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Old 6th Jul 2019, 11:54 pm   #10
Lucien Nunes
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Join Date: Apr 2008
Location: London, UK.
Posts: 1,756
Default Re: How to set the speed on cassette decks.

I remember making my first speed test tape at school, when I had just acquired and repaired a Sony TC186 with a faulty motor. I recorded a continuous tone of no particular frequency for 10 minutes or so. I got a good quality tape measure and marked out as accurately as possible 112.5 inches along a lab bench (1 minute run time) and 15 second subdivisions. I pulled the tape out of the cassette, laid it oxide-up along the bench, and at each mark make a momentary erasure using the end of a paperclip wrapped around the tip of my demagnetiser. I also marked the back to align the next length, taking care not to introduce cumulative errors, for a total of ten minutes run time.

When played, the erased sections made clear pips which I timed with a stopwatch. The error when checked over the full ten minutes would have been miniscule, although most motors could not be adjusted that precisely. Obviously it gave no clue as to the wow and flutter, but I was really just after setting the speed on an otherwise working machine.
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