Vintage DD turntables. Are we living dangerously?

Thanks, Downunder. I hardly think that the speed and precision of the P3 is due to its fast start. One is not listening at the start. Yet there does seem to be a consensus that a sense of "speed" or pace or whatever like that is superior for most direct drives vs most belt drives. For one thing, this may have to do with belt creep or belt stretch; no matter how sophisticated is the motor drive, it's work is applied to the platter via that belt.

Hiho, Great photos of the LO7D motor coils but the photos at the website only get one to an index page and for me the URL goes dead at that point. Not to worry. I am wondering whether the guy you referenced is correct when he implied that the assymetric placement of the coils on the original LO7D motor and on the Bardo motor would result in aberrant drive from the motor. I think the field created by the coils would average itself out. (I also think there would be a limit to the odd spacing where once reached the field would no longer be able to average itself out and would result in a dead spot on each rotation.) But this is just idle speculation and curiosity.

He said or inferred that the Dual CS5000 would have an EDS coreless motor. But based on what I read at the Dual history website, that may not be the case. Just what models of Dual DO in fact have the EDS motor. I think their idler drive tts, like the 1019, have induction motors (a la my Lenco).

Lewm, I was hoping you would click on the "Kenwood repairs (including three L-07D !!) prompt and click on any one of the L-07D buttons. (Obviously I am a finger clicking happy internet search fiend!) Check out all those dozens of hi-rez images of repair parts. Amazing clarity.

Lewm: "I think the field created by the coils would average itself out. (I also think there would be a limit to the odd spacing where once reached the field would no longer be able to average itself out and would result in a dead spot on each rotation.)"

He did mention that the Bardo works in a "soft drive" approach and, perhaps the L-07D might also work in similar way:

Wjsamx: "In regards to the Brinkmann motor, I can't understand the reason for the odd placement of the coils. One would think there is a dead spot of power in its rotation which is why I believe its concept is to push and brake. The motor seems by design to only pulse power to the rotation as needed. Once the heavy platter is at speed, the energy within its mass is creating the needed centrifugal force for rotation. The tach feedback will sense speed deviation and only micro-pulse the "motor" as necessary to keep the platter steady at speed, like cruise control. Judging by the size of the motor, it's not meant to "direct drive", it is just too small and weak. It's really a "soft drive" system. Weak micro-pulses of "magnetic" power to the platter would certainly not create a large impact on such a heavy platter, thus eliminating any cogging effect."

It reminds me of the belt-drive school of using weak motor to nudge the heavy platter to keep it up to speed and let inertia and flywheel effect take over. After all, Brinkmann is a mostly famous for the belt-drive turntables so they might be approaching DD with a BD mentality. Hey, if it gets the job done, I have no problem with that.

If it sounds good to you then that's what matters. I have some JVC motor with asymmetrical coil layout and they sounds very smooth to me. But I have to say the Dual 701 motor has a harmonic richness I don't hear from most DD tables and whether that has to do with its symmetrical coil arrangement or not, I have no idea.

Lewm: "He said or inferred that the Dual CS5000 would have an EDS coreless motor. But based on what I read at the Dual history website, that may not be the case. Just what models of Dual DO in fact have the EDS motor."

On the Dual Reference site, it does say the motor is "EDS 5000 System." It's a belt drive turntable so I don't know if the motor is usable for idler drive purpose or not. The most famous EDS motors are obviously in their two DD tables, 701 and 721.

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Yes, the direct-drive school does seem to have two camps, high torque motor/light platter vs low torque motor/heavy platter. And yes I think the LO7D is more in the latter camp, certainly compared to Technics stuff. There is an analogy in belt drive turntables too. Notts and Walker (to name two of many) favor weak motor/gigantic platter. SME and (argghh I can't remember the name, begins with an "A") would be in the light platter/powerful motor school.

The only guy I know for sure who would understand this stuff and could explain it to us is Mark Kelly, but he is preoccupied with other things at the mo'.

Avid. That's the name I was trying to think of. Nice stuff. Light-ish platters/high torque motors.

Using a stethescope (is that sick or what?) I can hear a hum that sounds like the transformer to me: it only sounds when the power is on whether or not the platter is spinning. It makes me think about pulling the power supply out of the tt and moving it into a separate box. Has anyone done this? If there aren't many different feeds at perhaps different voltages then I would think it could be done without spending a fortune. Am I dreaming?