Philips AD906WA Wireless receiver

Date: 2025-11-18

Tags: elec teardown audio

Overview

This AD906WA/01 wireless receiver came with a LX3950W/01 home theater system and was paired to an AD906WT/01 transmitter1.

Several wireless transmitters were offered for home theater systems, as a way to connect the rear speakers without long cables going across a room2.

The wireless transmitter was connected to a specific output on the audio player or amplifier, and it was paired to a matching wireless receiver + amplifier that could power two speakers.

Philips LX3950 setup

The sticker specifies that the transmitter operates at 864MHz.

Inside view

Philips AD906WA

There are 3 PCBs :

PSU

This is a 150mm*75mm, single-layer PCB. It looks like there are 2 flyback supplies, one with a small transformer, likely for a low-power output, and one with a larger transformer and two outputs, likely for the power amplifier.

Interestingly, there’s no monolithic IC. The control-side only has semiconductors in SOT-23 package.

PSU board

Specifications

The sticker specifies the following data:

Connectors

There are 3 connectors on the PCB:

J2 pinout

Pin Wire color Signal
J2.1 Yellow -29.5V
J2.2 Black GND
J2.3 Black GND
J2.4 Red +29.5V

J3 pinout

Pin Wire color Signal
J3.1 Yellow PG?
J3.2 Black GND
J3.3 Red 10.0V

The signal on the pin 1 seems to act as a power good signal. This would need to be confirmed.

PCB markings

Amplifier

This is a 100mm*90mm, dual-layer PCB with a heatsink.

Amplifier

Connectors

1100 pinout

  1. Power output L
  2. GND
  3. GND
  4. Power output R

1104 pinout

Warning the markings are reversed compared to the PSU.

  1. +29.5V
  2. GND
  3. GND
  4. -29.5V

1106 pinout

  1. Audio input R
  2. GND
  3. Audio input L
  4. 10V output
  5. GND
  6. ?
  7. Red LED input

1107 pinout

  1. 10V input
  2. GND
  3. PG input?

BOM identification

Item Type Manufacturer, PN
7100 Quad opamp Natsemi LM8373
7101 Dual power amplifier Philips TDA8920TH4

LEDs

PCB markings

Receiver Board

This is a 90mm*68mm, 4-layer PCB that has one JST connector, one antenna, one RF ASIC in a metal shield, one opamps, one MCU, two analog ASICs, and one unknown chip.

Receiver board
Receiver board

1790 connector pinout

  1. Audio output R
  2. GND
  3. Audio output L
  4. 10V input
  5. GND
  6. ? (3V when powered-on)
  7. Red LED output

BOM identification

Item Type Manufacturer, PN
7710 PLL, IF demuxer Sanyo LA18365
7750 8-bit MCU PIC12C5086
? I²C-programmable PLL NXP TSA5060ATS7 4MHz crystal
7770 Audio decompressor, AGC Onsemi SA572D8
7780 Dual opamp JRC 40659
7790 Unreadable ST ??C80

PCB markings

Usability

The transmitter isn’t designed to operate without its Philips LX3950W/0110, which I don’t have, so using the receiver as intended looks compromised.

However, the amplifier works without the RF part, by connecting analog audio signals on the connector 1106: L-R signals on pins 1 and 3, and GND on pin 2.

Funnily, the specsheet gives the “Output power (RMS): 5 x 45 W”11 and the amplifier’s datasheed specifies a maximum power of 70W for each channel, when the receiver can only draw 25W from the power outlet and its PSU delivers 9.44W on its +/- 29.5V rails. That looks questionable.

This is a Class D amplifier, which explains why there’s a low-pass filter on the output, and why the heatsink is rather small for the advertised power.

References

  1. Philips LX3950W/01 specsheet↩︎

  2. Philips LX3950W/01 manual↩︎

  3. National Semiconductor LM837 datasheet↩︎

  4. TDA8920B datasheet↩︎

  5. Sanyo LA1836 datasheet↩︎

  6. Microchip PIC12C508 datasheet↩︎

  7. NXP TSA5060ATS datasheet↩︎

  8. NXP SA572D datasheet↩︎

  9. JRC 4565 datasheet↩︎

  10. Philips LX3950W/01 manual↩︎

  11. Philips LX3950W/01 specsheet↩︎

Electronics Électronique puissance semiconducteur semiconductors power Hardware CPE INSA Xavier Bourgeois

Xavier

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