preamps \u0026 power amps. pioneer sx-850 stereo receiver. radford monitor – 70\u0027s. hpm. we removed the driver and the front wall, and the bass tunnel from the back as a result, we had a nice box without one wall and with a round opening in the . wirecutter. sansui g-9000 stereo receiver. bose 301 speakers circa 1985 beautiful sound for modern music!.