You've asked a bunch of questions that have been discussed here many
times, and it is tough to go through it all again.  Last question first,
overdubbing was possible way before tape recording.  It was common
practice in film production, and was even done on disc.  Even Les Paul
was doing it on disc before he started using tape.

In a quick oversimplified paragraph, in general, broadcasters started
using tape before the record companies.  Jack Mullen was recording Bing
Crosby's Philco Radio Time from the second season on tape -- the first
season was recorded and edited on disc.  ABC did their Daylight Saving
Time delay recordings on tape in 48.  For various reasons the major
record companies stayed with disc mastering into 1950-51 with occasional
uses of tape from 49 on.  But all the first year or two of LPs were disc
dubs with one major exception.  Murrow & Friendly's "I Can Hear It Now"
was tape mastered and edited, with release in late Nov 1948 on LP & 78. 
"South Pacific" is said to be Columbia's first major session with tape
used as a back-up in 49.  One of the CDs was issued off the tape, but
had to be recalled because they used a shortened take of "Carefully
Taught".  I think they went back to the disc masters after that for the
CDs.  Tape was used more in 50 and 51, but by 52 and 53 just about
everything was being mastered on tape.

There have been books written on the equipment and there are plenty of
websites.  The Brush Soundmirror was one of the first portable machines
in 1947, and RangerTone, Magnacord, Stetchel-Carlson, and of course
AMPEX followed in the next year, among others.

Mike Biel  [log in to unmask]

-------- Original Message --------
Subject: [ARSCLIST] Magnetic Tape/Recorders
From: rod smear <[log in to unmask]>
Date: Thu, June 21, 2012 9:57 pm
To: [log in to unmask]

Reading about the Spanish Civil War here, I'm reminded of a book I've
finished reading, called ZigZag, about WW II british spy/espionage, and
to wondering about the German magnetic tape machines that were found in 
Germany during/after the war. What were the first U.S. record companies
use this medium for recording? When? Anyone know the progression of
in this field? Equipment? Wasn't this the beginning of having the
to overdub easily?