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Saturday, 14 December 2013

MP3 / iPod Headphone Amplifier TDA2822M Stripboard Veroboard Layout


The TDA2822M IC is a stereo power amplifier that I often come across in old walkmans/radios so I thought I would make a stripboard project for you people. Because I'm sure if you're an avid junk collector like me you will probably have one of these however if you don't; no worries you can buy them really cheaply from the grey market (or probably on digikey or something) below is a link to a grey market china shop I use often and so have had no trouble with. you could buy 50 of them for £3.56 ! so if you have 50 friends who have iPods that can't power headphones properly because they have piss weak amplifiers in them - since that idiot sued them - you can make 50 headphone amplifiers and sell them to your mates or whatever. Grey Market ICS

Anyway using this kind of IC is much better than using that well known CMOY amp design that is essentially more of a line buffer (which is useful in itself) but doesn't give you any extra power - where as this does!

The other cool thing about this IC is that you can run it from as low as 1.8 volts.

I know I will get questions asking me about its performance using different headphones so I am going to preemptively post the typical output power from the datasheet.

if you're new to reading datasheets this may look abit like gibberish but I'll give you a quick description of what you're looking at.
this is the part of the datasheet that deals with "Po" or power output and this is measured in watts (or in this case miliwatts
and they get these results from using a 1 KHz sinewave which is a typical test condition for testing a lot of electronic components (as listed under the Parameter section)
They then list the "Test Conditions" which in this case uses Rᴸ (Resistive Load - which in this case is a pair of headphones)
the other number "Vs" - is "Voltage Supply" (which I'm sure you know is whatever voltage you're powering it with)

Then we get to the Min./Max section - this is basically the Power Output of the IC (in miliwatts) using some basic test conditions.

So.. using this table I can get an idea of the Power Output with the headphones I own.
for example I have a pair of headphones on the desk here (for abuse)
using my meter on the resistance range I know that their impedance is aboutand I am powering the stripboard (below) using 2 AA batteries which should be 3 volts.
using the table above I know that the Power Output will be about 110mW - which is very dam loud when we're talking headphones. (there will obviously be some discrepancy because music isn't just a 1KHz sinewave but it's good enough to gauge how much Power we're going to get out of this thing.

Hopefully that is clear enough to understand (I know I'm not the best at grammar etc. - my brain is often all over the place)
but I urge you to take a look through the whole datasheet because it's very interesting (most datasheets are) HERE

Anyway - when you turn this on don't have your headphones on/in your ears in case you've made a mistake or your MP3 player is playing too loud. Use this amplifier at your own risk





11 comments:

  1. Hi Paul,
    How can i add a volume pot on this one ?

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    Replies
    1. Replace R3 and R4 with dual 10k pot.

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    2. Thank you,i'll try it !

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  2. This comment has been removed by a blog administrator.

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  3. Hi Paul,
    Can I bother you a little?
    Can I power two devices? from the same power connection?
    I'm thinking of using a USB conector to power the Amplifier (5V).
    Probably I will just need one time the C7, R5 and the led, correct?

    Greetings from Brazil.
    Paulo

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    Replies
    1. yes, that will be fine but you will need 2 of C7 or you might lose bass response

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    2. Thanks Paul, I can't lose bass response, because I'm a bass player, so I think you understand what frequency I like most (but not that ultraONLYbassfrequencylistenedinrapmusicbadlyexecuted).
      I would evenly ask to you how to increase the bass response, but since that I would make more questions and that will flood your comment area.
      But since you have answered my question maybe I'll enter in contact with you later, no more peace for you, MUAHUAHUAHUAHUA.

      Thankfully,
      Paulo

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    3. it's better if you ask questions via the comments section so that if other people have similar questions they can see the answer.

      this headphone amp will give you a louder version of the audio you put in. there's nothing in the way of a simple addition to give you more bass than is already on what you're listening to. I do plan to make a small HIFI EQ one day but it is quite a difficult thing to design.
      the TDA2822 IC is what they used to use in computer CD Drives back when they had headphone sockets on them

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    4. Hi again Paul,,

      I understand your point, but I'm learning eletronics form the beggining.
      I never built any circuit, so i have many doubts. There's a lot for me to learn.
      I would ask you questions that sometimes is not concerned if the circuit in question.
      So, what kind of capacitor i should use for 100nf?
      I have read that ceramic and polyester aren't suited for audio applications, but sometimes i see some people using them if no concern in audio.
      What are you thoughts about that?
      I will do what questions i can here, but will in the future try to stay focused on the circuit presented.
      When I learn more about eletronics, i think i will have questions for your others posts too.

      Thankfully,
      Paulo

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    5. don't worry, everyone had to begin somewhere - no one here is going to think anything bad of any question you ask.
      when I was very young, I asked someone a very obvious question to someone who has worked with electronics for years
      and they made fun of me for it - I called them a dickhead and vowed never to do the same if I was asked anything by
      someone starting out.

      as for capacitors - people say lots of things about them sounding "good" or "bad" but in reality it doesn't matter unless you are building extremely high power amplifiers
      where microphonic noise will be very loud so just use whatever type of capacitor you can get hold of and try not to be concerned about what audiophiles say because
      that time will be better put to use learning real electronics :)

      I meant that you ask questions in the comments thread of whichever project you're working on

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  4. Hi Paul, when adding a volume pot as you describe above, can you describe where the actual connections go to from the pot to the vero board? I am somewhat confused as to which wire is connected to the pot/vero.

    regards,
    Greg

    ReplyDelete