Introduction: Hack and Upgrade Your Stereo System With a Bluetooth Module

Picture of Hack and Upgrade Your Stereo System With a Bluetooth Module

I have this stereo amplifier that has a great sound but without wireless connectivity.

With a few bucks and a bit of patience it's possible to make it a great bluetooth stereo system!

Step 1: Buy Some Components

Picture of Buy Some Components

You will need:

  • A bluetooth module xs3868 (less than 4USD on eBay) (see picture)
  • A 3x7cm prototype PCB board (less than a dollar on eBay) (see picture)
  • A 470µF electrolytic capacitor
  • Some single row straight headers
  • Your iron and solder
  • Some wires

Step 2: Assemble the Components Together

Picture of Assemble the Components Together

Solder the headers on the PCB, then the Bluetooth module to the headers.

Solder the 470µF capacitor as described in the picture.

Solder 5 wires:

  • 2 wires for the power: red to +5V pin and black to ground pin
  • 3 wires for the output: white to ground pin (Agnd), blue to right pin (R) and green to left pin (L)

Step 3: Open Your Stereo Amplifier

Picture of Open Your Stereo Amplifier

Safety first: unplug your amplifier before doing anything.

Then unscrew the cover and try to locate any 5V voltage regulator like the one in the picture.

You will also need to locate where the RCA plugs are connected.

Step 4: Connect Your Circuit to the Amplifier

Picture of Connect Your Circuit to the Amplifier

Solder the output wires to the desired input RCA. Make sure you are soldering correctly (ground, left and right).

Solder the power wires to the voltage regulator.

Step 5: Test Put an Antenna and Cover

Picture of Test Put an Antenna and Cover

This is it!

You just have to plug you amplifier, be careful not to electrocute yourself!

With any bluetooth device (smart phone, computer, tablet etc.) try to connect to the bluetooth module and play some music.

You should hear some nice wireless sound!

If you don't unplug your amplifier and double check all your solders and connections.

Before covering you will need to add an extra antena soldered to the existing one because the cover will certainly block any electromagnetic wave to get out from the amplifier, and also to get inside your amplifier, including the bluetooth waves.

Drill a small hole and pass the wire/antenna through it.

You just need to cover your amplifier back and you're done!

Thanks for reading!

Comments

nishabe made it! (author)2017-06-10

I made this one week back for a slightly different use case.

Here is my experience:

https://www.instructables.com/id/DIY-Bluetooth-Headphone/

ClemRz (author)nishabe2017-08-16

Awesome!

steventurner84 made it! (author)2017-08-16

Had never attempted anything of this nature, as I am more of a mechanical guy but I needed Bluetooth and had a perfectly good receiver. Followed as best I could, but made a few changes (primarily due to inexperience). Had fun and learned a few things as well. Hard to beat that kind of night!

YashS121 (author)2017-02-26

Hello There

I want to make a bluetooth audio transmitter for me to connect my laptop with 3.5mm jack with my wireless headphones. How will I be able to do so using this module.

ClemRz (author)YashS1212017-02-27

Oh, ok, got it!
So in step 4, instead of connecting the wires to the RCA you have to connect them to a male jack plug. Also you will need power source, USB should be fine.

YashS121 (author)ClemRz2017-02-27

Ok, how would I connect both the device? Because both the device dont have a user interface.

ClemRz (author)YashS1212017-02-27

As usual, via bluetooth.

YashS121 (author)ClemRz2017-02-27

I mean how to pair them because I would be unable to look which device to connect etc. (Won't be like a device connection with phone). As on phone we get a list and then connection is made.

ClemRz (author)YashS1212017-02-27

Good point! No idea!

YashS121 (author)ClemRz2017-02-27

If I am correct tgen, connecting the wires to the male jack plug would still be doing the same thing as in your project, because you are connecting those wires to input of the amp. And if I do so then I would using it as an input of what tge device recieved. However I want the opposite, that input is given to the device and it transmits.

ClemRz (author)YashS1212017-02-27

Right, you are correct. AFAIK there is a mic input on this board, use this input for your jack.

ClemRz (author)YashS1212017-02-27

Hi, I don't understand what you need to perform. Do you want to put a wire on wireless headphones? O make a wired headphone become wireless?

YashS121 (author)ClemRz2017-02-27

Thank you for your reply, I want to give my laptop wireless capability because it lacks bluetooth. So what I want is that a bluetooth transmitter will be connected to the laptop, so I can listen to the audio on my bt headphones (streaming laptop audio to headphones).

YashS121 (author)YashS1212017-02-27

Nevermind, Didnt look at the second reply.

nebloid (author)2016-07-07

Should only be powered by 3.6-4.2V. Dont exceed the max voltage. I used 3.7V li-ion battery.
There are a few versions of this board and the documents available on-line are sketchy at best. Be sure you have the right one for your version. I have purchased a few of these boards and not one seller has been able to provide the relevant datasheet for their version.

jamesrb (author)2016-03-09

These instructions are missing some vital information. The circuit diagram does not have a "470µF capacitor" mentioned in the "you will need". The picture clearly shows a resistor not mentioned in the "you will need". The picture of the circuit board is too small to figure out the discrepancy. It would be great if someone who actually made this work posted these corrections.

tclayton (author)2015-12-22

The circuit is simple and this is a fantastic idea, me personally I've been building amps from scratch and have really wanted to add bluetooth to them , I have 2 of these bluetooth modules , my real issue here is how small it is , do you have any tips on soldering connections to the pins? This chip is so incredibly small! I already ruined one in attempting to solder wires to it

JasonM15 (author)2015-05-12

I have done a few Bose Sounddock mods over the last few years because the price of older bose 30 pin Sounddocks have been declining in price since the new apple gen 5 connector. I internally integrate hifi bluetooth modules into the Sounddock; I used Sure Electronics aptX modules from the sure hifi store. My favorte build is a Sounddock portable; It's 100% portable and sounds awesome.

The time saved by using the sure modules definitely offsets the higher price ($23.90).

I also worth while to add if you cant locate a suitable 5V power supply most of these HT amplifiers / recievers have a AC outlet on the back you can splice for wall power adapters.

Great instructable, Good design and execution!

- Jason

munecito (author)JasonM152015-11-07

Hello mate.

I have a question for you and I hope you can give me a hand.
I found a nice speaker set with auxiliary input and a 30pin ipod docking port on top which is pretty much useless to me.

You said that you have converted some Bose sounddocks to bluetooth by using th Sure Electronics aptX modules. Do you happen to have a wiring diagram for it?

As far as I can see in my speaker thing there are 5 cables going to the male docking port. I assume they are 5V+, GND, Audio Output L, Audio Output R and Audio Output common but I don't really have an idea of the 30pin docket wiring.

I am lucky that this thing is clear perspex and I can actually see it guts without having to open it.

Ideally I woud like to use somethhing like http://www.ebay.com/itm/Black-SD-FM-MP3-Player-Mo... to be able to use it also to recharge other devices via the USB port and maybe even play music from cards and USB drives as well as bluetooth but i guess I can settle for just bluetooth connectivity.

Thanks.

JasonM15 (author)munecito2015-11-07

Hi,

If you have soldering skills, You can solder your player into the 30 pin apple header:
- Pin 2 is audio ground
- Pin 3 is audio right (red)
- Pin 4 is audio left (white)
- Pin 19 and 20 need to have a 2K OHM resistor soldered between them (to simulate a docked iPod)

I also use the dock to power the Bluetooth module, Some docks can't be used for this beacuse the voltage levels aren't comptible with the bluetooth module:
- Pin 16 is power ground
- Pin 23 is Vcc
I would use a meter and see what voltage the dock uses, The Sure modules use linear regulators that work from 9V-15V DC.

Another option is to get a bluetooth 30 pin module from E-bay...

Lee Wilkerson (author)2015-05-12

A beautifully simple project. I would have connected the BT antenna through about a .01 Mfd. disc ceramic cap. (you will probably need to experiment with the capacitor value or calculate it for 75 ohm load) to the existing antenna input connector.

Lee,

I'm relatively new to Electronics, I got started about 3 months ago and I'm still learning. What is the purpose of a capacitor on the antenna? I'm not challenging it, just curious what purpose it serves. Thanks!

The capacitor electrically isolates the module from any stray DC that might be roaming around as well as isolating it from the RF preamp stage of the stereo..

Somebody might plug the "loose" wire to the speaker outputs, an outdoor antenna or the power socket, any one of which could fry it. If you put a very small value capacitor in series with the antenna lead, it will keep DC and low frequency AC out of the receiver. The value is not critical; anything in the tens of picofarads up to less than a microfarad ought to work. Just use a ceramic, not an electrolytic. I haven't found the schematic, but there's possibly one on the board already.

ClemRz (author)jimvandamme2015-05-30

Good idea! I will try that and update the instructable, thanks!

AniketB3 (author)2015-09-20

how is the audio quality with this wireless bluetooth setup? would the audio quality vary/improve if a different board setup/ different electronic components are used?

plabuschagne (author)2015-07-13

o ordered this bt module from dx.com for a bt speaker I want to make. cant find any data sheet for it. why dit you put resistors/capacitor in? and the 1.8v is it the ground for the play/skip/vol ect buttons? I didnt relise I needed extra components, or do you think I can leave all that out and cannect power and buttons directly? im using a 3.7v li ion cell and pam8403 amplifier board. gr8 way to incorporate bluetooth to a amp!!!

ClemRz (author)plabuschagne2015-08-24

Hi plabuschagne,
I first tried to put a LED as shown in the diagram but this wasn't working as expected, this is why there is a resistor. The capacitor seems to be needed though.
Thank you for your comment.

lutkeveld (author)2015-05-10

Don't think that module likes to be fed 5V right?

jimvandamme (author)lutkeveld2015-05-17

I'd feed it through a 3.3V regulator or just a resistive power divider.

DanielL32 (author)jimvandamme2015-08-24

It has an internal regulator for 3.3v and it will under voltage the rest of the circuit if you feed it 3.3V, it works however you will get terrible audio quality, at least in my tests. Seems like 5v would be ok but I can not confirm this I am using a lm317 regulator adjusted to 4V.

ClemRz (author)lutkeveld2015-05-30

I couldn't find a "nice" data sheet about this module. I've read that if it's powered under 5V it won't pair with devices... I will try with a power divider. Thanks!

dmarax (author)2015-05-12

I just ordered. How is the sound quality? It is powered by 5V?

RampRabbit (author)dmarax2015-05-31

its best powered by 3.6 to 4.2 volt

I bought it and works a treat

ClemRz (author)dmarax2015-05-30

It is powered with 5V DC but I couldn't find a reliable documentation on that. The sound is ok yet a bit noisy when no device is paired or transmitting.

LongJ (author)2015-05-25

Use an old WiFi antenna ..... WiFi and Bluetooth use the same frequencies and the antennas basically the same except the WiFi tend to be better and have more 'gain'. I like to take the WiFi antennas from an old laptop or tablet and use them because they have more gain than the stock Bluetooth ones do and that means more range and better signal quality and it's easy to find a place to put them. I added a similar module to the 'mechless' car stereo in my boat but since it is in a steel case it blocks the RF and worse yet picks up all the RF trash from the micro in the radio. But the front cover is plastic so I basically taped down a WiFi antenna from a junk tablet I had to the inside of the plastic cover and ran a piece of coax to the module and now I can stream music from my phone or my Android and Win8.1 tablets

ClemRz (author)LongJ2015-05-30

Nice idea! :)

grastuco (author)2015-05-14

I like this idea and would like to do the same. I am wondering though is this bluetooth module standard or budget model and would I be able to invest in a better quality one for better sound throughput? Given, say a $10 budget increase it would pay off to get the best sound possible.

ClemRz (author)grastuco2015-05-30

Hi, you would definitely have a better output sound with a greater budget!

rgunasekaran (author)2015-05-10

can I use an hc05 BT module instead of this one??

ClemRz (author)rgunasekaran2015-05-30

Hi, hc05 will be more difficult to use as this is not an audio dedicated module. However I'm sure you can find "how to"s on the Internet.

StevenDeDomenico (author)2015-05-24

Hi, would you be able to redraw a schematic to follow. The instructions are not that clear. Cheers.

jimvandamme (author)2015-05-17

Where can you get a transmitter module? I can get plenty of receivers, but I want to make a BT link for my guitar (among other things) and fit it in a 1/4" phone plug.

Justin3266 (author)jimvandamme2015-05-22

Bluetooth Transmitter and Receiver, Mpow® Streambot 2-In-1 Wire... http://www.amazon.com/dp/B00P20TFWM/ref=cm_sw_r_udp_awd_TO4xvb18M8390

Raphango (author)2015-05-21

Great and simple! =D

Ah-che (author)2015-05-15

I suggest to put something about this

http://www.globalsources.com/gsol/I/Bluetooth-antenna/p/sm/1002276471.htm#1002276471

for BT antenna :) for the perfect look and high range :))
Perfect little project - i will make it :)

sportq (author)2015-05-14

I did this to my Yamaha micro hifi. Instead of using the AUX input (which I thought I might use for TV audio) I used the Phono input. It's not as simple as there is some input biasing on the phono input. Both the AUX and the phono inputs were on a daughter card which was easy to remove so I de-soldered the last resistors in the input chain and fed the Bluetooth audio in. The phono inputs is now defunct but I can reinstate it easily in the event I want to play vinyl records.

I used the KRC-86B Bluetooth 4.0 module, also very cheap from eBay. Unfortunately the pin spacing is not 0.1" making it a bit more difficult to use.

stephen.small.92 (author)2015-05-13

How about a wifi to blutooth converter. and a wifi streamer in the amp. Need additional range?

Beetlesmart85 (author)2015-05-13

i usually use the Altium to do the design, but there are always some problems when generate gerber file. sometimes, the file is not complete. can you give me some advise?

by the way, after comparing some manufacturers, i found the china manufacturer's price is competitive, a worthy large production country. jaja. i had brought from pcbpool for one time, very good quality, but the price is expensive. my friend recommend to use: www.pcbway.com/j, a manufacturer from china, it's good, low price with good quality, i was amazing. and use this url, can get a $5 usd coupons, jaja, so good. hope it can help you.

script_coded (author)2015-05-10

Great! Tried this with a Bluetooth headset I had laying around once, but it turned out not to stream music, only calls :/
I'll defenetly try this!
Thank you for sharing your i'ble!

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