At 04:30 PM 4/18/2003 -0500, Parker Dinkins wrote:
>Dolby B was designed for use with audiocassettes. Dolby A was designed for
>open reel tapes, and the hardware is available in the market. If you have
>Dolby B open reel tapes they were probably created to dub cassettes.
That is partially true. HOWEVER, it may be more precise to say that Dolby B
was created as a consumer format while Dolby A was a professional format.
Dolby B has been incorporated in many reel-to-reel consumer machines. I can
say for certain that the ReVox A77 was available in that configuration
because I own one.
There was some problem surrounding a ReVox 7.5/15, two-track Dolby B
machine involving a friend of mine. I think Studer/ReVox determined that it
was against their license with Dolby to manufacture such a machine, but the
haze of time clouds the details.
Other reel machines also included Dolby B processing. I think Akai and
Tandberg were on that list. I'm not sure about Teac.
Advent, early on, sold add-on Dolby B processors (I had two at one time),
and Teac sold the model AN-180 (top of the line) -- I have one. These were
both positioned to use with reels.
Finally, Barclay Crocker duplicated at least two Vanguard titles on
quarter-track 7.5 in/s Dolby B reels (I have them in my collection).
So, I do think that Dolby B will exist on reels both in a commercial
embodiment as well as in a consumer-recorded environment. Many of my early
recordings were accomplished with Dolby B--I didn't get my Dolby A's until
circa 1977 while I was using Dolby B from circa 1973 for recording to reel.
With all that said, I still wouldn't preclude Parker's theory that the tape
in question might be a duplication master. However, when I donate the
master tapes of several seasons of the Great Neck Symphony Orchestra, some
of those will be Dolby B and some may even be dbx II (GAK).
In fact, this proliferation of formats:
in my collection -- and the fact that I understood the permutations -- was
one of the things that led me to this tape restoration "insanity" ;-)) I'm
now involved with.