Picture of Heinekamp
Hi, folks! In my first Instructable i will show you a guitar amp i've done using the stylish Heineken draught keg as enclosure and give you the directions to do the same with your choice of keg.

Sometimes you'll notice in the photos that something looks like it's been done before, some parts will be already soldered or cut. That's because this is kind of a staged instructable, since i had the amp done before starting the ible. I actually teared it apart and put it back toghether to show you fellas how to make yours.

That said, let us begin!

Step 1: Parts Needed

Picture of Parts Needed
To build the Heinekamp we'll need:

1x Heineken Mini-Keg (the small one, non returnable, 5L in capacity. other brands do it just as well, but don't forget the cool factor)
1x Amp circuitry
1x 120v to 9v transformer
1x Mains cable+plug
2x 3.5mm mono jack
2x 1/4" mono jack
1x Indicator LED, color to your taste
1x Toggle switch
1x 10k Log Pot
20x M5 x 25 Allen Screw
24x M5 Nut
8x M5 Washer
2x M3 Philips Head Screw
4x Rubber Bumper or any other shock absorbing bumper
4x Rubber band (the strongest you can get)
4x Speakers, various sizes, between 2 and 8 ohm, salvaged
Xx Metal mesh, enough to cover the speakers

- I'm using four speakers, in three different sizes. By using templates like i'll show, you can use as differente and as many speakers as you wish/your amp can drive/fit in the keg.

- The 2x M3 philips screw came from a random parts bin, and are used to hold the transformer. If you are using a transformer not identical to mine (needless to say, you are), look for the right screws to hold it down.

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Great tut!!!
Glad to see a different twist on the Little Gem...and, a MKII for a change.
One suggestion--and this is for the new folks. No need to add a tranny (transformer).
You can wire a simple dc jack into the circuit, and use a wall wart--they either have a tranny built in, while others are transformerless designs.
This will save you on some of the scrounging and certainly cut back several steps.

tulio_po1 year ago
Ficou muito legal mesmo.
Aqui, te mandei um e-mail mas não sei se vc recebeu o meu é tulio_po@hotmail.com
Martain2 years ago
Hey, this is an amazing design and I'd really like to base my college project on it (I've already shown it to my tutor and says it's ok as long as I can explain the maths) But I'm at an early point in my course and I'm confused at to where I would put the pots on the little gem mk2 circuit
boa cara!
vou fazer algo parecido.. to procurando ideias por aqui! mas a tua fiu da hora!

Que bom que você curtiu, cara! Mais de um ano que construí essa parada, já levei pra praia e tal e tá funcionando direitinho até hoje!

can i sit on it when its finished ? (serious question)
Gepetto Father (author)  curious youth3 years ago
Hmmmm... I never tried it. Let me see...

OK, I weight 65kg (not the heaviest guy in the world) and it stood well under my butts. Its just not comfortable - at all.

Ok then when i get my heinekeg (hopefully soon.) i shall post pictures of my heinekampseat LOL
Stunning, stunning, stunning, Gepetto!!

I love it....it has given me the idea to turn one into a PC tower.

Nice work!
Gepetto Father (author)  Kelticpaddler3 years ago
Thanks! (like, 7 months later =P)
icabod4 years ago

actually the mini kegs are made of steel, not aluminum. I've put speakers in a couple and I wish they were made of aluminum. Since they are steel, the magnets always fight with you when you install them!
dugthegreat4 years ago
where is your source of kegs?
Gepetto Father (author)  dugthegreat4 years ago
Hey, sorry for the misnaming of the kind of keg used. Thats a draughtkeg, or mini keg, and is pretty common in supermakets and convenience stores. Sells for about $20.
thanks for your reply
LiLGq4 years ago
Gepetto Father...i have a question...can you use a 9v battery for this amp???
LiLGq LiLGq4 years ago
another thing is...where did you place those 10k pot and indicator LED??
Gepetto Father (author)  LiLGq4 years ago
You do can use a 9 volt battery, but i have no clue about how long it would take for the battery to die. The circuit I used a 9V AC power input, that was then rectified by a diode bridge, but that would be easy to work around. The LittleGem amplifiers are based on 9V batteries, so if you build one, you would be using batts out of the box.
The 10k pot and indicator LED were originally on the salvaged amp circuit i use . The LED is soldered to the pcb and past through a hole on the faceplate. The pot I desoldered from the pcb, wired it to the pcb back again and then mounted through the pcb. You can see both LED and pot on the two first photos of step 6.

ANOTHER question again....about the little gem mkII amp....what is the actual type of capacitor used in C2 and C5/0.22 and 0.05 which of the two did you used??!!
mshaun4 years ago
Awesome instructable. Two questions. 1. how much was all the supplies it took to make this. 2. I've been looking for a speaker box or amp to hook to the line out jack of my work radio. I have the bosch powerbox and despite it's 4 speakers on top and subwoofer on bottom it is still hard to hear with all the ambient noise at work. Do you think your Heinekamp would work good for that. I know regular amps aren't although I don't quite understand the specifics of why. Again, awesome instructable.
Gepetto Father (author)  mshaun4 years ago
Thanks a lot! Glad you liked it. If you don't mind, please vote for the Heinekamp fot the Epilog Contest! Answers:

1. Let me see... The circuit, transformer, mains cable and the topmost speaker came from an old speaker set. The bottom ones from a broken cd player, the middle one from another cd player. The mini keg i had sitting around for two years (no kidding), waiting for some project to come up. The material for the control plate is from the leftovers-bin at schools metal workshop, so it was also free. Bumpers came from the same cd player of the bottom speakers. Rubber bands, small screws, zip ties and washers i already had.
I think I only had to buy the screws, nuts, metal screen and the toggle switch.
FINAL EXPENSE: ~ R$ 6,00 ( U$ 3,50). That much!

2. That's hard to tell. As I said somewhere here, I think the amp is definitely loud enough for a small party (it is limited by power and size, of course). I mean, it could to some point replace the sound system in my living room. Assuming that you don't work at a shooting range, i just guess it would work. Also, check your input signal strength. If it is too low you may need pre-amplification of something of the sorts.
Cool, Thinking of doing kinda the same thing but simpler. Basically I want to make a speaker box out of a pony keg. It's real loud where I work and I hadn't realized just how small the mini keg was when I first commented. Still, using any kind of a keg is a great idea especially considering I want it for work. Buy the way I voted for you bra. Keep up the good work and thanks.
Gepetto Father (author)  mshaun4 years ago
Nice, nice. For the sake of curisosity, what is your noisy job? (and thanks for the vote!)
I'm a welder. Shipbuilding to be precise. We work in a warehouse setting so you can imagine a few hundred people sounding off with sidegrinders, diegrinders, routers, etc...... It get's a little noisy. I pretty much have to be right on top of my radio with it all the way up to hear it. Which is sufficient but I'd prefer to be able to increase the volume a little bit.
Pentagrid4 years ago
Hya, I know I'm being a real wowser here but the mains (white) cord entry doesn't look that safe. I'm not sure what the wiring regs. are where you are but where I live (NZ), a knotted cord is illegal. It really needs to have a proper cable gland or similar to make it safe. As I said, sorry for posting a "downer"... this is an absolutely brilliant instructable:)
John Roberts.
New Zealand.
Gepetto Father (author)  Pentagrid4 years ago
Hey! That's no downer at all... chill, man! Well, I have absolutely no knowledge about any legislation over knotted cables, I've actually seen them in maaany off-the-shelf products I dismantled over time.

Guess things are more strict in New Zealand than in Brazil.

Anyways, it was nice that you to mentioned that. Recently I tightened and solidfied that knot with hot glue. It's brick solid now, and somewhat safer. The cord i used itself is low quality, so i will replace it in version 2.0 and a cable gland will surely be used.

Thanks for the compliments, and if you don't mind, please vote for this project for the Epilog Contest. Cheers!
AkKrock4 years ago
It would be nice if you add a circuit board for your amp too. =)
Gepetto Father (author)  AkKrock4 years ago
You mean the schematics for the board i used?
Yea, for your unready Little Gem Mk2.
Gepetto Father (author)  AkKrock4 years ago
Sure. The schematic is the last one on this page.


that's the official site of the little gems and variants. For the other projects involving sounds, check the "articles & schamatics" section at


Tons of interesting stuff.
incidentals4 years ago
The design is great..

I would have liked a flush finished bolt fitting like a coach bolt or a metal board mount that results in a number of spots rather than the large knurled allen bolt heads.

What about building an amp set in a couple of jerry cans all painted up like an prop from MASH

If you have a chance to look at the old bondai (imac) internal speakers snails you will see you dont need thet much room to make a nice sound.

Gepetto Father (author)  incidentals4 years ago
I have a penchant for allen screws, so i wanted them to stand out a bit more, but the coach bolt is not a bad idea at all. Imagine the keg studded with the bolts... would look great too.
I never watched MASH, and even had to google the jerrycans (i'm not a native english speaker, my bad!), but those are damn stylish, aren't they! Too bad they're very rare around here.
And I checked out the imac and the speakers on it were really small, as you said. I never had the chance to hear to that imac version, so i'll take your word.

Thanks for the compliments! I'd be very pleased if you could vote for this instructable for the Epilog Contest. Cheers!
I think you would get much more performance from your speakers, depending on their limits, if you did not use a little gem amp. Correct me if I am wrong, but the little gem amp does not even put out .5 Watts, and driving more than one speaker per IC will give you barely any volume, which means that this can only be used for computer speakers or other quiet indoor applications. If you want to give these speakers a bit more bang for just about the same money, you can use the tda2822 which is almost identical to the lm386, but it puts out about 2 Watts. If you really want to have some fun, you can try the tda7240 which can put out a max of 20 Watts, depending on how you set up your circuit. Great project.
Gepetto Father (author)  AaronLauzier954 years ago
Truth. I suggested using a LittleGem MkII, which uses two LM386 and pumps 2W. The initial idea was to have something to carry around easily, plug in a guitar and jam, eventually an ipod, so i wouldn't need it to be all those 20W loud. Fact is that i used a (i think) 1.6W el cheapo speaker set (bought in 2001) and it still sounds surprisingly loud. I do have some issues with vibrations when on max volume, but i look forward to damp some of the bass stuffing the keg with foam, and then i post the results. What i mean is that i just don't need it to make much more noise than it does now, suffice for the little parties it was intended for. And, hey, thanks for the compliment.
Sounds good, keep up the good work with the build. (I just like to be able to crank it up sometimes)
Lubaaas4 years ago
Nice project!
Too bad you used a Heineken Keg though, Heineken stinks :p
Gepetto Father (author)  Lubaaas4 years ago
Haha, thanks! C'mon, Heineken rocks =D~~
Not if you have great Belgian beers like Jupiler, Duvel etc at your disposal :D
rhoaste4 years ago
Although I respect your post, I see no consideration in cabinet design in relation to speaker characteristic. This alone is a good enough reason not to consider this build despite there being a multitude of other fundamental issues in design.
Gepetto Father (author)  rhoaste4 years ago
This project had as guide the idea of making a small speaker enclosure/amplifier system that was resistant to wear, handy to carry, decent in sound and, mainly, fun to use and show to your friends. I do know i don't adress basic issues in cabinet design (probably the only one was to choose the ported variant for its ease of build), but that's not the point. This is more of a test rig than a off-the-shelf professional cabinet, and for being so it sounds great. If you please, consider that I'm still working on this, trying to improve it, and that the instructables community and I would really appreciate some tips from people who have a better grasp of the subject, like yourself.
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