"The subwoofer is connected to my Anthem MRX HT receiver via LFE connector. No issues with digital sources of course. My phono preamp is a Rega Mini Fono A2D."
You should only use 1 LFE connection. If you connect IC's to the LFE out on your HT preamp, the other end should go to the line level input on your sub, not the LFE input. Try that first.
You may also want to try lowering the gain on your phono preamp, as well as checking the gain on the channel you are plugging it into. A lot of theatre processors have that ability. Also, I'm assuming that you are using the analog connections on your phono pre, and not the USB option.
You should only use 1 LFE connection. If you connect IC's to the LFE out on your HT preamp, the other end should go to the line level input on your sub, not the LFE input. Try that first.
You may also want to try lowering the gain on your phono preamp, as well as checking the gain on the channel you are plugging it into. A lot of theatre processors have that ability. Also, I'm assuming that you are using the analog connections on your phono pre, and not the USB option.