XNV-L77BT strange behaviour with USB connection

[k1300s]

I would like to know if other people encounter the same issue. When I use bluetooth streaming or USB connection I have sound on the car speakers only if I switch  the AF (alternate frequencies for RDS radio) on.

Did you already encounter this kind of issue ?

Thanks a lot.

Regards.

A french L77BT user.

[alerenz27]

Guess you have an amp installed?

If so, you used the power antenna connection instead of the amp remote connection at the rear of the radio.