Bluetooth audio adapter cuts out my EQ

[Simos68]

I regularly use my Sony Xperia XZ3 conected via Bluetooth to my amplifier to listen to my music, however I have noticed that the Bluetooth dongle for some reason blocks the audio output from my graphic equalizer and renders it useless. 

I've tried 3 different types of USB cable devices and have had the same issue.

Sansui stereo graphic equalizer 3100.

Kenwood KA 3020 Special edition upgrade.

I purchased the kenwood amp because it had a Bluetooth upgrade option, usually I play my music via the Aux input through the equalizer with a 3.5mm to phono lead, have I lost you yet!

• Confusing, basically the Graphic Equalizer doesn't work when I use the Bluetooth port on the amplifier, all the lights light up and so does the spectrum but I can't adjust the frequencies. Strange, any ideas please guys would be much appreciated.
• Simon.