The Macamp - the Personal Sound Amplification Device





Introduction: The Macamp - the Personal Sound Amplification Device

About: I like to modify things, make things, and modify the things i make. im no math whiz or someone with perfect grammar, but i am good at making things. at my school ive taken the welding, machining, mechanics ...

In this instructable, I am going to show you how to make a personal amplifier from near scratch.
I put mine inside a macintosh 7200 casing because of it's size, and how easy it would be to work with.
1x pc motherboard
1x casing
1x power supply
1x cd-rom drive
unlimited lights
2x power switch
unlimited fans
2x dollar store "Spy Ears"
1x speaker

Grab your tools, and let's get started!

(sorry for the blurry photos, i have a bad camera)

Step 1: Find a Case and Gut It

I chose a powermac 7200 case, because it is a quite large case, and i already had one laying around.

You are going to need to completely empty the case, Be sure to remove everything, being careful to not break the plastic, it will most likely be very brittle from so many years of age.

Also remember to unplug everything, or you might run into trouble along the way.

Step 2: In With the New

Now that the case is empty, it's time to fill it again.
For this, you will need:

-An old motherboard
-A CD drive with volume control and a headphones jack
-A speaker
-A fan (optional,an nmb peewee boxer is perfect, or a thin one from a laptop cooling pad will work)
-A cheap microphone (for the plug)
-A floppy filler piece
-A soldering iron and solder (look at the cd drive's steps for more info)

The first thing to go in will be the CD drive. This takes a couple steps
1-Detach the mounting plate from the old cd drive, and attach it to the new one
2-Slide the CD drive into position, being careful about the plastic
!!~even if your cd drive has a play/skip button, you still need to do the following steps~!!
1-Open the cd drive
2-Locate where the play/skip button would normally be (usually by the eject button)
3-solder a long pair of wires to the area where the button's leads would go (make sure you get the right contacts, if you don't, it wont work)
4-Close the cd drive, making sure the wires come out the back

Next will be the motherboard. This too will take only a few steps
1-Find a good position for your motherboard, with a mounting hole over the mounting post
2-Attach the risers, and tape the floppy plate on the corner closest to the pci openings in the case. this is necessary, because if you don't, the motherboard could short on the metal tabs that are there
3-Mount the motherboard in place
4-Remove the heatsink and CPU, they aren't needed

Up next will be the speaker.
1-Cut the cord on the speaker and on the microphone.
2-Strip the two cables you just cut
3-Connect the two wires inside the cable to the speaker (if your speaker doesn't have wires attached, you will have to solder some on to it)

Now for the fan. It will be at the back, behind the power supply
~note it isn't necessary if you can get the original fan to fit in the power supply~
1-Carefully break out some of the plastic behind the fins at the back, big enough for your fan
2-After making sure the fan fits, use some fan screws to mount it in place
3-Attach wires to the ones from the fan, making sure they are long enough to get power

Step 3: Power

Now, to fuel the stuff you want to put in this, you will need one thing: POWER.
An ATX power supply will be put in the original macintosh's power supply casing.

you will have to find a way to hold it in there, i used washers and the original mounting posts in the case. you will also have to reconnect the fan you choose to use, and properly ground the plugs. The pictures will help explain in a little more detail.
I used a couple pieces from a dollar store mechano kit to help hold it in place

Step 4: Switches

In this step, I will show you how to install a regular pc power switch in the casing, and make the control panel that will turn the cd player on.

To install the power switch, you will first need to take the plastic button piece that originally pushed the power button inside the mac. cut off everything so it's just the end of the button.
Next, you will need to take some tape, (masking tape works fine) and make one or two passes around the outside of the switch so it fits snugly into the hole where the old button used to be. Add a ring of hot glue around it to hold it in place. now take a small metal nut ( I got one from a dollar store mechano kit) and twist it onto the end of the switch. hot glue the button piece you cut off earlier to the nut.

Now for the control panel. I took a plastic lid and traced the opening for the hard drive bay on it. Then I cut out the square, and got a digital digit screen. I traced a hole for that, the push switch, and the audio level for the cd drive amplifier. I used some more mechano to construct a frame to put on the back of the panel and keep it from deforming because of the switch. the cd player's amplifier (a spy ear) draws 12 volts of power from the digital display, which is hooked up to 12 volts. I had to test with the connections on the back of the display to find out what connections were power out. they were the last two for me. my display burnt out on me, because it wasn't designed for 12v. But it still let the amplifier draw power from it, so there was no need to worry. You could just directly attach the amp to the 12v, but I didn't because I wanted to use the display.
the audio level reader is just a battery level reader from an old tape player.

Step 5: Amplifiers

Now it's time to make this thing sing. I used 2 spy ear toys just like the ones in the picture, and removed the cases and microphones. where the microphones used to be attached you need to attach an audio jack. this is sound in. where the headphones jack is becomes sound out. after attaching a jack to one, find a way for it to get outside the machine. this will be for mp3 players, ds's, ipods, etc. plug the speaker into it. solder wires to  the positive and negative battery terminals. put the negative wire into the -5v part of the power plug. this wire is the one next to the red wire. do the same for +5v, except using the red wire instead. if you want, you could use 12v, but I used that for the cd player. do the same for the cd player's amp, and find a 90 degree plug to plug into the cd player, and attach to the amp. i just soldered a headphone plug instead. now get a jack and attach it to the built-in speaker. plug it into the cd player's amp. you now have created an amplifier. of course turn the volume to max on the amps, and just a little up on the cd player itself. for mp3 players, the volume can be at about 4/5 max, because they don't put out as high of a frequency sound.

Step 6: Lights

gather all the lights you want, because now you can go crazy! (if your power supply can handle it as much as you can)
Add cold cathode lights, leds... any lights you want. but remember, if the light doesn't have any resistors on it, you will have to add them, or else leds will burn. so, to save you the frustration, (and the smell) add resistors to every led you use.

Step 7: Double Check Everything and Turn It On

Double check every single connection inside your new unit, plug it in, take a deep breath, and press power. if nothing happens, think:
did you properly ground yourself by touching the metal case?
did you properly connect the power switch to the motherboard?
were you careful enough with the power supply?
try triple checking connection

if it did turn on...
plug that iPod in, and press play! (if it sounds distorted, turn down the ipod or mp3 player)
Put in that CD and press play! (again, if there is distortion, turn down the volume)



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    21 Discussions

    Why did you put a PC motherboard in there? It doesn't seem to be doing anything besides turning the power supply on. You could have just reused the original power supply and motherboard to do the same thing. That would eliminate the problem of trying to mount a motherboard and power supply that weren't designed to go in there.

    okay i think i figured part of it out - i just had the 1.5v battery in there. I hooked it up to a 9V, and it puts out a lot more sound, but it sounds like crap - totally distorted, no matter what combo of volume between the ipod and the spy ears.

    1 reply

    are you using the same speaker? try using one with a higher ohm count, you will probably get a better sound quality than with a speaker with a lower count

    it's not distorted at the combo you reccomend - all the way up on the amp, really low on the mp3. but it's quieter than a headphone.

    3 replies

    i said 3/4 on the mp3. loud, but not so loud you are overloading the amp and just getting fuzz

    anything over 1/10th loud is way distorted. I'm using an 1/8" plug connected to the mic leads with alligator clips.

    1: what mp3 player are you using?
    2: try turning down the amp, you may get better results.
    3: try putting a capacitor between audio out and the speaker. (4.7 or 47 uF should work)

    i hooked up a spy ear amp to a 3" 8ohm speaker and then used an mp3 player as an input into the spy ear mic - and it doesn't seem to me to put out alot of sound, in fact, it's pretty much like a headphone. What am I doing wrong?

    1 reply

    first of all, how much power do you have going into this? i have 12v in mine, so a 9v battery would work fine.
    second, did you connect a audio jack to the mics wires? or did you do it some other way?
    the smaller the speaker, the worse the sound is. the speaker is used was a 16 ohm one, and the sound is considerably loud.
    if none of this works, post back and ill see what else might be wrong.
    i read somewhere that you can remove the fuzz by adding a capacitor on the audio out line. im not sure how, but im sure there is an instructable somewhere here that'll help!

    good luck!

     This is awesome, in theory this should just be as easy with more up to date dells and other computers right?? I shall be looking at my home dead computer for surely! :)

    1 reply

    yep. i just chose the mac for its case and the motherboard that was in it didn't suit my needs. but yes, you could use newer computers, and make sure your power supply has a value of more than 250w, or else you will be having the trouble i am, with all the lights, it'll sometimes turn off

    speakers can be aquired from just about anywhere. the speakers from old pc's would work too. they're still speakers, right?

    Meh... unless you break them ;_;
    Well, I guess I shall continue my search.  Thanks greatly for the tip about the amplifier, I have one of those toys.

    and the best part is, they only cost about $1 to get! i wasreally surprised about how loud those things can get. i really hate the mic feedback though. but you know what? i put 12 vots through that thing and it still hasn't blown up yet!

    Hmmm.... idea! I could put two computer speakers in to a box with an Spy Ear to amp it up for portable use with my mp3 player! Would it work if battery powered? I think so... if not I will design a power budget.

    hey, its battery powered to start with, isn't it? and you could put a 9v battery in there and still do no harm. much easier than making the amp from a cd drive or from scratch. perhaps i should make an instructable...