I have some RR tape machines that I got for "Payment"-besides money from radio stations for fixing their transmitters and such.Have a Magnecord,An Ampex 300,and an Otari MX10.Right now these machines are sort of packed away.They do still work.The Ampex has its orig tubed Rec/Pb amp and is mono full track.All broadcast machines-mon-stereo were full track-for ease of editing or splicing.No second "side".And they ran at 7.5,15,or even 30 IPS.-unlike home machines that ran at the lower speeds.These are also "3 motor"one motor for the capstan,the others for the reels.The only single motor machine used a lot for broadcast-commercial work were Ampex 600's mono or stereo.They had a very heavy duty belt and capstan driven system from one motor.They had tubed or SS Rec/PB amps-and were often packaged in "feild cases" for portable work.Same with Ampex 350-one case held the transport-the other the Rec/Pb amps.Another case held an amp and speaker.(PP 6V6!)