5W40

The main goal I need is to keep all original with limited mod but high quality stereo sound wireless through smartphone.

Here is my solution:

Smartphone or devices with bluetooth aptX profile support or at least A2DP
Bluetooth receiver with aptX support and HiFi DAC chip ($30 to $200, no huge different as I test)

First thing first is add on a aux input where I choice mod cassette as I never use it before.

Searching the forums, I got this apart from the center console













I need a power surply and a switch through cigar lighter receptacle


Disassembly a smartphone charger as bluetooth receiver power supply





Bluetooth receiver will hide behind panel





Option: you may not need a power switch if you wanna keep BT receiver ON all the time and that will keep mod more easy with constant power supper when ignition on.

Note: Aux input ground will connect with the metal frame behind panel.

You need mod a cassette adapter as it will running endless


I need slip sheets inside to eliminate friction noise


See the brown sheet



Seems nothing happened, now you can enjoy your Nakamichi high quality sound wirelessly.