Vintage DD turntables. Are we living dangerously?

Regards. Hiho is correct. For a description of JVC technology in the above TTs:

http://www.vinylengine.com/library/jvc/turntable-technology.shtml

A later catalogue states ALL TTs are equipped with coreless motors.

Peace,

Regards, Hiho: A TT71? Guilty. Picked up for little more than pocket change several years ago just to fiddle around with. A hard maple plinth & EPA-250 tonearm. Swapped around some mats (the OEM mat is terrible) & ended up with a Boston Audio Mat2. The basket shrouding the electronics rings, so strapped a couple of bungee cords around it. Cyro'd bungees are in short supply, used what was available. Bluejeans brand entry-level low capacitance cables & some Isonoe feet at the corners. Pulled the Pio. Exclusive PL-70L 11 & then sat for a semi-serious listen.

The little 71 lacks the ability to capture micro detail but is engaging and involving, I like your reference to flavors and colors :). You mentioned Raul; the gentleman also sampled the TT71 and actually praised it, I believe he used it "nude".

No Timeline available but out of curiosity the 71 was timed for eighteen minutes. From a cold start it immediately advanced a nominal four degrees and then remained spot on for the remainder. It's been a while since researching but IIRC the 71 lacks the reverse eddy current braking both the 81 and 101 implement in regulating overshoot incurred when correcting for speed. Other than the coreless motor, the only other difference for the 81/101 is the readout for the 101 is digital, the 81 is equipped with a strobe.

Just an enthusiast, I find critical listening a distraction. I've not read a negative comment concerning either the TT81 or 101, JVC seems to have gotten the series right. Of this I am certain, in spite of, or perhaps because of, the resonant character of the modest 71 it is somehow a captivating performer. Some day I'll return to the PL-70L 11 with it's "stable hanging rotor" drive and exquisitely engineered PA-70 tonearm and then experience a revelation as to what I've been missing.

In reference to Halcro's OP, among others I've a Tech. SP-15 which I expect to someday start spinning like a gyroscope and a Denon DP-60L (a carnival of resonances) with it's fragile magnetic tape attached to the platter.

Pardon the lack of references, corrections to any of the above are welcome.

Peace,

Regards Lewm:

Retrieved from JVC literature:

Both the TT81 and 101 utilize a servo system operating in both positive and negative directions. A disc with either (dependent on model) 180 or 90 slits is opposed to a circuit board with the corresponding number of printed-coil elements. A phase comparator circuit reconciles the signal from a quartz frequency generator with the one built into the motor.

If my math is correct, for the TT101 at 33.3 RPM, speed is sampled and corrected every 0.003 seconds. This second "negative" servo system is absent in the TT71.

Speed deviation for the 101 & 81 is given as 0.002%
Drift stated as 0.00004%/hr.for the 101 & 81. 0.0002%/hr. for the 71.

From this source:

http://audio-database.com/PIONEER-EXCLUSIVE/player/p3-e.html

"Linear torque scheme of a slotless and a coreless structure by Quartz PLL is adopted as a phone motor and a bearing structure. Furthermore, by the conventional measuring method, the impossible rotation performance of 0.001% of less (---) rotation unevenness 0.003% (WRMS, the FG method) a rotational frequency precision is realized."

http://audio-database.com/PIONEER-EXCLUSIVE/player/p10-e.html

"Rotation unevenness, 0.007% (WRMS, the FG method) 0.015% (WRMS, the Japanese-Industrial-Standard record method)."

http://audio-database.com/PIONEER-EXCLUSIVE/player/pl-70lii-e.html

"Rotational frequency deflection 0.002% or less. Time drift : 0.00008%/h."

Again relating to the OP (and I'd not wish to put it to the test) by all references Pioneer is committed to service components bearing the "eXclusive" badge.

Apparently my "IIRC" function is somewhat out of phase. Apologies were offered in advance. In view of maintaining accurate information your comments are entirely appropriate.

Peace,

Regards, Lewm: Please re-read. Prominent mention of servo systems incorporated in the discussed JVC TTs. Also an acknowledgment that a correction was made to a hurried and unsupported comment. Would you kindly put your dog back under the porch?

Hiho: It's good to see that you actually viewed the Pio. links. The mention of a coreless drive in each of those links relating to the Exclusive series TTs should answer an earlier question. Their inclusion was intentional.

As to the specs given, it would seem likely that both manufacturers measured at least ONE unit that spec'ed as quoted. It would be interesting if anyone could provide contradictory figures.

Ya'll carry on &

Peace.

Regards, Halcro: Congratulations on the TT-71. The deck is capable of demonstrating the qualities of alternate mats, have fun! (Nice cartridge / stylus too).

Peace,

Regards. Stereoneedles (dot com) still offers the original ATN155LC. Another alternative from the same vendor would be the ATN140LC, a nude LC stylus on a tapered alloy cantilever. A slightly warmer performer.

As Halcro (hi, Henry!) mentioned, the 155LC is an excellent upgrade stylus for the TK-5Ea, detailed response while avoiding distracting brightness.

Peace,