I am puzzled why you are using the bluesound.
Cast direct from your tablet to the CCA.
I know that production of the CCA was stopped months ago, but you can still buy them.
I bought two, so that I always had a backup if needed.
Google Chromecast audio: analog and digital output
This digital output, however, requires an optical mini-jack cable to Toslink, which is not supplied. We can then associate the Google CCA with an external DAC.
Network audio player
WiFi 2.4 / 5 GHz b / g / n / ac (WEP, WPA / WPA2)
DAC Asahi Kasei 24 bit / 192 kHz
Line output and optical S / PDIF
Compatible with 100 mobile applications Android and iOS
Compatible Android, iOS, PC, Mac and Linux
Multiroom
24-bit / 96 kHz playback to S / PDIF output
Automatic update
Connections
1x micro-USB port (power supply)
1x line output mini-jack doubled S / PDIF optical
Supplied accessories
Short 3.5 mm mini-jack cable (14 cm), micro-USB to USB-A cable (1.7 m), mains charger