Tape Recorders

I recently purchased a second-hand Tandberg reel-to-reel tape machine and I'm having difficulties connecting it to my external hi-fi...

Could you explain the subtle differences between all the different variants of Dolby — A, B, C, HX and SR?

Back in 1986-7, there was an ad for an amazing and inexpensive technique which, it claimed, added many more audio tracks to your eight-track reel-to-reel tape machine. How did it work?