Hi, new to this forum.

I currently have Alpine MDA-7755R and CDA-5755 installed, I wish to upgrade to a unit that has USB mp3 function.

Does the IDA-xxxx unit compatible with CDA-5755? Can I still keep the CDA-5755 running as a EQ?

What is the best option? I don't wanna spend alot of money to upgrade. I just wanna play mp3 from a USB memory stick.