I've just got hold of a BR-4 and I'm aware this a discontinued product line, but if anybody here can help, that would be great please!

I'm going to be using this mostly just as a 'notepad' portable device and practice tool. If I wanted to do serious recording, I'd use my VS-1680. But as a small convenient, portable unit, it should be great! I've imported an MP3 file and am playing along with it. But I can't get the guitar level as I play along anywhere near the volume of the MP3 level. And following the manual is not working. Any ideas please?

Also, in general, where is the best place online to discuss the BR-4, or is it so old that it is not covered?