Vintage DD turntables. Are we living dangerously?

Dear @cleeds : You are rigth the DP-80 never was manufactured to run at 120VAC . My unit comes exaxctly as yours but the 75 comes with no step down transformer.

I think that the unit that bougth lewm was modified in some ways to run at 120VAC.

I don't know other DP-80 owners but my unit from new ( and the 75 too. )  always play as " new " and I have in stock status. 

Btw, maybe the 101 design is very good but the JVC excecution was not at levels of Denon or Technics and even its manufacturer specs are inferior to the Denon's.

101:  w&f  0.020%    s/n   75db  speed accuracy   0.002%

DP-75:  w/f   0.15%    s/n   80db   speed accuracy    0.002%

Even the JVC 71 has better spec than the 101 in s/n db. Main difference between the 71 and 81 is the double/bi-directional servo that does not comes in the 71 and of course the higher price.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Dear Raul,

If you heard no differences between the TT-71 and TT-81....then something was very wrong.
Either the TT-81 was faulty, the system it was connected to was not revealing or you are simply unable to hear discriminately  🤔
The differences between the TT-81 and TT-71 are far more marked than those between the TT-81 and TT-101 starting with the bi-directional servo control which is a patented breakthrough in DD technology and is the reason that the Yamaha GT-2000 (which uses the same Victor bi-directional servo motor) is so desirable.

Halcro, do you have the patent number?  The TT-101 service manual describes the bi-directional servo as the differences between a simple F/V servo which has to coast to slow down, and a PLL which is bi-directional in this sense, and is something every 'table with a PLL (aka Quartz Locked) has.  

Dear @halcro : Fortunatelly the JVC chasis is very similar to my Denons and I mounted both in the custom plinths of both Denons with the same tonearm. Maybe you are rigth and I am " simple unable to hear discriminately..".

You need to grow-up in your knowledge and ignorance levels. I don't know what happens with you because I think that in this same thread ( if not in other where you posted too. ) I posted that that " touted " bi-directional servo in the JVC and that for you is the " penultimate wonder " on TT was a unique in JVC designs when was and not is  ( I don't know where you try to learn or with what kind of audio advisors you are surrounded. ) that way because not only what jp posted but Denon stated about that bi-directional servo in its DP-70M and latter on the DP70L models.

I assume that you think that discovered the " black thread " with the JVC. Wrong, nothing special. It's one units in the  japanese TTs bunch and that's all. Obviously that when some one ignore audio information can makes a misunderstanding in this and other audio subjects.

So, what are you talking about?

Better than that please do it a favor let it go the JVC in change for the new Technics units.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Perhaps this is what Halcro is referring to: https://patents.google.com/patent/US4888564A/en?q=phase&q=lock+loop&oq=phase+lock+loop. From a brief glance, it looks like what is described in the tt101's service manual. Perhaps it is related to the pitch control capabilities that the tt101 and tt81 possess and their other turntables, e.g. tt 71, don't. I leave it to those with superior technical minds to render judgment.

For those who prefer their information concatenated with pretty pictures, Vinyl Engine has several jvc brochures from the late 70's which describe the merits of their line of quartz turntables (along with the 'numbers' for each turntable in a convenient side by side format).

One other tidbit relating to the differences between the tt101 and the tt 81/71 is this: only the 101 has a coreless motor. If one is to praise Technics for utilizing this type of motor in their new design (they are terribly late to the game, no?), then one should acknowledge at the very least that the 101 should sound different, and likely better, than its siblings. To dismiss the 101 after listening only to its siblings therefore strikes me as a logical error.