Grundig WK

Converted to a Bluetooth receiver with a class-D amplifier. The radio is cleaned and where neccessary restored. The internals are removed and replaced by a Bluetooth 5.0 and a Texas Instruments based amplifier and a stabilized power-rail for the needed voltages is installed. All this is mounted on semi-hard foam in order to cope with British and Belgium road conditions. For the same reason everything that is screwed or bolted is secured with Loctite. Various filtering measures are taken in the power rail. Basically over-engineered, but different cars might have different effects on noise generation. For safety reasons everything is done to keep the thermal effects of the amplifier chip within limits and a 10 amp fuse lead is installed with an easy IP68 connector. For the same convenience 4 speaker binding posts are fixed. Either at the back or the side(s), depending upon your wishes.
Only the on-off switch and light stays functional.
Specifications
Power output: 2 x 25 watts at 4Ω
Frequncy response: 2 x 25 watts at 4Ω
Signal to Noise Ratio: 102dB
crosstalk: -100dB
THD at half power: 0.1%
Bluetooth: 5.0