Speaker Cabinet Boom Box Build

When you get that itch to build something, it’s difficult to stop unless you achieve a feeling of accomplishment. And that’s how it was with [Rohit’s] boombox build.

He started out with a failing stereo. He figured he could build a replacement himself that played digital media but his attempts at mating microcontrollers and SD cards was thwarted. His backup plan was to hit DX for a cheap player and he was not disappointed. The faceplate he found has slots for USB and SD card, 7-segment displays for feedback, and both buttons and a remote for control. But this little player is meant to feed an amplifier. Why buy one when you can build one?

[Rohit] chose ST Micro’s little AMP called the TDA2030 in a Pentawatt package (this name for a zig-zag in-line package is new to us). We couldn’t find stocked chips from the usual suspects but there are distributors with singles in the $3.50-5 range. [Rohit] tried running it without a heat sink and it gets hot fast! If anyone has opinions on this choice of chip (or alternatives) we’d love to hear them.

But we digress. With an amp taken care of he moved onto sourcing speakers. A bit of repair work on an upright set got them working again. The bulky speaker box has more than enough room for the amp and front-end, both of which are pretty tiny. The result is a standalone music player that he can be proud of having hacked it together himself.

8 thoughts on “Speaker Cabinet Boom Box Build

  1. This nulls this effort but those play ports come with the latest digital stereo amplifier built in. Though the tuner couldn’t match a good car radio, if it does a local OK.
    Better to hack this model into a used car radio for it’s power amp and a real tuner.

  2. TDA2030 is said to typically draw 40mA of quiescent current. This times the supply voltage translates to idle power losses in the die. Even at the lowish 12V it is almost half a watt – it WILL get hot, not to mention at full output power the dissipation could get over 10W at 8 Ohm load. I would go for a Pentium II era heatsink.

  3. The 2030 is a very hi-fi amp compared to many of the other amp on a chip alternatives out there, many of which have 10% distortion at their rated outputs. I have built several kits using this amp from Chinese vendors, some cost under $10 shipping included and work well with torodial xformers salvaged from thrift store powered speakers that had aforementioned horrible chip amps in them. Yes, they do get hot and draw alot of current but if you listen to anything better than mp3 crap audio you will hear the difference in these amps lower distortion. Just put the part # in your favorite search engine and you will find a plethora of vendors selling kits, pcb’s, assembled boards and the chip itself.

  4. I recently saw the “boom box” post a day or so ago and scarfed up an old I-Home iPod cradle speaker cube from the Good-Will. The screen and buttons were dead so it made a fast candidate for a hack. The unit has a 10-12v wall wart supply so it is easily run off from batteries, and the bonus is that the amp is a TDA7266A so it was really easy to get up and running. It only took a little circuit board nibbling and some mating with old stereo volume controls in a old wooden wine crate with the I-Home 2″ speakers to get it going. Powering it off several reused laptop cells in a reworked battery set it all up for portability with a swanky leather strap handle from an old sewing machine cover.

  5. Nothing wrong with a TDA2030, but it is a linear amp. And like all linear amps, it will waste power and require a heatsink. If you want to lower power/heatsink requirements, try a Class D amp instead, which works much like a switching power regulator. Starting with a bare IC, they do require more external components than a typical IC-based linear amp, and so are a bit more challenging to build. Plus they operate at high frequencies, which may prevent successful testing on a solderless breadboard, and may require some attention to good layout on other types of boards (but not always, blind luck can often suffice). If you wish, both of these can be avoided by using a prebuilt module. Search Ebay for “class d amplifier module” in the “Business & Industrial” category and you’ll find a variety available at very reasonable prices.

    1. Class D amps can be lovely, but when they are bad they’re horrid. I have worked in the live sound field for many decades and I love the new pro Class D amps, light and cool compared to a rack of Crown DC-300’s but the cheap car stereo type amps have distortion spec’s that look nothing like a good ol’ linear amp. Instead of gradually distorting they hit a wall and go off the charts in a hurry, download some chip spec’s and compare. Also they are weird in the way thay respond to impedance in ways very different from linear amps so check the specs and reviews before you buy.

      1. Very true. Here is another data point for fellow readers. I have a 2x100W Class D amp. According to the specs it is 0.1% (or 0.01%, I don’t remember) THD up to 70W, from 70 to 100W it goes up to 10% THD. 10% THD is completely unacceptable so I consider it a 2x70W amp. Moral of the story, get way more amp than you need if you want it to sound nice at the levels you need. My 2×100 was about $40. got a 2×50 for like $15. They can be readily had all over the internet and can be usually powered by an old laptop power supply.

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