My home theater project got an update as I found stereo music center straight from the 70’s from the flea market. It includes LP- and cassette players, radio and supports Matrix 4-channel sound and external audio source (my computer at the time). I don’t have audio cassettes, so I don’t know if the player works. LP-player makes so odd sound, but I bet I could fix it if I wanted (I checked, there is spare parts available on internet), but I don’t have LP’s, and no plan of starting to collect those, so I think I won’t fix it. I ordered audio cable from amazon.co.uk, once it arrives I’ll test the system with my computer. In worst case I have bought expensive radio. Which is not completely a bad thing, as waiting for the cable to arrive, I have started to listening radio, first time in my life, and I like it! But I think the amplifier part must work, as the radio works, and I can use it to the original purpose, as an audio system to watch movies. I have to buy couple more speakers and I get a nice 4-channel audio for movies.