Arfa Daily wrote in message
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"N_Cook" wrote in message
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Ron wrote in message
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N_Cook wrote:
Ron wrote in message
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N_Cook wrote:
Arfa Daily wrote in message
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"N_Cook" wrote in message
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Set up a sig genny and test him out


Much easier to say the test tape is stretched.
Perhaps perfect pitch testing would only work by playing the likes of
JSB
Tocatta and Fugue in D major, not pure tones

How come I cannot google the rpm of an audio cassette capstan? A
calibrated
strobe and tipex mark on the capstan periphery should give a definite
answer
(assuming the spindle is clean and not worn).
It should be determinable from tape speed of 1 7/8 in per sec and
spindle
diameter, that is about 1.9mm, but what should it be to 0.1 percent
accuracy?



The rotational speed of a cassette capstan is not a fixed given. The
diameter of capstans vary from machine to machine, and the correct speed
of
tape transport is then a function of how fast you drive the capstan round.
The reference in my strobe tape, is indeed the mains. I have been using
this
tape for many many years, and I have file://never// had anyone complain
that the
speed of their machine is off, after I have used it to set one up. Konig
must think that the mains is a good enough reference, otherwise, there
would
be no point in them marketing the tape for the purpose of setting up
speed.
Exception to this. As Ron said, very occasionally, when an owner has
recorded tapes when the machine was running at the 'wrong' speed ...

Arfa

Arfa




http://www.dynamicdemand.co.uk/grid.htm
Wokingham, Surrey, UK monitored mains frequency,
is instructive, try it in the middle of a national televised football match
or similar


spindle consistency
Not from my random sample of 8 audio cassette capstan spindles, all were
1.9mm or a bit lower say 1.89, with no cleaning etc, just as found.
If 1.9mm then rotational speed of 478.72 rpm and if the specified diameter
(cannot even find that) is 0.075 inches (bit less than 1.9mm) then speed is
477.46 rpm for 15/7 ips.
Googling including "478" or "477" throws up nothing, googling on rev/sec not
possible in like manner


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/