Sunday, January 14, 2018

Bluetoothifying a Tivoli PAL FM Radio

Norway became the first country to shut down national broadcast radio on FM. We have now switched to Digital Audio Broadcasting (DAB) leaving a lot of FM-radios useless.

I have a few Tivoli PAL radios with fairly good sound quality. They are also rechargeable. To increase the usefulness of the PAL, I wanted to bluetoothify it. I bought a KRC-86B Bluetooth receiver on Ebay and mounted in inside the box.

Luckily, all the module need is +5V and GND, and it delivers stereo audio. Inside the PAL, the audio amplifier circuit and the FM circuit are on two separate boards. All I had to do was to rip out the wires going to the FM module and connect them to the Bluetooth module.

The FM module is the vertically mounted board, and the main board is the horizontal board with the mini-jack connectors. The connector on the main board (white wires) on the PAL has the following pin-out (left to right) Right audio, Left Audio, GND Audio, 5V, GND.

I mounted the bluetooth module on the back of the tuning capacitor. There is plenty of room inside the radio.

The verdict: It is easy to connect the radio to a smart phone. It shows up as KRC-86B v4.0. The sound quality is fairly good. However, there is some noise to be heard. As of yet, I have not figured out the cause of the noise or how to get rid of if.