrink Tubing
- Solder
- Solder Sucker or Braid (in case of emergency)

Tools you will need:

- Hot Glue Gun
- Soldering Iron
- Wirestrippers
- Heat Gun (optional - you can use a soldering iron to carefully melt heat shrink)
-Digital Multimeter to test connections (may only need it if you have issues)

Step 2: Secret Places to Get the Parts You Need!

To find the parts you need you may not need to look any further than from your junk electronics pile or an old PC. If you can't find anything there you could ask  a neighbor or friend if you can raid their pile or they may even have may have some parts just kicking around. The following is a list of specific places you might look for the parts you need:

3.5mm Female Stereo Audio Jack

- Discman
- Walkman
- Stereo or Boombox
- PC Modem board
- PC sound card
- PC CD/DVD drive
- Portable Radios
- Motherboards
- Automobile Head unit

3.5mm Male Stereo Audio Jack

- Headphones
- Earbuds
- 3.5mm Stereo extension cable

1Kohm Thumbwheel Audio Potentiometer

- Pair of old headphones with a volume control potentiometer (if you can't find an old pair you can always buy some cheap ones on ebay for $2-3)
- Mouser (this style will only work for one channel so you will need 2)
- Digikey (not sure if this one is logarithmic or not)
- If you find any other places to find these please let me know because my resources are tapped

I learned a very valuable lesson while testing salvaged thumbwheels out of old electronics -> these thumbwheels control the gain of amplifier chips and are not suitable for direct (in-line) volume control. The thumbwheels I salvaged from CD drives were 50Kohm and the ones I salvaged from Discmans were 10Kohm. The value needed for this project is only 1Kohm and as it turns out they are much harder to find then I thought.

If you cannot possibily find the other parts anywhere for this particular project, then as a last resort you could always go to your neighborhood Radio Shack (The Source by CC in Canada) or order online surplus parts from places like Electronic Goldmine .

Step 3: Shortcut Already?

SHORTCUT!

Here's some advice that ended up saving me tons of time and it probably will for you as well if you can find an old set of Headphones with built-in volume adjust. So take your old headphones (mine had a loose speaker connection) or a pair that are just a faux pas in today's fashion world and rob the volume adjust from them. Cut the connection as close to the speakers as possible to keep the length of your project as long as can be. Then strip back the rubbery insulation to expose the audio channel wires as well as the, usually copper, ground sheath. Now skip ahead to Step 5!

Diagram Abreviations:

CHL - Left Audio Channel
CHR - Right Audio Channel
GND - Copper sheath around both channel wires which makes the Ground connection

Step 4: Thumb Wheel Method

So if you simply cannot find a set of headphones with volume control to salvage all is not lost, there is always the Thumb Wheel Method!

Friendly Reminder: Place those Safety Glasses on before you start soldering to save your eyes from potential magma hot, rouge solder splashes.

Find a Male 3.5mm audio plug with some wire left on it, cut the wire where you'd like the pot to go. Now grab your Thumb wheel and solder all the Ground sheaths together and then onto the left most pin (Pin 1). Next solder the the Channel (CH) wires from the male jack to Pin 2 for CHR & Pin 3 for CHL, then the output wires going to the female jack will be respectively soldered to Pin 4 for CHL & Pin 5 for CHR.

If you're curious about the Thumb Wheel Pin-out, here's what I found online: With the Thumb wheel facing up and the 5-pin edge facing toward you. From left to right, the pins are:

1) Common (GND for audio use)
2) R1 Wiper (Out 1 for audio)
3) R2 Wiper (Out 2 for audio)
4) R2 End (In 2 for audio)
5) R1 End (In 1 for audio)

Now would be a good time to measure to use you Digital Multimeter on the Ohm setting the potentiometer values, a value range of around 0-1Kohm for each channel is what we are looking for.

NOTE: In my diagram I have the inputs and outputs swapped but since the Potentiometer is being used in a variable resistor configuration it doesn't matter if they are swapped. (It was easier for me to draw the diagram that way :D )

Solder on your male stereo jack and extra bit of audio cable to the pot (as seen in the 5th picture) and you should be on your way to the next step.

Step 5: Attach the Final Connector

Now Solder from the output side of the Volume Control Pot to the Female 3.5mm jack.

Remember:

CHL connection corresponds to the tip
CHR connection to the Middle band
GND connection to the Largest band.

A little food for thought about Audio potentiometers; they are actually not Linear in operation but Logarithmic. Our brains actually interpret sound Logarithmically (that's why hearing tests are measured in Decibels) so the resistance of the volume control must be adjusted Logarithmically in order for the variance in volume to sound smooth to our ears.

Step 6: STOP.....Give It a Test

STOP....don't proceed any further until you Test er' Out. You don't want to make any permanent/semi-permanent  adjustments to you project until you know it's working just in case there might be a loose or broken connection somewhere, or you've wired up you channels on the wrong pins of a connector....I'm speaking from experience here, these things happen :).

Grab your favorite music player and see if those tunes will indeed make you bounce.

Some possible Issues you may face:

- Your music player of choice is not working, try another
- You've accidentally swapped the order of CHL & CHR on the inputs or outputs
- A solder joint has come loose somewhere
- One of the audio jacks you've used is too long or too short to make the proper connections, try pushing/pulling your connections a bit in fine increments
- You may have a Thumbwheel that is too high in resistance or is bad

Do not proceed to the next step until all is good, you may need an Ohmmeter to help you out.

Step 7: Ok You're Good, Put Some Final Touches on It

Now that everything is working add some hot glue on the connections of the Female connector to protect the wiring and solder-joints from being damaged. Then take out some of your favorite colored heatshrink tubing and seal up the business end of your project.

Step 8: The Metal Will Live On!

Plug-in your Earbuds or Non-volume adjustable Headphones and Rock and/or Roll with your newfangle volume control!

Comments

[bqbowden]

I have a headset without a mute for the microphjone ... how can I add a button to do that?

[robin.davey.ca]

It was great that you suggested getting the parts from TheSource (canada). When I went to find a pot I found a Nexxtech Inline Volume Control for $0.96 + 12 cents tax. Saved myself a lot time.

[jboulianne]

Awesome! Do you have a picture or link that you could share?

[robin.davey.ca]

You can find it here:
https://www.thesource.ca/en-ca/cables-adapters/audio-cables-connectors/other-cables-accessories/nexxtech-inline-volume-control-cable/p/108069758

They are also on AliExpress.com for about the same price but shipping alone is 3+ times the price adn takes at least 30 days.

[UnfinishedDD]

Thank you for this very nice instructable! I like the thumbwheel. This gives you the possiblity to have the volume just right, while with pushbuttons, you have to choose a preset volume level (1,2,3,...) and cannot choose one in between 2 levels.

[Applesinnamon123]

i know this post is dead, but what if i used a 10k pot for the volume control? how would that effect audio signal? there arent ant 1k pots locally and ordering online for one is my absolute last resort

[Botmatrix]

Naw this post isn't dead, it may have been popular for a little while then it faded into obscurity, but like any instructable it's still here as a resource and I still support it. Anyway, to answer your question, yes you can definitely use a 10K pot BUT you will not have a very large volume range, you will quiet the volume a lot quicker. Oh yes, and know that a regular linear potentiometer won't work well for adjusting volume, your pot will have to have what's called a Audio Taper or Logarithmic Taper. Sorry, but you most likely have to order online Audio taper thumbwheel pots aren't common.

[Botmatrix]

So for those curious about the Media Player I'm using you can find more info by by checking out eBay or Dealextreme.

I found mine on eBay for $40 but they are now just over $20 for the 4GB version. At DX it's a little bit pricier (and only 2GB) but ordering from them is a sure thing.

Some cool features are: Voice recording, NES emulator, Low MegaPixel Camera, Video & audio play back (with volume adjustment that works :D ), Slide screen, Rechargeable internal Battery & Expandable SD memory card slot.

Cons: Buttons click very loud - don't play on an airplane unless you like people angrily staring at you, NES emulator volume cannot be adjusted (with the version I own), & with the Power Button you have to hold it down for a while to turn the unit on and off.

Thank you all for your interest!

[MrL33TPenguin]

I just got one from my aunt's co-worker and I've been wondering, have you been able to put some movies onto your PMP yet? Much help please? ;D

[PSPerson]

OR you could just put CFW on your PSP and play all sorts of emulator games there =] jus' sayin.

[Botmatrix]

Thanks for the suggestion but I've done that as well. I found that while the PSP does emulate pretty good it's got minimal extra functions. It does have WiFi and video/audio playback but the browsing experience is quite clumsy and it's clunky to use as an mp3 player. I guess all I'm saying is that with the Pandora it meets most of my needs (wants) with a seeming limitless set of options/extras and hopefully the hardware feels better that my PMP. Its got the best of both worlds + Dual Analog Nubs :) !

[PSPerson]

nice. any android device could also work. nesoid, snesoid, gameboid, and the like are pretty good.

[sqeeek]

Nice instructable, I love the PMP too, lol. Amazing how cheap that thing is. How's it work? Is it worth your $35?

[Botmatrix]

Well hard to say if it's worth the cash, cause I intended it to be my all-in-one portable media solution but the user interface (UI) was sub-par and I was so disappointed with feel (and unresponsiveness) of the buttons that I didn't ever use it. All I use it for now is an MP3 player so if you are willing to spend ~20-40 bones on a 4GB MP3 player then I'd say yes it's worth it.

Since I purchased my PMP I've moved upwards and onwards and have pre-ordered a new all-in-one solution (without Camera, but doubles as a netbook) which is the Pandora.

Actually it's funny that while researching for a great media player/emulation device and wanting something with more functionality than the PSP and better quality hardware than my PMP I ended up finding many better PMP/emulation devices. I came across other cool handhelds like the Dingoo and Wiz, but eventually found and fell in love with the Pandora (well i guess the concept since I'm still waiting to receive the hardware).

[Optical10]

Funny you should mention the "PANDORA" as a friends son was invited to help assembly the first batch & was offered a unit. Maybe you could have a working holiday to the UK?

[sqeeek]

Dang, wish I got those kind of invitations. Lucky kid ;)

[sqeeek]

Ooh, looks cool. I might just give that a try :D Hmm... I wonder how hard it would be to build one? I have a lot of old PPC and WinCE device parts... and some old game controllers... hmm... Maybe use old laptop or netbook parts? *has a new project to try*

[Win7Maniac]

Good to know the PMP still lives, and the iPod hasn't completely taken over. At least I'm not the only one still using them now! ;P Great 'ible

[shepnstein]

I've never heard of a PMP. That's cool that it can do NES emulation. If the hardware isn't fun for playing NES games (loud clicking, etc.), consider using a flash cartridge for the Gameboy Advance. NES Emulation on the Gameboy Advance works perfectly and the button layout is just like the old NES controllers.

[Botmatrix]

Quite ironic, I actually did consider doing that but eventually found out about the Pandora (see comments below) and decided to put all my eggs in one basket instead of investing in other products. I forgot to mention that the Pandora can emulate N64 and PS1 and almost every console pre-dating them. With all this interest in portable media players maybe we should start an Instructables group on the subject?!?!