10-10-08: JayteaYeah, but analog master tapes by the '80s had a s/n ratio of 100 dB or more. Even the studio master tapes of the '70s had an s/n of 80 and a few reached to 90dB or more.
By the way, arent most (if not all) vinyl reissues were re-mastered from "original master tape"?
But the s/n of a home Akai or Teac R2R at 7.5 ips was about 54-56 dB. The Tandbergs reached about 65dB and the Revox A77 WITH Dolby hit 66 dB.
A little later when Sony started using their ferrochrome formula for their best R2R machines, they achieved higher s/n figures, and had frequency response out beyond 45KHz. But by then the train was leaving the station and only the most die-hard enthusiasts were going that direction. Besides, 10.5" reels of 1/4" ferrochrome were VERY expensive for the day.
In my experience, whether 8-track, cassette, or 7.5 ips open reel tape, the prerecorded offerings from the major labels were on the cheap side. You seldom got a cassette that was screwed together like a top notch Maxell or TDK, and you didn't get prerecorded open reel tapes of the quality you could buy from 3M, Maxell, Sony, or TDK. They were often acetate instead of polyester, with a dull entry-level oxide coating.
As Eldartford points out, an entire 40-minute LP can be stamped in a matter of seconds, but a tape has to be duplicated serially, and if you try to speed up the process, you lose the upper octave. If you duplicate at 2x normal speed, both machines have to have linear response out to 40KHz to incur no loss of treble. And higher speed usually raises the noise level as well.
When you look at the various tape formats vs. LP, and balance sound quality against efficiency of manufacture, the LP stands alone. It's easily the best sounding analog source that can be reproduced in about a minute.