Building an iDevice Guitar Interface Cable
A few months back, I purchased the ultimate unnecessary-but-awesome gadget: the iPad 2.
With the availability of apps like Amplitube, AmpKit, and Garage Band, it’s immediately obvious how this device can be an amazing guitar learning and practicing tool. I’ll talk more about that in another article. But before you can plug in your guitar, you need a special interface…
Before we talk about building our own device, let’s consider the alternative. There are a number of commercial interface products available. The less expensive ones plug in through the headphone/microphone jack like IK Multimedia Amplitube iRig, Peavey AmpKit Link, Griffin GuitarConnect. That’s the type of device we’ll be building. Then there are also the higher quality, more expensive products that have their own A/D converters and plug in using the dock connector- like Apogee Jam, Sonoma GuitarJack, Alesis iO Dock, Line 6 Mobile In and IK Multimedia iRig HD.
In part 1 of this 3-part video series, I introduce the project- how to make your own impedance matching, buffered guitar interface for the Apple iPad, iPod touch and iPhone. These iDevices all share a similar headphone/microphone jack specification, so this circuit should work with all of them.
I’ll show you why a simple unbuffered cable interconnect will sound terrible- because of the significant impedance mismatch between a passive guitar circuit and the iDevice mic jack. Also, the iDevice provides a 2.8V DC on the mic input to drive a microphone preamp, and as you’ll hear, this voltage totally screws up your guitar circuit.
This isn’t intended to be an ultra-high-fidelity interface. But trust me, it sounds good and costs very little. And the principals learned in this simple electronics project are the same as those required to make a guitar boost pedal like the Fulltone Fatboost.
In part 2 and part 3, I’ll explain all the electronics and show you how to assemble the interface.
Here’s some of the things you’ll need:
A 4 conductor cable, like these. Note the tip-ring-ring-sleeve connector:
Also, a female 3.5mm phone jack for your headphones, and a 1/4” female jack for your guitar:
I’ll cover the electronics components in part 2.
Vandebilt
September 23, 2011 @ 4:03 am
Great to view but where’s part 2?
John
September 23, 2011 @ 7:47 am
@Vandebilt – Nice rhyme! 🙂 I’ll upload part 2 today. And part 3 tomorrow.
Chuck
September 23, 2011 @ 12:30 am
Fun because I know how it ends up…..
John
September 23, 2011 @ 2:55 pm
You definitely have the behind-the-scenes scoop.
Like – I shot most of this video in JUNE, and it took me this long to edit it all and tie up all the loose ends. I’m still shooting a couple of overdubs today for parts 2 and 3! I’m such an obsessive perfectionist. It’ll never be good enough- finally, I just have to cut the cord 🙂
-John
DJ1812
September 23, 2011 @ 7:46 am
are the other parts online yet?
JamesHaskin
September 23, 2011 @ 7:59 am
Sweet, now gimme soma dat part 2 😀
7h3p1930n
September 23, 2011 @ 9:24 am
you big tease!
Cant wait for 2 and 3, love your videos!
CoandCaSSTB
September 23, 2011 @ 12:39 pm
I always enjoy your videos. As an electronics major and weekend guitar player, you always have cool projects and things to keep me inspired!
John
September 23, 2011 @ 9:12 pm
@CoandCaSSTB – great to hear, thanks!
guitarran
September 23, 2011 @ 1:06 pm
John Planetz aka Mr Gadget.!
Simple JFET Preamp for an iDevice guitar interface - Planet Z
September 23, 2011 @ 5:59 pm
[…] up on Part 1, it’s time now to get into the heart of the […]
Assembling the iDevice Guitar Interface - Planet Z
September 24, 2011 @ 7:16 pm
[…] the exciting conclusion to the series, following up the intro in Part 1, and the electronics course in Part […]
OVProyect
November 7, 2011 @ 2:00 pm
You’re the man!! 😀
wseeback
November 23, 2011 @ 5:04 am
You are THE MAN John! You must be an electrician at your day job? I’m going to school soon for electrical engineering. EXCELLENT VID!!! A+ Thanks for making vids, and keep ’em coming!
John
December 7, 2011 @ 10:58 am
@wseeback – I’m not an electronics expert- just an enthusiast. I work as a software engineer at Korg R&D, coding the embedded realtime engine inside the oasys and kronos synthesizers.
A POD in your Pad - Planet Z
December 1, 2011 @ 8:02 pm
[…] interface connects to the 30-pin dock, which as I described in my DIY iOS interface project, is the higher-fidelity lower-noise way to get audio into your iPhone/iPad. This is because […]
Sean P
February 21, 2018 @ 12:44 pm
Don’t know if it’s been addressed but how would one go about building an interface for an iPod touch lightning port?
John Cooper
February 21, 2018 @ 12:50 pm
That would be an entirely different and much more complicated undertaking, with D/A converters, etc. Take a look at this x-ray of Apple’s lightning-headphone adapter to get a sense of the complexity: https://ifixit.org/blog/8448/apple-audio-adapter-teardown/
-John
gullywoots
December 4, 2011 @ 2:05 pm
Neat! I wonder if something similar could be built for an android device like the moto defy.
John
December 7, 2011 @ 10:59 am
@gullywoots – if it has a headphone/mic jack like the ipad, with voltage to power electret mics, then you certainly could. Just find the pinout and specs and adapt as necessary. If you do it, please post back and let me know 🙂
lekosiet
December 20, 2011 @ 1:03 am
hey man, i’m definately gonna do this! thanks. just for interest sake, is it only impedance matching it does?(apart from splitting the signal) if so, will a normal D.I. Box match the impedance, if i use the right connectors? it would mean a lot less soldering….
John
December 26, 2011 @ 10:19 am
@lekosiet – it does impedance matching, and buffers out the mic preamp voltage. An appropriate transformer would accomplish the same thing, but I haven’t tried it. Try your direct box and see what happens!
dhan523
January 4, 2012 @ 7:50 pm
I’ve used the 5457 as interface to my laptop but I’m having a hissing sound though. Is there other way to do this? I did connect my output to the laptop mic input and the latency is acceptable but I can’t stand the hissing noise. Thanks in advance John…
dhan523
January 4, 2012 @ 11:55 pm
Not a hissing sound but more of a steady high pitch sound (Like a sound from an oscillator).
Jezha
January 15, 2012 @ 11:17 pm
Hello John, nice tutorial. Very simple. But i can ´t buy mpf102 transistor here. Please how do i select right transistor and resistor.
John
January 16, 2012 @ 12:55 pm
I listed some alternate parts in the schematic at the top of this post:
https://www.planetz.com/?p=1531
J201, 2n5457, 2n5458 will all work. You’ll need to change the source resistor a bit. You can scan through the comments in that post for suggested resistor values that people have tried.
Good luck!
John
Jezha
January 20, 2012 @ 2:49 am
Hi, i used a BF245A transistor and i tried a lot of resistor. Finally i used 560Ohm source resistor. Hope be useful. Thanks a lot for guide
John
January 20, 2012 @ 9:23 am
Thanks for letting us know!
Happy to hear you got it working.
-John
Dustin
March 3, 2012 @ 10:53 pm
Can I replace the MPF102 with a 2SC1815???
Dustin
March 3, 2012 @ 11:01 pm
Also, Can this damage my Ipod at all?
John
March 4, 2012 @ 2:13 pm
Anything’s possible, but I’d guess it’s unlikely you’ll damage your ipod.
-John
John
March 4, 2012 @ 2:12 pm
For this project, better to use a JFET.
-John
paulo
March 9, 2012 @ 12:14 am
Hi, I want to build a pickup for my acoustic guitar and connect to my ipod then to my stereo. I was thinking using a piezo transducer, should I use this circuit as a preamp? Can you help me?
John
March 20, 2012 @ 10:26 am
I haven’t tried it, but I suspect it may work fine. It’s very simple to prototype and breadboard – try it and see how it goes!
-John
michael
April 5, 2012 @ 5:24 am
Hi,
I did this last night. It DOES work, but not perfectly. I have this connected to a mid-2011 iMac. I’m only getting .7 volts DC between red lead and ground instead of the 2.8 VDC that this device wants to see. Is this a compatibility issue with the iMac vs the handheld devices?
Thanks,
Michael
John
April 5, 2012 @ 5:08 pm
I believe the iMac only has line in, no powered mic in. This was certainly the case when I tested on a 2011 Mac Book Pro.
So unfortunately, I don’t think you’ll have good success with this cable and the iMac.
John
abteenz
July 31, 2012 @ 11:26 am
can you teach how to build the one that connects to the usb port of ipad?
John
July 31, 2012 @ 11:32 am
Making an interface for the 30-pin dock is a much more complicated effort, and would require becoming a licensed apple MFi developer. I don’t think it would be worth the effort unless you were planning to seriously get into iOS dock-accessory development.
abteenz
July 31, 2012 @ 1:41 pm
thanks for your information.
another question do you know what is ettus research USRP n210 and what it does to an ios device?
John
July 31, 2012 @ 2:09 pm
Looks like a development platform with a Xilinx FPGA, for development of things like mobile phones, special radios, etc. See their website for more info.
Not something you’d use directly with an iOS device.
fotopdo
September 4, 2012 @ 11:51 am
Thanks for this video… just pulling parts together and seeing what I’ll need to purchase. One use I had in mind for this was as a virtual pedal board. I’m assuming that I can add a stereo 1/8″ to Mono 1/4″ jack to the headphone jack, and connect to my amp’s send/receive loop. Any problem with that?
El Guetari
October 1, 2012 @ 5:42 am
Hi have not found the 470 pf
can i replace with an other
thanks
Brad
December 27, 2012 @ 7:35 pm
Tried it using a headphone with built in mic. For some reason the two rings kept shorting out… tried everything I could think of. Will try again with better cable if I can find one…
Anjang
January 14, 2013 @ 12:32 am
hi john… u are great… anyway i just asking bout using your schematic to garage band…. is it ok ? cause i never try it… i dont have garage band yet…
Thanks john
John
January 14, 2013 @ 12:06 pm
Yes, it works fine in garage band.
John
Anjang
January 14, 2013 @ 12:43 am
another question john…. i have 3 option similar schematic, but i dont wich one better… cause im not a guitarist,
Another schematic:
http://sgitornado.altervista.org/diyirig.html
another schematic:
http://www.diystompboxes.com/smfforum/index.php?topic=85913.60
Big Thanks john
John
January 14, 2013 @ 12:09 pm
I obviously like the simplicity and size of my circuit. There’s nothing wrong with those schematics you linked – they just have more filtering, etc.
John
Brad
January 14, 2013 @ 12:09 pm
Built one using an enclosure to get the common ground I needed. Couldn’t find a 4 conductor cable with individual ground wires… I guess that would have been an 8 conductor cable. Problem I couldn’t out-think was how to get a ground to each of the split runs.
Also, have you tried this with an electric uke? I’m assuming it would be the same circuit?
http://www.amazon.com/Stagg-EUK-L-BK-Electric-Ukulele/dp/B005LD293C/ref=pd_sxp_grid_pt_1_0
John
January 18, 2013 @ 4:45 pm
My 4-conductor wire had a shield around each wire, available to be used as ground. They’re all electrically continuous to the plug shield. I demonstrate this is in my video starting at 3:10: http://www.youtube.com/watch?v=p1T8QmQowVQ#t=3m10s
If you’re asking if you can plug an electric Uke into an iDevice using this circuit, then I think it should work just like any other electric guitar.
-John
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Roger Lewis
April 7, 2013 @ 10:18 pm
Hi John,
Thanks for all the great videos they have been very helpful to me and the links in your excellent blog are also priceless.
I am working on my own Pick up modelling pedal at the moment and this is as far as I have got.
http://www.youtube.com/watch?v=Trb3UAXWNn8
A couple of more weeks should get me somewhere near finished I think.
Thanks again
Roger
John
April 10, 2013 @ 4:17 pm
Hi Roger,
Interesting project! I’ve never worked with Arduino, but it’s been on my to-do list for some time. Such an inspiring platform.
-John
Roger G Lewis
April 10, 2013 @ 10:45 pm
http://techwatch.keeward.com/geeks-and-nerds/arduino-vs-raspberry-pi-vs-cubieboard-vs-gooseberry-vs-apc-rock-vs-olinuxino-vs-hackberry-a10/
Hi John,
The Arduino is great and a fantastic learning tool. The creators of Raspberry Pi introduced it to get people back into programming as it was back in my School days ( Late 70’s)it was the PI that turned me on to Arduino and together they become the dynamic duo and peace will return to Gothem City.
In seriousness the Arduino, Pi, Beagle, Micro controller Community has really energised my own studies and the direction of my own creativity, coupled with Pure Data and also the Linux Audio project the vista of opportunities is both broad daunting yet very beautiful.
Its an exhilarating learning curve and your videos communicate the satisfaction and self affirmation that can be gleaned with some effort and not a little time. The results when applied to ones other hobbies though, are hugely rewarding.
In the initial link a new board called the Cubino is referenced and compared to the choices available in developer board world. I do like the look of that for my planned Rakarrack pedal which I am dubbing the ´´Daw on the floor´´. For now I am almost ready to assemble the final PD pickup replacer USB pedal controller, The Arduino whilst it can reference arrays is not in possesion of the horsepower required for real tine convolution Running Rakarracks convolvetron plugin under Linux on a Raspberry Pi Beagle or Cubino is where I am headed though, I have some LED displays I bought yesterday and will incorporate them into the Arduino shield. The pickup shield for the usb controller should be adaptable, for interfacing with the Cubino instead of the I Mac in my case. The Linux partition of my Mac is itching and all ready for the Rakarrack Daw on the Floor Project which I have been reading up on, probably unwisely, as I have been pursuing the other project.
Excuse the Rambling I guess you realise the similarities between the Loneliness of the long distance runner and the existence of the Woodshed hacker, reference the unwise multithreaded study beware approaching multiple lonely furrows metaphor,
Best wishes and thank you for taking the time to respond to my comment.
Roger
John
April 11, 2013 @ 3:15 pm
Inspiring stuff indeed! Good luck with your AdC/DaC and Rakarrack projects.
-John
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[…] interface connects to the 30-pin dock, which as I described in my DIY iOS interface project, is the higher-fidelity lower-noise way to get audio into your iPhone/iPad. This is because there […]
paul
November 16, 2013 @ 9:07 pm
Well, after many months of use with this, I decided to I would try to plug it into my MacBook Pro with the combination audio jack. It doesn’t work, much to my annoyance. The Sound control panel never switches to see the plugged in device as a microphone. I can plug in a set of earbuds that have a mic and it sees that as a mic. But not with the Zrig or DIYrig that’s documented here.
Is there a fix or workaround?
John
November 19, 2013 @ 2:29 pm
It may not be a powered mic-input. Check for a voltage between third ring and sleeve with a multimeter. If you’re not getting a voltage, then it can’t power the FET.
-John
nuno1959
December 22, 2013 @ 5:44 am
manufacturers must LOVE you !! 😉
thanks for posting
James
January 26, 2014 @ 1:43 pm
I am trying this project now. I’m using your video as a guide. It would be awesome to see some closer photos of the setup!
John
January 27, 2014 @ 7:34 am
Did you watch all 3 parts of the video? I showed extreme close ups in the breadboard test, and in the assembly.
Good luck with the project!
John
Giuseppe
March 13, 2014 @ 10:28 am
Hi John,
I need to change something if replace the MPF102 with 2N3819?
Thanks
John
March 13, 2014 @ 12:05 pm
I’m not familiar with that part. Take a look at the datasheets. You may need to experiment with resistor values, especially R2.
-John
Gustavo Varela
April 7, 2014 @ 10:55 am
John ! works on Macbook Pro?
Jewel
July 23, 2014 @ 7:15 am
Hey Man !
Im planning to do this on Android.
Ilove your concept that more like an irig type
awesome vids.
keep it up helping us newbies.
tnx alot
John
July 23, 2014 @ 10:08 am
Cool- enjoy the project!
-John
Jewel
July 25, 2014 @ 7:08 am
Is there any multitrack recorder for android ?
Tnx in advance IDOL 🙂
John
July 25, 2014 @ 8:32 am
I haven’t used any but a quick search turned up quite a few choices:
http://appcrawlr.com/android-apps/best-apps-multi-track
-John
Jewel
August 14, 2014 @ 8:08 am
Hey Idol John 🙂
If your DIY iRig Type Device works at guitars, Will it work on a mic ?
I think its just disame theory ?
Tnx in Advance Idol John
GodBless :))
John
August 17, 2014 @ 5:49 am
No, the circuit is designed to be high impedance for a guitar. Microphones require lower impedance, and higher gain.
John
Jewel
August 19, 2014 @ 7:19 am
So,what kind of circuitry am i going to do if im building a mic pre-amp ?
As always, Idol John thanks for the replies 😀
You saved me time and efforts 🙂
More Power for your blog..
It is really hard to make this things for woman hahah XD
Jewel
August 21, 2014 @ 3:28 am
Or Such a iRig PRE-Like Circuitry?
Is this Possible Mr.John ?
Tnx 😀
Ricardo Sanchez
August 12, 2014 @ 1:25 pm
Hi john i made the iDevice, but my ipad 3 don’t detect a headset input only
like headphones, so i can listen but it don’t detect a mic, and is the same
with or without the jfet. Only detect the ordinary handsfree. Can you help
me?
Mark
August 15, 2014 @ 7:54 pm
I also have this problem, but I got it to work a few times, but mine’s erratic, sometimes it detects the mic input, sometimes it doesn’t. 🙁
Mark
August 17, 2014 @ 4:46 pm
Fixed it, it seems that one of the ground wires got cut off.lol
Mark
August 15, 2014 @ 7:50 pm
Hi John, I made the device and got it to work the first time, but sometimes Amplitube can detect it and prompts the speaker/headphone output but sometimes it can’t detect the guitar’s input, the only thing works is the built in mic of my iPod Touch. Can you please shed a light on this matter? TIA
John
August 17, 2014 @ 5:12 am
I would guess that you have an intermittent short- an easy problem to have when everything is crammed into a tight space. You could try some pieces of heat shrink or electrical tape between your components. Another possibility is a bad solder joint- you could reflow each solder joint.
John
Mark
August 17, 2014 @ 4:47 pm
Thanks John!
Charlie Angel
August 19, 2014 @ 3:44 pm
will this work for an android phone ? they also have that kind of input.
zych faye
August 24, 2014 @ 12:32 am
Hello john i have a little problem when i connect headset theres no
sound,but when i remove 1of them it has sounds either 1 of them i put the
sounds ok but together thers no no sounds
Michon de villiers
October 19, 2014 @ 1:10 am
Great video, thank you very much.
Clyde Andrews
February 19, 2015 @ 12:47 pm
Thank you. you made it look so easy
Binu John
March 8, 2015 @ 6:49 am
MrBolinet
April 4, 2015 @ 3:01 pm
What is the latency?
Jermey
July 10, 2017 @ 10:22 pm
Can you provide info/schematics for this with android device
John Cooper
July 11, 2017 @ 12:14 pm
I haven’t tried on an Android device, but assuming the mic jack provides the necessary voltage, the same design/schematic should work fine.
-John
Ben
July 11, 2017 @ 11:48 am
Hey thanks for this! I built it and it works perfect!
John Cooper
July 11, 2017 @ 12:14 pm
Great to hear! Enjoy.
-John
dazz
October 22, 2017 @ 1:50 am
I’m gonna try this with my laptop, which outputs 3.8V in the 3.5mm jack mic. Will the difference in 1V output require a different R2 resistor? I understand I’ll need to fine tune it myself, so I’m getting a 2K variable resistor to get it just right in the breadboard before I build the circuit, just asking in case the increased voltage can cause other issues.
Thanks for the great work, John
John Cooper
October 22, 2017 @ 1:11 pm
Hey Dazz- sounds like you’ve got the right approach. I doubt that extra voltage will cause issues, but there’s only one way to find out! 🙂 Good luck with the project!
-John
dazz
October 22, 2017 @ 2:03 pm
Thank you John. So I take it I don’t have to worry about damaging anything if I set R2 too high or too low, right? At worst I’ll have the JFET either cut most of the signal or clip it?
John Cooper
October 24, 2017 @ 12:19 pm
Sorry, I don’t recall the specs- check the data sheet. Worst thing that can happen is a blown FET, so get a couple of those when you buy your parts 🙂
dazz
October 24, 2017 @ 12:24 pm
Understood, thanks once again!
dazz
November 11, 2017 @ 6:57 am
Just finished building this into an old guitar cable. Man oh man, it’s awesome! Having so much fun with it and my ghetto setup of 2nd hand guitar & laptop + Linux and Guitarix. Perfect if you’re flat broke like me LOL.
Thanks again John
John Cooper
November 12, 2017 @ 7:43 am
Cool! Nice work Dazz.
-John