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Vintage DD turntables. Are we living dangerously?

I have just acquired a 32 year old JVC/Victor TT-101 DD turntable after having its lesser brother, the TT-81 for the last year.
TT-101
This is one of the great DD designs made at a time when the giant Japanese electronics companies like Technics, Denon, JVC/Victor and Pioneer could pour millions of dollars into 'flagship' models to 'enhance' their lower range models which often sold in the millions.
Because of their complexity however.......if they malfunction.....parts are 'unobtanium'....and they often cannot be repaired.
halcro
fleib
1,124 posts
 
Dover,
"Speed is never absolute. It is always measured from a point of reference. The planet is rotating, the measured speed on your platter is relative to the rotation of the planet - it cannot be absolute."

We're talking rotational speed not land/air/sea speed. It's as absolute as the timing of a minute.
Regards,
fleib
1,124 posts
 
RK,
"Look at the raw trace for the WE8000.
Start at the first lower min freq, just above 3130 hz. Other than the max at around 3164hz, count every sharp change in direction until immediately before the next min of around 3130 hz again.
I count 14. The platter changes speed 14 times during that single revolution."

A tone is a vibration, a sine wave, not a straight line on a scope. You have to compare to a "pure" tone generated for 3150Hz.
Regards,
lewm
13,844 posts
 
If Dover and Richard (and Fleib) were to refrain from commenting, we would all be the poorer for it, and this fun thread might be dead. Carry on, gentlemen.
halcro's avatar
halcro OP
2,664 posts
 
For those belt-drive turntable owners who are concerned at the 'servo-control' jagged spikes on their Feikert Frequency Chart, here is a what Marcus Ribi from Feikert Platterspeed has to say about the change in the software....
The approximate sine wave form of the chart is resulting from eccentricity of the record. A normal measurement of WOW and flutter with a perfectly centered record will NOT show such a wave form, but a more random spiky form instead. That's what the spikes are coming from: it's a superposition of eccentricity and "real" WOW and flutter. Measurement of WOW and flutter then tries to best filter away the regular changes comig from record eccentricity to provide best results.
fleib
1,124 posts
 
I wonder how accurate this is. The waveform peaks at +16Hz and bottoms at -20Hz. That's a spread of 36Hz, a little more than 1%.
A scope or a meter with a frequency counter could be used to check results.

Another fly in the ointment - Werner Ogries EE, has reported calibration errors in both HFN and Analog Productions test records. Not sure of all the gory details.
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