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Ampex used an indirect drive on their first machines- Models 200 and 300. The fine speed adjustment for the capstan drive was accomplished by adding and subtracting the amount of drag applied to the rubber tire coupled through a flywheel to the capstan shaft.  A minimum warm up time of 5 minutes was needed before any adjustment to the drive was attempted.

A supplied strobe disc was used to determine the correct amount of drag.
It must have been difficult to maintain speed consistancy between machines , using this method.

No wonder later machines used the vastly superior direct capstan drive motor.

Bob Hodge

 



Robert Hodge,
Senior Engineer
Belfer Audio Archive
Syracuse University
222 Waverly Ave .
Syracuse N.Y. 13244-2010

315-443- 7971
FAX-315-443-4866

>>> [log in to unmask] 3/10/2006 10:59 PM >>>
"Richard L. Hess" wrote:

> In some respects, I think we can credit Jack Mullin as the earliest
> craft editor, working with scissors to edit Bing Crosby and Burl Ives
> shows in 1947 on his Magnetophon transports with his own electronics.
>
> And yes, you can hear some of them.

Even before then, MGM was editing on film to put together its soundtrack albums and
cut production numbers down to three minutes..some of those edits sound as if they
were done with an axe.

> Were the Columbia pitch changes due to start-of-reel/end-of-reel
> speed changes or what?

That must have been the reason. Some glaring ones: Dinu Lipatti's Chopin Waltzes,
very last track (side 1 I think), major pitch change right on the last note. EMI
finally corrected that on the CD issue but we had to put up with that pitch change
for over 30 years before that happened.

> The worst edit I ever did was when we had the organ blower on for the
> main take and then we did a pickup at the end and someone had turned
> the organ blower off....

The worst editing on a best-selling LP is on Vladimir Horowitz's so-called "live"
recording of the Rachmaninoff 3rd Concerto on RCA. Parts are from the rehearsal,
and the piano moves.

dl