Bluetooth and 3.5 stereo

[pf1junior]

I am working on a stereo build and I've always either chosen to go totally bluetooth or just with 3.5 stereo input. How can have a stereo with both? Do I need to use a switch or is there another way.
The bluetooth board is from Sure Electronics. And for this project I'm using very simple low powered amps for small speakers, similar to http://www.parts-express.com/2x2w-at...board--320-306.

This might be a simple questions, but I just didn't wanted to get started off on the wrong foot and order excess or wrong parts.

Thanks.

[tyger23]

Re: Bluetooth and 3.5 stereo

Basically, if I understand what you're wanting to do correctly, you'll need a 3.5mm jack that has a "signal pass-through" type switch. Something like this one:

http://www.digikey.com/product-detai...3545-ND/738702

Now, if you open the schematics for that jack, located on page 2 of this link:
http://www.cui.com/product/resource/sj1-354x.pdf

What you need to do is route the left and right signals out of the bluetooth receiver to pins 4 and 5 of the jack. Pin 4 is for the left signal and pin 5 is for the right. Then you connect pins 2 and 3 of the jack to the input of your speaker amplifier. Pin 2 is for the left and pin 3 is for the right. Pin 1 is for ground, and ground is common for the amp and the bluetooth receiver.

The way this jack works - the output from the bluetooth receiver will go into the jack and pass through to the amplifier whenever nothing is plugged in. However, when you plug something into the 3.5mm jack, then the bluetooth receiver gets switched out and the plug takes priority.

I hope this helps.

[Gordy]

Re: Bluetooth and 3.5 stereo

The will depend on the bluetooth module you decide to use. I recommend the Sure 4.0 BT module PE Part # 320-351. This unit has a line driver as well and will really push that 2x2w Sure amp. I do know that the Sure 2x8w amp has two types of inputs and they can both be utilized, so one for BT and one for line in. You just have to make sure that both sources are not playing at the same time.

This thread goes into detail your questions. Check is out and if you have any further questions just let us know.

http://techtalk.parts-express.com/sh...promise+keeper

[pf1junior]

Re: Bluetooth and 3.5 stereo

This simple solution is exactly what I'm looking for, Thank you for your help.

[pf1junior]

Re: Bluetooth and 3.5 stereo

I have one of those amps and had never tried to use both inputs before. I'll give it a try. Thank you.

[arrayed]

Re: Bluetooth and 3.5 stereo

I have just used a switch that allows you to switch from bluetooth or 3.5. This completely separates the two signals 100%. Also, you can rig the bluetooth 'power' thru the switch if it has enough poles, and this means the bluetooth will beswitched 'on' only when it is switched on. Most little bt modules, when they are first activated, make themselves discoverable, which is nice too... because then it is always 'ready' when you flip the switch and request it, connecting the audio at the same time. Just a thought. Search the techtalk forum for 'add bluetooth to anything' post. It is a day or so old, but there is a pic in there of how to wire stuff together.

also, the simple method of using the Sure bt board is apparently a great option. There is some issue with the output, which I don't totally understand, related to that board. But anyway, it is apparently a very good option as well!

[Gordy]

Re: Bluetooth and 3.5 stereo

I have one of those amps and had never tried to use both inputs before. I'll give it a try. Thank you.

I did a stacked config with the 2x8w amp this last weekend. It kept the footprint to a minimal, made wiring power very easy. In the pic below it shows a custom 3.5mm shorty cable. I ditched that for an RCA to cable and it just makes more sense.

You can see the amp on the bottom with leads soldered to the board. Those are the 3.5mm input that comes from the plug on the outside of the box. There is a plate that connects power and signal via the custom molex.