Vintage DD turntables. Are we living dangerously?

You are totally wrong. From where you learned or I have to say ....) used Yamaha motors not JVC motors both are way different and measures different: 75db against 85db in the Yamaha.

Wrong.....

As only the Japanese can do, it was a co-operative effort designed by Yamaha in conjunction with Micro Seiki using a motor and motor control electronics from the Japan Victor engineer who designed the motor and motor control electronics for the TT-81.

Mostly Micro Seiki mechanicals and Victor electronics.

The 71/81 came with coreless motor, you have a misunderstanding.

 
Wrong......

TT-81

Motor: DC servomotor

Drive system: direct drive

Speeds: 33 and 45rpm

Speed detection: integrated frequency generator

Servo system: quartz locked positive and negative servo control

Starting time: within 1 second

Wow and flutter: 0.025% WRMS

Rumble: 63dB

Speed deviation: within 0.002%

Platter: 310mm diecast aluminium

Dimensions: 150 x 358 x 358mm

Weight: 8kg

TT-101

Motor: coreless DC servo motor

Drive system: direct drive

Speeds: 33 and 45rpm

Speed detection: integrated frequency generator

Servo system: quartz locked positive and negative servo control

Pitch control: +-6Hz

Starting time: within 0.6sec

Wow and flutter: within 0.02% WRMS

S/N: 75dB

Starting torque: 1.2kg/cm

Speed deviation: 0.002%

Load characteristics: 0% (with a 120g total tracking force)

Drift: 0.0004%

Platter: 310mm aluminium diecast

Dimensions: 150 x 358 x 358mm

Weight: 10kg

Sigh......so much mis-information

I do not think that the choice of one engine instead of another makes all this huge difference and I would not take this parameter too seriously to think that a turntable is better; I rather believe that everything in composing a turntable makes the difference better or worse than the competition.

There is no way the TT-71 aka QL-7  in N.A. a base model is coreless
but coming from raul its simply another off the cuff 
nonsensical remark.

Dear @banquo363 : Something is wrong somewhere ( maybe you are rigth. ) and maybe the 71 is not coreless. Here says that it’s along the 81:

""" TT-71 in clear bracketsMotor :FG detecting Coreless DC ServoDrive type :direct-driveServo type :Quartz Lock +/- Servo {Quartz Lock Servo}Speeds :33 1/3 & 45rpmPitch range :±6Hz from 440Hz {fixed}Speed change :electronic / electronic switches {electronic / touch sensors}Rise time :1s (33 1/3 rpm ; 120° turn) {1,4s ; 180° turn}0,025% (WRMS)Wow & flutter :63dB (IEC)S/N ratio :73dB (DIN-B ..."""

""" Precise FG detecting section consists of 180 slots FG yoke with a magnetic disc and an FG circuit board with equivalent 180 printed coils for excellent precision of rotation.
The servo is applied on both positive and negative areas for the TT-81, but only on positive for the TT-71. """


and in what halcro posted ( GT2000. ) says " JVC TT81 .... ""

About the GT2000 the motor is Yamaha the differences on specs are to high in between. I think that other than Denon, Technics and Pioneer other manufacturers can buy some parts from other sources as Micro Seiki than choosed for Technics/Panasonic motors but that does not says in the GT2000 that uses the 101 motor as @halcro think and what @best-groove posted is true a TT is not one characteristic design. In the other side what MS sourced to Yamaha was the platter overall design.
The fact that MS used in the RX5000 Panasonic motor certainly was not the main reason the MS units were " so desirable " because almost all owners of MS not even knew about. Same for Yamaha and other manufacturers. 

Anyway the JVC never competed not even with the 801 against the other named here top TT’s and that pátent is only bs and not as @halcro think that is the unique " all centuries invent " .

That he still sticked with the 101 even today says what he likes it: a lesser quality performance and not at the top as he think. Come on @halcro nothing wrong against you from my part but when even today you still listen music through those SAECs and FRs and the like how can I think of you in different way.

Anyway, each one of us are happy with what we own and at the end is what really matters.
Enough for me.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Audiophiles buy Lyra cartridges because Scan-Tech is the builder or because is Lyra and all what this means?

R.