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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.
128x128halcro
halcro's avatar
halcro OP
2,664 posts
 
Richardkrebs...
In other words, perfect speed would show just a sine wave symmetrically centred about the 3150hz line on the raw data graph.
Markus Ribi...
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.
Richardkrebs...
Sharp spikes on the raw trace... this is a servo in action!
richardkrebs
422 posts
 
Halcro.

Perhaps you misinterpreted my last post.
When I said "perfect speed" I did not mean "perfectly centered".

A real world test record, which is off centre, produces the sine wave. Speed errors are superimposed on this sine wave, as Markus says.

So with a real world test record running at perfect speed, we would get the results I described.

cheers.

Go the ABs!
halcro's avatar
halcro OP
2,664 posts
 
Perfect Speed?
Perfect Speed?
lewm
13,313 posts
 
Just a note from the peanut gallery:
Halcro, you and Richard are actually in agreement. The statement from Feickert (or whatever was the outside source) was that record eccentricity will produce a regular irregularity in the frequency, forming a sine wave around the center frequency. Since one is interested in wow and flutter due only to tt platter speed variations, that sine wave must be filtered out or subtracted from whatever is the actual wave form. The remainder would constitute w and f due to the tt only. Ideally, that would leave a straight line, if wow and flutter due to the tt were zero. I think we can all agree on that, including you and Richard.
dover
2,262 posts
 
Lewm -
No they are not in agreement. Halcro does not accept that the deviations in the sine wave are wow and flutter ( as explained by Feickert ). Richardkrebs argued that the spikes were speed corrections generated by the TT error correction, but they could be caused by many things, all we know is that they are speed deviations.

Other than eccentricity wow and flutter can be caused by imperfections in the record surface ( you must have heard of warp wow ) and tonearm/cartridge issues. So your statement that "The remainder would constitute w and f due to the tt only" is not correct.
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