i just recently bought a russuond sdb-4 ez from a lady who's in process of moving and getting rid of things she no longer needs. i bought it for $20 when i came across it while taking apart her entertainment center. it was in working order and ran to several speakers throughout the house. first thing i noticed is that it doesnt have a power supply cord at all. the front has 4 volume controls and each control has its own on/off button and an A/B button, the rear has 2 amp wire ports marked ( A & B ), each with 2 left & 2 right ports. to the left of that is 4 speaker wire ports marked ( 1,2,3,4, ), each with the left & right wire ports. my home system has surround sound with wire ports to hook up 2 pairs of speakers. i figured i was to run my home system A speakers to the amp A ports & the B speakers (the surround speakers) to the amp B ports. then attach the speakers to the speaker ports. for some reason it not putting out any sound, tried pushing front buttons but nothing. can someone explain what i might be doing wrong, or if my system is compatible with this device, and did i waste my $20. thanks for any advice.