"Johnny B Good" wrote in message
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On Tue, 14 Feb 2017 17:57:47 +0200, Iain Churches wrote:

"Johnny B Good" wrote in message
...
On Sun, 12 Feb 2017 23:35:04 +0200, Iain Churches wrote:

"Jim Lesurf" wrote in message
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In article , Iain Churches
wrote:
Prerecorded cassettes were always something of a compromise
(high-speed loop-bin duplication) but towards the end of that era,
chrome tape with Dolby B was starting to sound pretty good.

That reminds me that there was at least one company who did 'real
time'
Cassette duplications for the sake of sound quality. I can't now
recall their name(s), though. Something like "White(something"
perhaps was one of them.

There were probably many. One I know of in North London was called
"SuperCassette" (original, eh?) They had a large room with dexion
shelves floor to ceiling with two or three realtime high-end cassette
recorders (Nakamichi or something similar) on each shelf. Each
"aisle"
was fed by its own "master recorder" (Revox A77) with a studio copy of
the master running at 15 ips. The cassettes sounded quite good!


I wonder, seeing as they were going to such an extreme, whether they
also ran the master and slaves in reverse to mitigate the phase delay
'distortion' effect on low frequency square wave test signals which
made such test signals look like triangle waves on playback when viewed
on an oscilloscope, or did they just accept that despite this very
visible departure from the original waveshape, no one could distinguish
the direct versus the phase distorted magnetic recording playback by
ear alone anyway? :-)

The system was a simple one, and only needed two young girls operators
to keep it running. As soon as the EOT switch clicked on the Revox one
of them walked along the row, ejecting the cassettes and putting in new
ones.
The other dabbed the Revox replay head with a spot of Isoprop, rewound
the"master" and then helped with the casette replacement.

I would hope the other YL would have done a *lot* more than just dab the
replay head alone with a "spot of isopropyl alcohol". Never mind the
replay head, you also have to decontaminate the rest of the tape path
components (guides, capstain(s), pinchwheel(s), erase and record heads,
*everything* the master tape has to negotiate in its transit between the
supply and take up reels) even when using the modern Japanese Maxell and
TDK master tape formulations which showed up the deficiencies of EMI,
Ampex and Scotch tape formulations that had once been regarded as leaders
in magnetic tape technology.

None of the cassette decks received any TLC in the
short time I watched the process. Though without
doubt they had a more thorough cleaning regime after
a fixed number of passes.

The master machines at the head of each aisle were
started at intervals, so that as soon as the tape finished
they were busy reloading, before moving to the next
aisle where the master was in the last few turns,
and repeating the process.

As the production level was far below that of a loop
bin system, it would have been interested to know how
much extra they could charge per cassette for enhanced
quality, and real-time copying.


Iain