Headphone Amp (Chu Moy)

I Wanted to make one of these for a while now, not because my mp3 player lacked the power to drive my ashamedly poor headphone or that my headphones had a high impedance but because... it looks good and well, maybe in the future i may buy some good headphones and when that day comes. I shall be ready.

I also loved the look of the penguin mints Bought from Thinkgeek, this only aided my decision to make this amp.
So when i decided it was time to stop dreaming and start injuring myself with the soldering iron, i checked instructables first and was amazed to see no one had posted an instructable for this immensely popular diy amp. So i set about making my own, and this is how it went...

Note: for high res images layout images please visit my photobucket, as they are compressed here.
http://s149.photobucket.com/albums/s56/cew27_2007/Cmoy/

Step 1 Tools

The tools you need for this build are nothing special. All you need is:
A soldering iron
Some wire strippers (or in my case a leatherman squirt)
A multimeter

Pictured below my tools. The soldering station is an xytronics lf-2000 that i got about 3 weeks ago. any soldering iron will do, but i got this particular station because it was cheaper than the weller equivalents and parts are readily are available in the UK, and its performance amazes me. Highly recommend xytronics if you are after a good soldering station.

Comments

[JKPieGuy]

Hey I have a question. Is it possible to add 4 other ports so that 4 other people could plug their headphones into? Also can you have one of those volume switches to turn on the amp instead of a separate switch and have another switch as like a safety switch? (So that the volume can only go so high so that people don't accidentally bust their eardrums.)

[calligan]

Would using a 220uf 50v cap instead of the 35v increase the output volume and be safe to use? If not what would?

[flat_cat63]

You should be safe to use a cap with a higher volts rating so long as it's the same value. If available, you could get an L/C meter to test the actual value for best accuracy :)

[rohitkumarommi]

may i use another ic rather than opa2132pa please reply my id is [e-mail]

[jdubaya]

i noticed on the tangents site that there are way more parts. can i just get the parts from this page and still be fine?

[Cew27]

yes all the parts are interchangeable

[jdubaya]

okay thank you, they are out of stock on the DIP-8 IC sockets, gold contacts Digikey(AE7313) on digikey, does radioshack carry them or do you know anywhere else i can order them from?

[Cew27]

any component site will stock them, they are pretty standard.

[jdubaya]

okay. do you know of anywhere that might sell a kit with all of the required components? i dont want to go around store hopping

[Cew27]

Are you based in the uk? If so I can sell you a kit

[jdubaya]

sorry im in the us

[jdubaya]

where is the DIP-8 IC sockets, gold contacts? what are they, what do they do, and are they required?

[Cew27]

The socket for the op-amp is soldered onto the board as soldering the amp directly would damage it.

[rickycurrier]

Thanks so much for putting this up! I had issues on my amp I tried, and really alittle on the second, I couldn't get any right output. After my first complete failure I decided to order higher quality components but once it was built same thing bad sound in left and no right. I ended up taking the 10k pot out and that seemed to do it. I still have an issue when I move the amp but all I have to do is turn it off then back on and it works. Any ideas why? I checked all my joints and it looked good to me.

[novaforme]

Would this work with about 5 outputs for headphones?

[dr.tran]

Can i get a schematic of the circuit instead of the pictures of the components on the pc board? I'm planning on using a little bread board i have laying around that fits perfectly into an altoids tin.

[ph1lt3ch]

 Maybe there is a simple answer to this. I can only get audio to my headphones through the right channel, my left channel is totally dead. I have no bridges and i've done all i can do to figure it out. Thanks!!

[Cew27]

 hmmmmm, i had this problem with a unit i had, if there is no bridges (look reaaly close, could just be less than a hair width of solder) then i can only assume a component is faulty, but i never looked to far into what caused mine to behave like that, but it could the the op-amp or any capacitor or resistor that connects to the left channel. sorry i cant help any more

[ph1lt3ch]

 Thanks, I checked for bridges again, even ran a razor between all the contacts. So I think i'm just going to reorder the parts and have another go at it :D

Most likely its the op amp, i checked the capacitance of my caps so i'm sure i didn't cook one( which somehow i have done before-really really late night ). So the most expensive part is kaput.... And I even used a socket this time so no magic smoke hahaha. 

[Cew27]

ive got about 6 spare op-amps i got for free from texas instruments sat here, i never payed for mine. but if you get another and all the parts you need and it turns out to be something other than the op-amp, then you could probably make 2 with all the parts. 
good look, let us know how it goes! 

[ph1lt3ch]

Just ordered parts for a new one. Old one pissed me off so much it got shot out of my potato cannon to the tune of ~400 yards :D Made me feel so much better about the whole thing hahaha.

[fastcar123]

can i use this same thing to drive 4+ computer speakers to make a small portable guitar amp

[thesecret-96]

can i use the Dual Op Amp from radioshack (276-1715)?

[Brad I.]

Did you ever get an answer to this?  I would like to build this.  Thanks 

[shad0w88]

Thanks for tut.. I completed it in a few hours, that too on a stripboard!. Using your instructable and tangent's pages.

I hav one question though, if i find the increase in volume low, what can i do to increase in it?? I used a single 9V battery should I connect 2? Any other suggestions.

[Cew27]

you can increase the gain, im pretty sure i explain how to do this in the instructable somewhere but it has been a  while since  i made it i cant  remember.
glad it worked

[shad0w88]

 i'll check it out again.. best of all i made it for around $5, the amp was just <$3!

[knektek]

dude those are the same pics from make mag.

[Cew27]

no, i made these my self, they are the same circuit and so look similar

[KT Gadget]

 Do the capacitors have to be rated at 35V or can they be a different voltage as long as it is higher than the input voltage? Because I am getting the parts right now, but there are some radial caps that are cheaper from the 35V, which are 25V or 50V. The uF is the same, just the voltage is different. Will either of those 2 work?

I am making 2 of these, one for my self and another for a friend and I want to make sure i get the right parts.

[Jodex]

They will work fine.

[skolie]

 can i hook this up to a piezo to play the sound from that, and would this be able to power a small speaker for an ipod 
nice instructable :-)

[werb123]

nice mate, and this can make other stuff louder right?

i have a speaker that is 2" diamter, and the back part is like 1 1/2" it doesn't have anything on the back of it, and i was thinking about making this to make that run louder, i hooked up my bookbag to it, and it can fill a quit math room with music, :)

[caremusico]

nice job! a little question... i can do this (mono obviously) for making a boost pedal for electric guitar?. thanks in advance .

[ciderknight]

it's probably not powerful enough to be used as a preamp, but you can certainly try. not like it's expensive or anything. plus, if it doesn't work you can use it as a headphone amp.

[shams]

It is quite powerful bt u will need gain of 100 to use it with guitar....nd cmoy runs on gain of 1-15.......bt it is easy to make it 100 just change the resistor !

[Zem]

What would you change the resistor to for 100?

[shams]

It's not resistor it's the gain of amp.............higher gain means it will amplify more lower power signals to higher power signal......bt can suffer with distortion....so watch out !!!

[Zem]

 ... You said "bt it is easy to make it 100 just change the resistor !" what am I changing the resistor to??

[shams]

Gain=R4/R3+1.......this r two resistor in feed back loop.........