I have 2 AdCom 80’s vintage amps. 600W each. Counterpoint tube preamp. I use my iPhone for music source through an Apple router then to a DAC via fiber to the preamp. 4 Bose 901’s from the 70’s with 10 gauge wire. Sounds amazing but I was blasting out tunes and lost my LH channel. Any ideas? Blew my DAC? Or?... any suggestions greatly appreciated! Randy