3.5 MIC to USB Conversion - Page 1
Forum section: electronics / beginners

author: vidarr
author_rank: Frequent Contributor
timestamp: January 15, 2025, 11:51:18 pm
content: After searching around for some time, I cannot find a way to convert my external mic with a 3.5 jack to USB. There are many other options and versions, but not like what I have.Essentially, I just want to cut the end of the mic cord (cut the 3.5 jack off) and re-wire it to a usb connector so I can plug it into my laptop.I know the pinouts for the USB, but I don't know which wires of the mic go where.In the pic, you can see the 3.5 jack for the microphone. It just has one band, so it must be the audio and a ground? But, the mic also has an on/off switch. How does it get its power?Sorry if this is super newbie, but I never worked with mics before. (I did do research before posting this. I just don't get it.)Thanks!edit: Mic is aiwa DM-H15 IMP600 OHM

author: special_K
author_rank: Regular Contributor
timestamp: January 16, 2025, 12:10:29 am
content: You can wire anything to anything, doesn't mean it will work...USB is a computer bus. At each end something "smart" exists, be it a full computer or some microcontroller, who can hold an intelligent conversation. "Hello I exist", "what are you?" "I'm a keyboard", "okay, I will listen for typing from you, and sometimes I will tell you to light up one of your LEDs when capslock is on".A microphone with a 3.5mm plug is nothing like that. It cannot say hello in USB language, it has no brain inside.What you want is a USB sound card. You plug your microphone into that box, then plug the box into the computer.

author: Benta
author_rank: Super Contributor
timestamp: January 16, 2025, 12:34:41 am
content: At $10 for this one, it doesn't get much cheaper or smaller:https://www.amazon.com/QianLink-External-Headphone-Microphone-Mic-Supported/dp/B0DDCCC7RH/ref=sr_1_20?sr=8-20No affiliation.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 16, 2025, 04:14:34 pm
content: I cannot order parts right now, I am in the middle of Brazil. But, my laptop also has a 3.5 audio, headphone/microphone jack* that I can use (was in use for speakers, but I can use BT instead to free up the jack).The laptop 3.5 jack definitely works for speakers/headphones, but *I don't know for sure if it supports a mic in. Usually, I can find a decent video on YT, but all I find are junk videos lately.Thanks!

author: abeyer
author_rank: Frequent Contributor
timestamp: January 16, 2025, 06:50:14 pm
content: The vast majority of modern laptop 3.5mm connectors are of the TRRS variety to support headsets with microphones... I'm sure there are exceptions to that, but they are exceptions.So, it most likely supports microphones, but you can't typically just plug a plain microphone in without an adapter, it's designed for headsets with both mic & speakers. The adapters to do this are easy to buy... but if you really can't and need to wire it yourself, the TRRS wiring is standard, but depending on the type of microphone, though, that side is more variable. You'll need to adapt whatever your mic output format is to the TRRS mic connections.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 16, 2025, 07:03:50 pm
content: Excellent! This is good news. The mic is an aiwa DM-H15, but I haven't been able to find a pinout for it. I have the pinouts for all the 3.5 jacks already (TRRS, TRS..), just not the mic.I have an old headset with mic that I can cut the cord and rewire to this mic. Then, I can keep my amped speakers by using the headphone wires, and rewire the new mic to the mic wires.Man, I hope this works.THANK YOU!

author: themadhippy
author_rank: Super Contributor
timestamp: January 16, 2025, 07:17:42 pm
content: Quotetip is signal and the sleeve is the ground.

author: Zero999
author_rank: Super Contributor
timestamp: January 16, 2025, 09:24:20 pm
content: If I remember rightly, you need an electret microphone to work with a sound card. A dynamic microphone won't work.

author: Analog Kid
author_rank: Super Contributor
timestamp: January 16, 2025, 09:31:25 pm
content: Quote from: Zero999 on January 16, 2025, 09:24:20 pmI don't believe that's correct, but I could be wrong.Sound card don't supply phantom power, so the electret would have to supply its own.

author: SteveThackery
author_rank: Super Contributor
timestamp: January 16, 2025, 09:51:56 pm
content: Quote from: Analog Kid on January 16, 2025, 09:31:25 pmIt does - if 5V counts. The PC standard microphone jack is mono with 5V on the ring.

author: Analog Kid
author_rank: Super Contributor
timestamp: January 16, 2025, 09:56:49 pm
content: Quote from: SteveThackery on January 16, 2025, 09:51:56 pmAh, so. Sure, 5V counts, even if it's not 48V.Pretty sure either dynamic or electret mikes would work.Heck, maybe even a crystal mike*, depending on the mike input's impedance.*not very well, though.

author: Zero999
author_rank: Super Contributor
timestamp: January 16, 2025, 09:59:46 pm
content: I've tried a dynamic microphone with a sound card and it didn't work. My current microphone is just an electret capsule on the end of a piece of cable, connected to a 3.5mm connector.

author: wasedadoc
author_rank: Super Contributor
timestamp: January 16, 2025, 10:01:45 pm
content: Quote from: Analog Kid on January 16, 2025, 09:31:25 pmRight and wrong!You do not need an electret mic to work with sound cards. The vast majority of consumer sound cards do not supply "phantom power" in the true sense* but the vast majority do supply "plug in power".* phantom powering uses three wires. One is ground. The other two have balanced audio and (both) have +48 Volts (or sometimes lower such as +24).Plug in power needs just 2 wires. One is ground. The other is a few volts (typically between +3 and +5) from the card and audio from the mic.

author: themadhippy
author_rank: Super Contributor
timestamp: January 16, 2025, 10:14:36 pm
content: Quotetry raising the gain,used a 58 many a time on a pc

author: Analog Kid
author_rank: Super Contributor
timestamp: January 16, 2025, 10:17:11 pm
content: According toSteve Thackery's post, the tip is the input to the sound card without any power, so that should work for a dynamic mike.

author: Zero999
author_rank: Super Contributor
timestamp: January 16, 2025, 10:31:57 pm
content: Quote from: themadhippy on January 16, 2025, 10:14:36 pmI tried that and it didn't work. Even with the gain all the way up, I had to put the microphone right near my mouth and shout for it to work. I did think about using a transistor amplifier powered from the electret mic bias provided by the sound card, but decided it was much easier and simpler to get an electret mic.

author: Analog Kid
author_rank: Super Contributor
timestamp: January 16, 2025, 11:41:35 pm
content: Sure it was a dynamic mike, and not a piezo (crystal) one?Or maybe the plug wiring was wonky?

author: Zero999
author_rank: Super Contributor
timestamp: January 17, 2025, 09:31:25 am
content: Quote from: Analog Kid on January 16, 2025, 11:41:35 pmYes, I know it was a dynamic, because I had opened it up. I would have expected a piezo to have worked because it has a higher output.The wiring was fine because I tested it.

author: SteveThackery
author_rank: Super Contributor
timestamp: January 17, 2025, 09:42:55 am
content: Quote from: Zero999 on January 17, 2025, 09:31:25 amExcept piezo microphones require a very high impedance input. The PCB standard microphone input is very low impedance for a piezo mic.

author: magic
author_rank: Super Contributor
timestamp: January 17, 2025, 10:01:04 pm
content: Quote from: Zero999 on January 16, 2025, 10:31:57 pmYou do realize these statements are mutually exclusive?It works, but sensitivity may be unsatisfactory. Make sure to crank up the gain and enable "mic boost" (more gain).In reality, even common dynamic headphones work as a mic if you plug them into a mic jack.Regarding wiring, there are two options:1. If the laptop has TRS jacks, connect the dynamic mic between T and S.2. If the laptop has a TRRS jack for HP/MIC combo, connect the dynamic mic between R2 and S because T and R1 are HP outputs.

author: Nominal Animal
author_rank: Super Contributor
timestamp: January 17, 2025, 10:29:45 pm
content: Quote from: magic on January 17, 2025, 10:01:04 pm(Or, to put another way, the tip is left audio output, first ring right audio output, second ring is ground, and sleeve is microphone signal.)

author: magic
author_rank: Super Contributor
timestamp: January 17, 2025, 11:26:52 pm
content: Or vice versa and R2 is MIC and S is GND. Welcome to the wonderful world of TRRS headsetsI suppose the laptop jack may be hardwired one way or another, but often both lines are routed to a special chip which tries to guess what sort of thing is connected and ground the appropriate terminal. Some audio "codec" chips maybe even have the functionality built-in. And if you get it wrong, you have no ground in your headphones and both sides play the difference between L and R.

author: Analog Kid
author_rank: Super Contributor
timestamp: January 17, 2025, 11:35:10 pm
content: I think my old MacBook is like that; if you jiggle the headphone plug or pull it out and replug it in, it takes a second or two for the audio to come back, so some kind of automagic stuff is going on there.

author: themadhippy
author_rank: Super Contributor
timestamp: January 17, 2025, 11:50:34 pm
content: Quotehafler headphones,cool.

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2025, 04:47:38 pm
content: Quote from: magic on January 17, 2025, 10:01:04 pmPedantry aside, I didn't wire the dynamic microphone up. I just used the pre-wired connector and it was unusable, so I swapped it for an electret and it worked perfectly.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 19, 2025, 01:56:31 am
content: Well, I am still working this out. Why oh why do Mics have to be so simple and complicated at the same time... Seems like mics are a pretty hot topic.So, I actually went back to EEV YouTube video where he talked to the mic designer/engineer that I can't remember his name. He drew some really good mic and op amp circuits.Someone is bringing me one of those tiny USB soundcard with 3.5 jacks.Thanks Guys for All your Input!

author: special_K
author_rank: Regular Contributor
timestamp: January 19, 2025, 05:02:39 am
content: Your link does not work. It just sends us to a login page that also advertises a sale or promotion of some sort.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 23, 2025, 04:02:57 pm
content: My friend brought me this external soundcard that I thought would allow me to use this mic with my laptop, but it isn't working.The laptop recognizes the device; I can play audio through it just fine; it sows up in the Win10, so-called "Sound Control Panel"; the mic does not work.I tried my headset with mic and it works.Could it be because of this 3.5 jack? It only has two rings, tip and sleeve. Most of the 3.5 mic jacks I see online are TRS. (I know what the rings are for. TS, TRS, TRRS..., I just don't know what else the problem can be. This should work.)Any ideas? Thank You!

author: magic
author_rank: Super Contributor
timestamp: January 23, 2025, 04:47:48 pm
content: It's possible that the tip and ring are shorted internally, so this plug shorts them both to ground. This appears to be the case in my "GeneralPlus" USB audio dongle - the dongle records in mono and when I plug headphones into the mic jack, both sides work equally so they seem to be shorted.You could take the dongle apart and cut this connection. Or make a cable with TRS plug and TS or TRS socket and leave the ring floating. Or reterminate the mic with a TRS plug with floating ring.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 24, 2025, 12:22:53 am
content: The tip of the mic jack appears to be the mic audio and the single sleeve is the ground. I'm going to make a homemade adapter where I send the tip of the mic cord to the 2nd ring of a TRRS jack, and the ground to the sleeve.From what I have read so far, computers and phones have TRRS jacks. So, this is what I have to wire the mic to conform to. Not really a problem, just so ridiculous to have to do.Let's ditch the 3.5 jacks and go with USB. Professional audio can keep the 1/4 jacks and XLR; audiophile equipment can keep their RCA and banana jacks; everything computer/phone related should be USB. 3.5 jacks are ridiculous. Really stupid at this point.Thanks!

author: magic
author_rank: Super Contributor
timestamp: January 24, 2025, 12:55:18 am
content: Hmm, if your dongle's tip and ring contact are shorted, things may also work if you insert the plug halfway:Code:socket: T R Splug: T S

author: radiolistener
author_rank: Super Contributor
timestamp: January 24, 2025, 01:23:31 am
content: Quote from: SteveThackery on January 16, 2025, 09:51:56 pmThere are two mic pin-out standards for 3.5mm connectors and they are not compatible:PC microphone:Phone/Camera microphone:Headset connectors also have two standards:

author: vidarr
author_rank: Frequent Contributor
timestamp: January 24, 2025, 08:40:22 pm
content: OK, so I salvaged some 3.5 jacks and wires and am going to attempt to make this mic work on the laptop.You cannot see the red wire on the mic cord, but the red wire of the mic goes to that red wire on the cord with TRS jack.The black wire of the mic will go to the ground wire of the cord with TRS jack.The jack is wired such that the tip and ring are going to the red wire.The sleeve is going to the ground.Then, the TRS gets plugged into the external soundcard/dongle, which plugs into the laptop via USB.Will this work? IDK... I hope so.Thank You!edit: I was trying to make this simpler radiolistener. LOL.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 24, 2025, 08:46:03 pm
content: Quote from: magic on January 24, 2025, 12:55:18 amI tried this but it didn't work. Fortunately, the mic screen easily unscrews so I could check its wires. The only thing I don't know is if the mic needs 5v on the red wire from the usb dongle, or if the 5v is even provided. I don't know how the laptop jack is wired. I did not open up the soundcard/dongle either.

author: Analog Kid
author_rank: Super Contributor
timestamp: January 24, 2025, 10:27:20 pm
content: Since the mike clearly says "cardioid dynamic", it definitely doesn't need any power, assuming there's no circuitry in the handle (and there shouldn't be). So you just need to find the right connections.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 25, 2025, 11:20:51 pm
content: Well, it works. I cut off the mic's TS jack and soldered on a TRS jack. Then, that plugs into the USB soundcard to the laptop. Everything turned out to be pretty straightforward in the end.The sound is really good too. There is no noise, or background sounds. Just very clear vocals coming thru. I will do some EQ adjustments to fine tune it, but I am happy with the outcome.Now, my next questions are coming ----> The DAC hookup.Thanks Everyone for your help!

author: vidarr
author_rank: Frequent Contributor
timestamp: January 25, 2025, 11:21:54 pm
content: Yep, it was pretty simple in the end. Thankfully.