Reckhorn A409 - Power Amplifier & Active Low Pass for Subwoofer - Schematic wanted

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Reckhorn A409 - Power Amplifier & Active Low Pass for Subwoofer - Schematic wanted

I am looking for the schematic diagram for this device:
https://reckhorn.com/media/pdf/38/c1/38/A-409-Bedienungsanleitung_EN_DE.pdf
Thank you for upload.