Just a matter of curiosity--what was the advantage of 150 ohm lines?
600 ohms was the standard for telco lines, including program grade lines. Wes Leatherock snipped-for-privacy@aol.com snipped-for-privacy@yahoo.com ***** Moderator's Note *****I'm always tempted to answer these sorts of questions myself - I worked on the "Radio" board, after all - but then I realize that a lot of the things I "know" about program audio lines are just memories of the way we did things, and I'm not sure of the technical basis.
Let's see: impedance varies with frequency, so (I'm guessing) I think
150 ohms is closer to the impedance at the upper frequencies, thus giving a boost to the "high end" tones, and making equalization easier. Come to think of it, that would be _part_ of the equalization, wouldn't it?