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
Regards Fleib,
Here is the Feikert Speed App for the VPI Direct as published by Fremer in Stereophile and
here is the corresponding one for my TT-101.
Now all the Raw Frequency and Lowpass-Filtered Frequency figures are near identical for both turntables yet look at the General Mean Frequency comparison figures.....
The VPI Direct is 4.5 Hz above the 3150Hz Test Tone Frequency whilst the TT-101 is spot on.
Oh I know 4.5 Hz is tiny and probably irrelevant in the scheme of things BUT.....the VPI is using the most expensive and sophisticated motor for this application currently available and has 35 years of computer advanced technology to draw on yet can't match the accuracy of the 35-40 year design work of the Japanese Victor engineers...😡
But these Charts are not the most revealing part of the Feikert Speed App.
Here is the real time analogue print-out of the actual sinewave produced by the VPI Direct whilst tracking the 3150 Hz Test Tone. Ignoring the fact that it is well above the 3150 Hz frequency line.....observe the continually varying pitch of the mean frequency (a straight line is theoretically perfect) as it drops and raises tone. THIS is the real analogue graphic of the true speed-constancy performance of the test turntable.
Here is the Frequency Chart of my TT-101 and here is the long-term frequency chart of my TT-101.
Now tell me what you see and how the world of audio technology has improved over the last half century.....❓😎
Well, that is interesting. Maybe it's harder to correct speed inconsistencies of a 20 lb. platter? I don't think electronics has ever been VPI's long suit and this technology hasn't changed in the last 35 years. Harry is an old plinth builder, ironically for JVC.

You wouldn't by any chance have those charts for the TT81 and 71?
Regards,
I don't have charts for the other Victors yet but here is a video of the TT-81 under the Timeline with three arms going on and off and showing no deviation of the laser on the wall mark.
Based on this evidence and the fact that the TT-81 employs the identical forward and backward speed monitoring of the TT-101....I believe the Feikert figures would be similar.
Hi Henry,
According to VintageKnob, the TT81 does not have the double bidirectional servo. The 101 has a second quartz locked servo outside of the drive to compare phase. Looking at absolute speed, it doesn't seem to make much difference?

I think there's something to be said for a 20.lb platter on a DD. Can't say I've heard the VPI Direct, but I wouldn't dismiss it on that basis.
On the other hand, $30K would buy a bunch of Victors.
Regards,
Hi Fleib,
According to Vinyl Engine and the Victor TT-81 Service Manual....
Servo system: Quartz-locked positive and negative servo control
Vintage Knob appears to be wrong.....
I think there's something to be said for a 20.lb platter on a DD.
I haven't heard anything said that is supported by solid evidence...?
If you're going to monitor and control a platter as swiftly and effectively as possible, it seems sensible to make it as light as possible whilst accomplishing its other duties.
That's what Victor has done within its design objectives whilst Technics chose another with their SP10 MkIII and Kenwood yet another with their L-07D and Pioneer another with their Exclusive P3.
The fact is that there are so many good and great vintage DD Japanese turntables still in existence that anyone wanting to hear what one can do for his system, need not wait (possibly in vain) for the next great modern iteration of this drive choice.
It will almost certainly not be better than those mentioned whilst almost certainly will cost multiples more.