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isw

In article
d.invalid,
lid (Adrian Tuddenham) wrote:

Jeff Liebermann wrote:

On Thu, 29 Sep 2011 15:07:40 +0100,
lid (Adrian Tuddenham) wrote:

Does anyone happen to know the official speed of a Dictabelt?

Which maker and what model?
They followed the same speeds at record platters.
ips time
15 15 min
7 1/2 30 min
3 3/4 60 min
1 7/8 120 min

I think you have misunderstood the type of machine I am enquiring about.

[...]
It seems
to be around 6 inches per second or 30 belt revolutions per minute, but
there must be a proper specification somewhere.

30 rev/min = 0.5 rev/sec. At 12" per revolution, that's:
0.5 rev/sec * 12 in/rev = 6 in/sec.
Close enough to 7.5 ips.

It issignificantly below 7.5 ips. I need to know the manufacturer's
specifications as I am developing a playback machine for archival work,
where comparison between the actual speed and the 'official' speed can
yield useful historical information.

Any chance of there being any power-line hum in the recording? If there
is, that's your calibration. If not the fundamental, then maybe
harmonics ...

Isaac