I have a Samsung A6 tablet running Android 5.1.1. The volume set in the CB music player defaults to about 65% and I have not been able to increase it. In Settings, I have changed the volume of my device to 100%, but the player remains limited to 65%. Even when I zoom in closely to the volume slider in the CB player, I can only choose volumes up to about 65%.
I have no problems when I use the CB music player on my laptop.
Scott