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Sony RGB Encoder


S-Video & Composite A/V Circuit (C945 Based)

Purchase these parts as a kit

Purchase a layout PCB for easy assembly

This circuit reduces the component count of the old style 1815 circuit and features better color and better compatibility with modern HDTVs.

  • Parts List:
    • C1: 220uF, 6.3v electrolytic (chroma)
    • C2: 220uF, 6.3v electrolytic (composite video)
    • C3: 10uF, 6.3v electrolytic (mono audio)
    • T1: C945 (2SC945, KSC945, etc)
    • VR1: 500Ω - 2kΩ Potentiometer (luma)
    • VR2: 500Ω - 2kΩ Potentiometer (chroma)
    • VR3: 500Ω - 2kΩ Potentiometer (composite)

Try to connect your +5 and GND as closely as possible to the CXA1145 to avoid ground loops.

In the provided schematic, analog ground (Pin 1 & 24) as well as +5 (Pin 12) are shown.

  • For the variable resistors, common starting values are:
    • VR1: 33Ω
    • VR2: 75Ω
    • VR3: 75Ω

By using potentiometers instead of fixed resistors, you can tune the device to look best on your display.

The connection for monaural audio is shown. Stereo audio is system dependent.


Sony CXA1145P/M RGB Encoder

Sony CXA1145P/M RGB Encoder (Japanese)

Itri Erso ES71145 RGB Encoder (CXA1145 substitute, English)

S-Video Buffer Circuit (2SC1815 Based - DO NOT USE)

Providing this for posterity. DO NOT USE THIS CIRCUIT!

  • Parts List (Build twice - once for luma, once for chroma):
    • R1: 10k
    • R2: 10k
    • R3: 110k
    • R4: 110k
    • C1: 100uF, 6.3v (or higher) electrolytic
    • C2: .1uf ceramic
    • T1: 2SC1815*
    • VR1: 500Ω - 2kΩ Potentiometer

*An NTE85 is frequently cited as the transistor for this circuit. NTE typically makes substitute parts, not original parts. NTE85 is the replacement for the 2SC1815, except the NTE part is about 20 times the cost.