Yes, but not to be _too_ insistent, when did it end? When were the last of the 2 tracks listed? I mean, were there any smaller labels that soldiered on with the format well into the 60s for example? I know some of the majors issued in both formats, but did they do it "serial" or "parallel" at least for some period.
BTW, the 1st Ampex 2 track inline home deck was based on the 600 series transport. It was called the 612 and could be used with 2ea. 620 powered speakers for a complete portable stereo playback system.
http://reel2reeltexas.com/vinAd56Ampex612Rev.jpgYes, I have one, along with the speakers - in need of restoration - of course...
There was also apparently a version in furniture finish wooden cabinets as well.
(see lower right corner of 1st image or this one -
http://reel2reeltexas.com/vinAd56Ampex612-1.jpgI think these would qualify as the first stereophonic devices for home playback - except if VM had a mono recorder with stereo companion amp / speaker out before that. It would have been staggered format as was the Magnecord which was THE 1st stereo recorder I think.
OK, from the Voice of Music website faq -
Q7-5: I have a switch on my V-M tape recorder with two positions called ?Stacked? and ?Staggered?. What does it do?
A7-5: First, a little history. The very first stereo format was on reel to reel tape! V-M Corporation offered a conversion kit for the venerable Model 700 in 1955 - some three years before stereo records and five years before stereo FM broadcasts! The first format? Very simple - take a second half track monaural head, turn it upside down, and mount it to the right of the existing monaural head. Connect it up with another pre-amp and you have the ?staggered? stereo tape format! The tapes were recorded with the starting points of the ?L? and ?R? tracks ?staggered? so that both signals would be in sync when picked up by the playback heads. This format is also called ?offset?. In 1958, as magnetic head manufacturing capabilities improved, the ?stacked? or ?in-line? format was invented - and remained the broadcast standard for many years - the so-called ?half track stereo? format. The V-M Model 714 was a hit because it had a switch to play both the newer ?stacked? and older ?staggered? formats. In November of 1959, V-M brought out the Model 720, one of the first on the market to play the new ?quarter track? stereo tapes.
aaand a reference to the Magnecord PT6-BN (for binaural) tape machine, which while not a consumer machine, seems to have pre-dated all. -
http://userwww.sfsu.edu/~hl/s.html