Turn A Cheap Bluetooth Speaker Into An Audio Receiver

Cheap Bluetooth speakers come in all different kinds of shapes and colors, and they let you conveniently stream music, for example from your mobile phone. For [mcmchris], they had one significant shortcoming though: while most of them come with some auxiliary input port as alternative audio source, they usually lack an audio output port that would let him route the audio to his more enjoyable big-speaker sound setup. Lucky for him, it’s a problem that can be fixed with a wire cutter and soldering iron, and so he simply turned his cheap speaker into a Bluetooth audio receiver.

After opening the speaker, [mcmchris] discovered a regular F-6188 Bluetooth audio module built around the BK8000L chip, with the audio jack connected to the chip’s aux input pins. Taking a close look at the PCB, the solution seemed obvious: cut the connection to the chip’s aux input pins, and connect the audio jack parallel to the audio signal itself. After some trial and error, the output pins of the on-board op amplifier seemed to provide the best audio signal for his shiny new output jack. You can see more details about the speaker’s inner life and a demonstration in the video after the break — in Spanish.

If the concept looks familiar to you, we’ve indeed seen a very similar approach to equip a Google Home Mini with an audio output jack before. The alternative is of course to just build a decent sized Bluetooth speaker yourself.

14 thoughts on “Turn A Cheap Bluetooth Speaker Into An Audio Receiver

  1. You can get a tiny dongle that does bluetooth to audio jack for 3$ if anyone is considering this but doesn’t have a speaker to repurpose. China is really into these bluetooth audio modules, you can get dozens of types some with amplification, some very simple etc.

    1. Yeah, those are pretty usable in car stereos which have Aux input, but no Bluetooth module. They also usually support phonecalls so you can talk in car without holding phone.

    2. Yup, that’s exactly what I was going to suggest. It’ll do a better job than this, too, since it’s intended for line-out, intended for the exact purpose this speaker was hacked for. They’re stereo, good quality, and contain a little battery for portable use, though you can keep them on charge full-time if it’s an application like plugging into a stereo. I set my mate’s stereo up like that last year, he loves it. Lots of people keep their record collection on their phone, if it’s not on their computer.

      There’s not much reason for this hack when the alternative is incredibly cheap and good, surprised the article didn’t at least mention the dongles.

  2. I didn’t comprehend this build at first since I’d think you’d just hook up the phone to the stereo directly via Bluetooth or even the audio cable… then I realized… oh yeah… home stereos don’t have Bluetooth where most cars do now and who wants to have to plug in a cable. Neat idea and great detail. I was looking at doing something like this at one time for making an amplified speaker telephone. Wound up finding an amplified phone for my Mom though.

  3. I did something similar with an insignia pico projector I have that has the bad combo of hdmi input, crappy onboard speaker and no way to physically output audio to connect with better sounding speakers. I ended up finding a tiny spot where I could just barely cram in a 3.5mm headphone jack I salvaged from something, and utilized the jack insert switch to detect an aux plugged in to cut off the onboard speakers and output audio. Works great and now I can plug in external speakers or even headphones.

  4. Blackberry had a Bluetooth audio receiver that works with any phone, Palm PDA, etc with Bluetooth and the ability to transmit audio over it. Plug in USB power and a 3.5mm jack.

    I could hack that into my 2007 Expedition EL’s line in to give it Bluetooth audio input.

  5. I bought one of the BT modules with the “50W” amplifier on it. I think it was under $10 including a nice laser cut acrylic case. I power it up with the power supply from an old IBM laptop, and drive an old pair of stereo speakers with it. It rocks. I was surprised at how good it sounds in fact. The only thing I don’t like it they soldered on switches for the functions instead of a berg strip. That surprises me as they could sell the switch bundles for a few more bucks.

    One thing to consider when you re-purpose a Bluetooth speaker is that some of them have eq on them that is tuned for the driver speaker that they came with. If you look into changing the device name of one of the BT devices you will probably read about the EQ options as well.

  6. If the manufacturer has done it right, than the internal chip equalizer is used to get the best sound of that speaker. Using it as a bluetooth receiver will give you the equalized sound which might not fell that good with other speakers.

  7. Hey, first thanks to Sven Gregori for sharing my content, i really apreciate that. And thanks to all of you that commented your thoughts. First of all, yes i know that there are dongles out there that works perfectly, but i just wanted to create something fast and cheap with something that i already had, an other reason is that i will use the hacked speaker to my room automation system and upload a new video showing how it works. If you want go and check my channel on youtube (mcmchris)

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