Vintage DD turntables. Are we living dangerously?

Thanks Banquo,
I think my whole TT-101 is in amazing condition.
I counted up in the manual.....and there are 90 capacitors and my Tech replaced them all.......
He said that when he removed all the old solder joints.....there was so much black smoke in his workshop...that his wife thought the place was on fire :^)
He seems to have done a great job of re-building the deck...and he is young, talented and thorough....so it bodes well for the future?
Perhaps we aren't living dangerously...as long as there are good Techs around?

I didn't have the bearing re-lubed as the manual says it is sealed and never needs it. The platter turns so freely and is totally noiseless.....so if it ain't broke....?

Antonis' sprung bases appear to be 1" thick granite slabs with stainless steel and/or aluminium sheets laminated top and bottom in an attempt at creating Constrained Layer Damping.....however, I think he may have erred in his understanding of the principles?
Had he placed the aluminium sheet between two slabs of 1/2" granite with joint adhesive of viscoelastic consistency.....it may perform better.
Alternatively a material like plywood between the granite sheets seems a better choice as metal sheeting shares many of the same acoustic properties of stone?
The supports for his TT-81 and for the tonearm pods are solid stainless steel rods but the interesting choice appears to be that of the turntable supporting ring which I simply can't make out?
I'll have to ask him.....
I'm sure it sounds fabulous and he seems to confirm that at the first few listens....

10-13-11: Halcro:
"Doesn't it seem odd....if a coreless DC motor produces no cogging and sounds so 'fluid', relaxed and unfazed.....that a manufacturer would be foolish to even contemplate an alternative design?"

You look at the release of the models chronologically, then you realize all coreless motor models came out in latter days. Once they went coreless, they stayed coreless. This is the same trend in other brands such as Kenwood, Yamaha, Pioneer, Sony, Sansui, etc...

As far as I remember, the only two major brands stubbornly stayed with non-coreless motor was Denon who kept using their induction motor through out and Technics.

Pioneer's top of the line model was the P3 and latter P3a (linear motor). It was not coreless motor but it was too popular in the market place and too developed to change such flagship model. But in the models below that, they did switch to coreless motor. One example is the PL-50L, core motor, and the latter PL-50L II, coreless motor.

Looking at it historically, the trend in DD design is that by 1975 just about every table is quartz locked ( the "QL" in JVC models) and 1977 point on to early 80's, many Japanese manufacturers switched to coreless and stayed that way until CD took over the world.

One physical feature of a typical coreless motor is that they shape like a pancake usually flatter than their core siblings. It's because a coreless motor has no iron core to wrap around and they shape like a series of air coils in speaker crossover and the rotor is right on top of the coils.

I cannot scientifically confirm coreless motor is responsible for the fluidly smooth sound compare to other motor genres but from my own experience every DD table I heard using coreless motor has that sonic character. The first time I heard this smoothness was from a cheap Pioneer PL-300. It was outperforming its earlier more expensive siblings that got me curious about its motor structure. Playing records of violin solo gives a good idea of its smooth character.

03-26-14: Banquo363:
"There appears to be some disagreement regarding whether the tt 81 has a coreless motor or not. The vintage knob asserts that it does, but 'caligari' on this thread says he's positive that it does not."

Nowhere in the text of VintageKnobs.com mentions that the TT81 is a coreless motor. It says "the motor of both versions is a high torque 12-pole 24-slot DC-brushless." A brushless motor is NOT the same as a coreless motor.

After some research, the motors of TT71 and TT81 might be similar but they have different model numbers. TT71 uses M932A motor and TT81 uses M922A motor, according to their service manuals. The TT101 uses a M926 motor, by the way.

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When I used the word "stubbornly," I did not mean to discredit Denon and Technics in their confidence of the maturity of their designs and technology. If they felt their chosen motor type resulted in good sound quality then there's nothing wrong with not following the trend. It was just an observation and not a criticism. Personally, I felt Denon DD tables produce great sound. And I'm sure Technics followers would say the same. As the saying goes, many ways to skin a cat, right?

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hiho:

go to the 'specs' section of the page for the tt 81, here. For motor, it asserts: "FG detecting Coreless DC Servo"

That specs page is for TT-71, which the writer is assuming its motor is similar to the TT-81 and I can say the assertion that it uses a "coreless motor" is absolutely wrong because I owned several TT-71 units before and I have looked into the guts of all of them, all core motors. I even looked into the specs pages of TT-81 and QL-A7 (uses TT-71 motor) from their service manuals and none mentioned "coreless" motor.

Here's a simple proof. Just look at the first picture of the Amp8 repair page on a TT-71 under surgery and you can see the coils wrapped around the iron core. Axel, the owner and webmaster for vintageknobs.com might be an expert on Sony products but he's wrong on this JVC model.

While the TT-71 is quite decent sounding, better than most Technics, it is not quite up to the level of JVC's other DD tables with coreless motor. The TT-81 might be a different story though and based on Halcro's testimonial he seems to like it quite a bit.

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