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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Cassette tape speed adjustment
Assuming my test tape is stretched (I doubt it , as it would have to be even
stretch the whole length). I normally test speed monaurally so the beats are unmistakable. That is 1KHz test tape output and floating accurate 1KHz sine signal both fed into one headphone cup. Easily gives 0.1 percent resolution (assuming test tape is ok). If I record accurate 1KHz tone onto a blank tape for exactly ( to human reaction time accuracy) 100 seconds. Then replay for beats of 1Hz or so and output lasts for 100 seconds +/- reaction time then is the speed correct? I suspect that repeating this process with the speed regulator changed , say 5 percent, would also give "correct" speed, that time also Does anyone know how much effect types and thickness (play duration C30 to C90) have on replay speed perhaps in conjunction with too soft or too hard pinch wheel rubber ? |
#2
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Cassette tape speed adjustment
On Tue, 8 Dec 2009 16:32:52 -0000, N_Cook wrote:
Assuming my test tape is stretched (I doubt it , as it would have to be even stretch the whole length). I normally test speed monaurally so the beats are unmistakable. That is 1KHz test tape output and floating accurate 1KHz sine signal both fed into one headphone cup. Easily gives 0.1 percent resolution (assuming test tape is ok). If I record accurate 1KHz tone onto a blank tape for exactly ( to human reaction time accuracy) 100 seconds. Then replay for beats of 1Hz or so and output lasts for 100 seconds +/- reaction time then is the speed correct? I suspect that repeating this process with the speed regulator changed , say 5 percent, would also give "correct" speed, that time also Does anyone know how much effect types and thickness (play duration C30 to C90) have on replay speed perhaps in conjunction with too soft or too hard pinch wheel rubber ? none at all. |
#3
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Cassette tape speed adjustment
AZ Nomad wrote:
On Tue, 8 Dec 2009 16:32:52 -0000, N_Cook wrote: Assuming my test tape is stretched (I doubt it , as it would have to be even stretch the whole length). I normally test speed monaurally so the beats are unmistakable. That is 1KHz test tape output and floating accurate 1KHz sine signal both fed into one headphone cup. Easily gives 0.1 percent resolution (assuming test tape is ok). If I record accurate 1KHz tone onto a blank tape for exactly ( to human reaction time accuracy) 100 seconds. Then replay for beats of 1Hz or so and output lasts for 100 seconds +/- reaction time then is the speed correct? I suspect that repeating this process with the speed regulator changed , say 5 percent, would also give "correct" speed, that time also Does anyone know how much effect types and thickness (play duration C30 to C90) have on replay speed perhaps in conjunction with too soft or too hard pinch wheel rubber ? none at all. Tape speed depends on the rotational speed and diameter of the capstan. On a properly maintained deck all other factors are irrelevant. Ron(UK) |
#4
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Cassette tape speed adjustment
"N_Cook" wrote in message ... Assuming my test tape is stretched (I doubt it , as it would have to be even stretch the whole length). I normally test speed monaurally so the beats are unmistakable. That is 1KHz test tape output and floating accurate 1KHz sine signal both fed into one headphone cup. Easily gives 0.1 percent resolution (assuming test tape is ok). If I record accurate 1KHz tone onto a blank tape for exactly ( to human reaction time accuracy) 100 seconds. Then replay for beats of 1Hz or so and output lasts for 100 seconds +/- reaction time then is the speed correct? I suspect that repeating this process with the speed regulator changed , say 5 percent, would also give "correct" speed, that time also Does anyone know how much effect types and thickness (play duration C30 to C90) have on replay speed perhaps in conjunction with too soft or too hard pinch wheel rubber ? I just use a speed test tape from Konig. It has a strobe wheel behind what would normally be the tape viewing window. Very easy to see an accurate setting for the speed, and virtually instant comparison between forward and reverse. Also easy to see any cyclic variations in speed, or long term drift. Arfa |
#5
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Cassette tape speed adjustment
Arfa Daily wrote in message
... "N_Cook" wrote in message ... Assuming my test tape is stretched (I doubt it , as it would have to be even stretch the whole length). I normally test speed monaurally so the beats are unmistakable. That is 1KHz test tape output and floating accurate 1KHz sine signal both fed into one headphone cup. Easily gives 0.1 percent resolution (assuming test tape is ok). If I record accurate 1KHz tone onto a blank tape for exactly ( to human reaction time accuracy) 100 seconds. Then replay for beats of 1Hz or so and output lasts for 100 seconds +/- reaction time then is the speed correct? I suspect that repeating this process with the speed regulator changed , say 5 percent, would also give "correct" speed, that time also Does anyone know how much effect types and thickness (play duration C30 to C90) have on replay speed perhaps in conjunction with too soft or too hard pinch wheel rubber ? I just use a speed test tape from Konig. It has a strobe wheel behind what would normally be the tape viewing window. Very easy to see an accurate setting for the speed, and virtually instant comparison between forward and reverse. Also easy to see any cyclic variations in speed, or long term drift. Arfa Strobing of what rotational part against what reference? How do you know if the tape is stretched? |
#6
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Cassette tape speed adjustment
N_Cook wrote:
Arfa Daily wrote in message ... "N_Cook" wrote in message ... Assuming my test tape is stretched (I doubt it , as it would have to be even stretch the whole length). I normally test speed monaurally so the beats are unmistakable. That is 1KHz test tape output and floating accurate 1KHz sine signal both fed into one headphone cup. Easily gives 0.1 percent resolution (assuming test tape is ok). If I record accurate 1KHz tone onto a blank tape for exactly ( to human reaction time accuracy) 100 seconds. Then replay for beats of 1Hz or so and output lasts for 100 seconds +/- reaction time then is the speed correct? I suspect that repeating this process with the speed regulator changed , say 5 percent, would also give "correct" speed, that time also Does anyone know how much effect types and thickness (play duration C30 to C90) have on replay speed perhaps in conjunction with too soft or too hard pinch wheel rubber ? I just use a speed test tape from Konig. It has a strobe wheel behind what would normally be the tape viewing window. Very easy to see an accurate setting for the speed, and virtually instant comparison between forward and reverse. Also easy to see any cyclic variations in speed, or long term drift. Arfa Strobing of what rotational part against what reference? How do you know if the tape is stretched? It doesn't matter if the tape is stretched, the tape speed is governed by the rotational speed of the capstan. If the tape were stretched you would have to adjust the capstan speed to get the right playback pitch on that particular tape tho I doubt it would be very noticable. Somewhere I still have a cassette with 100 hz on one side and 8k on the other, plus a strobe disk visible through the window on the 100 hz side. You set the capstan speed by measuring the 100 hz on playback. The 8k is for head alignment. The strobe disk is driven by the capstan. Quite often the playback speed would be adjusted to be correct, followed by complaints from the customer that all his tapes now seem to play at the wrong speed! Ron(UK) |
#7
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Cassette tape speed adjustment
Ron wrote in message
... N_Cook wrote: Arfa Daily wrote in message ... "N_Cook" wrote in message ... Assuming my test tape is stretched (I doubt it , as it would have to be even stretch the whole length). I normally test speed monaurally so the beats are unmistakable. That is 1KHz test tape output and floating accurate 1KHz sine signal both fed into one headphone cup. Easily gives 0.1 percent resolution (assuming test tape is ok). If I record accurate 1KHz tone onto a blank tape for exactly ( to human reaction time accuracy) 100 seconds. Then replay for beats of 1Hz or so and output lasts for 100 seconds +/- reaction time then is the speed correct? I suspect that repeating this process with the speed regulator changed , say 5 percent, would also give "correct" speed, that time also Does anyone know how much effect types and thickness (play duration C30 to C90) have on replay speed perhaps in conjunction with too soft or too hard pinch wheel rubber ? I just use a speed test tape from Konig. It has a strobe wheel behind what would normally be the tape viewing window. Very easy to see an accurate setting for the speed, and virtually instant comparison between forward and reverse. Also easy to see any cyclic variations in speed, or long term drift. Arfa Strobing of what rotational part against what reference? How do you know if the tape is stretched? It doesn't matter if the tape is stretched, the tape speed is governed by the rotational speed of the capstan. If the tape were stretched you would have to adjust the capstan speed to get the right playback pitch on that particular tape tho I doubt it would be very noticable. Somewhere I still have a cassette with 100 hz on one side and 8k on the other, plus a strobe disk visible through the window on the 100 hz side. You set the capstan speed by measuring the 100 hz on playback. The 8k is for head alignment. The strobe disk is driven by the capstan. Quite often the playback speed would be adjusted to be correct, followed by complaints from the customer that all his tapes now seem to play at the wrong speed! Ron(UK) Whatever touches the capstan spindle could wear and if the reference source for stobing is a mains lamp, that is only set for (UK) 50x60x60 cycles per hour (for synchronous clocks) and short term only +/-0.5 percent targetted frequency. I have the related problem of someone who says he has perfect pitch. |
#8
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Cassette tape speed adjustment
N_Cook wrote:
Ron wrote in message ... N_Cook wrote: Arfa Daily wrote in message ... "N_Cook" wrote in message ... Assuming my test tape is stretched (I doubt it , as it would have to be even stretch the whole length). I normally test speed monaurally so the beats are unmistakable. That is 1KHz test tape output and floating accurate 1KHz sine signal both fed into one headphone cup. Easily gives 0.1 percent resolution (assuming test tape is ok). If I record accurate 1KHz tone onto a blank tape for exactly ( to human reaction time accuracy) 100 seconds. Then replay for beats of 1Hz or so and output lasts for 100 seconds +/- reaction time then is the speed correct? I suspect that repeating this process with the speed regulator changed , say 5 percent, would also give "correct" speed, that time also Does anyone know how much effect types and thickness (play duration C30 to C90) have on replay speed perhaps in conjunction with too soft or too hard pinch wheel rubber ? I just use a speed test tape from Konig. It has a strobe wheel behind what would normally be the tape viewing window. Very easy to see an accurate setting for the speed, and virtually instant comparison between forward and reverse. Also easy to see any cyclic variations in speed, or long term drift. Arfa Strobing of what rotational part against what reference? How do you know if the tape is stretched? It doesn't matter if the tape is stretched, the tape speed is governed by the rotational speed of the capstan. If the tape were stretched you would have to adjust the capstan speed to get the right playback pitch on that particular tape tho I doubt it would be very noticable. Somewhere I still have a cassette with 100 hz on one side and 8k on the other, plus a strobe disk visible through the window on the 100 hz side. You set the capstan speed by measuring the 100 hz on playback. The 8k is for head alignment. The strobe disk is driven by the capstan. Quite often the playback speed would be adjusted to be correct, followed by complaints from the customer that all his tapes now seem to play at the wrong speed! Ron(UK) Whatever touches the capstan spindle could wear and if the reference source for stobing is a mains lamp, that is only set for (UK) 50x60x60 cycles per hour (for synchronous clocks) and short term only +/-0.5 percent targetted frequency. I have the related problem of someone who says he has perfect pitch. Set up a sig genny and test him out |
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