I have this old AMP I dug out of the garage. Planning on firing her up and giving it a good cleaning. A friend gave it to me for labor a number of years ago and i just wired it up to a couple speakers in the garage.for tunes while working in there. It worked fine. It has 4 speakers select position calling it 4D. What I am not sure of is it a Quadraphonic Amplifier. I will be testing it and opening it up for pictures for anyone interested. It is a MADE IN USA product sold by a company in Minneapolis called Sound of Music. They also sold Speakers. Pretty much this is all I know. I believe the power is around 100W. it has the heft of a big power supply.