Turntables with coreless motors

Discussion in 'Audio Hardware' started by mackat, Sep 18, 2021.

  1. mackat

    mackat Turntable hoar-...um, collector Thread Starter

    Location:
    San Diego, CA
    Many consider turntables from the early 80's, right before the advent of the CD, as the pinnacle of turntable design. Quite a few of these turntables had coreless motors, and some attribute their superiority at least partly to this. I would like to buy one of these at some point, as I still have not tried one.

    From the research I have done, the two main holdouts were Denon and Technics. The latter transitioned to coreless technology a few years ago, with the SL-1200MK7/GR/G, SL-1500C, and SP-10R. I would like to create a definitive list of turntables that use this motor technology, as I'm sure there are ones that I am not familiar with. Here are the ones that I know of:

    Kenwood : KP-990/KP-7010, KP-1100/KP-9010, KD-700D, KD-770

    Victor (JVC): TT-81 (I have read conflicting information, is this one actually coreless?), TT-101

    Yamaha: YP-D71, GT-750, GT-1000, GT-2000

    Pioneer: Exclusive P3, Exclusive P3a, Exclusive P10, PL-30II, PL-50II, PL-70II

    Technics: SL-1500C, SL-1200MK7, SL-1200GR, SL-1200G, SP-10R


    Are there any others that you can think of?

    Thanks,
    Ben
     
    Last edited: Sep 18, 2021
  2. Davey

    Davey NP: Maarja Nuut ~ Hinged

    Location:
    SF Bay Area, USA
    The coreless turntable motor was introduced on the Dual CS-701 in 1973 with the EDS-1000 motor. Most of the turntable manufacturers had coreless motors on at least some of their tables by the late 70s and early 80s, except for Denon and Technics. So that includes Sony and Luxman and Sansui and a bunch of others, Micro Seiki too, but they were concentrating mostly on their high end belt drives by that time, so I think only one or two of the DD models was updated to coreless, though they engineered many of those high end tables with coreless motors for others. And there are others today, Brinkmann, STST, VPI, PrimaryControl, Thrax Yatrus, and the rest.
     
    Last edited: Sep 18, 2021
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  3. Davey

    Davey NP: Maarja Nuut ~ Hinged

    Location:
    SF Bay Area, USA
    BTW, JVC did have a range of tables with coreless motors, and supplied motors to many others. The TT-81 was a cored motor, but the TT-101 was coreless. At some point in the very early 80s, their whole line of quartz lock DD tables used coreless motors, mostly derivatives of that TT-101 design.
     
    Last edited: Sep 18, 2021
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  4. Phil Thien

    Phil Thien Forum Resident

    Location:
    Milwaukee, WI
    What would one call the motor method where Technics mounted coils to a circuit board, and magnets to the bottom of the platter?

    That isn't technically coreless?

    My understanding is that coreless eliminates cogging? Any other turntable-related benefits?

    Do you have any coreless motor turntables in your arsenal?
     
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  5. JP

    JP Forum Resident

    Location:
    Brookfield, CT
    Technics only used coreless on their economical ‘tables back in the day.
     
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  6. Davey

    Davey NP: Maarja Nuut ~ Hinged

    Location:
    SF Bay Area, USA
    Yes, those are coreless motors, that is one of the common construction methods. Coils are wound and then mounted to circuit board as the stator. The platter becomes the rotor with magnets mounted to it. It also describes the newer Technics motor in their lower cost models (MK7/1500/1200GR).
    They have obvious benefits in package integration and form factor, but those are more production and/or styling benefits, and as @JP mentioned above, Technics did move to that pancake form-factor for the motors in their cheaper low torque DD tables in the 80s, but stayed with the high torque cored designs in their top tables, including the top linear trackers like the SL-10.
    Not that I use currently. I'm mostly belt-driven and have a couple older Micro Seiki DD tables that both use Matsushita motors, the DD-10 uses the same motor as the SP-10 and the D-40 uses the same cored motor as the Kenwood KD-500 and probably some other decks of that period (1978). I've had a Yamaha GT-1000, but it's kind of on permanent loan, and I don't really like that turntable style, too thick and heavy. It was a good sounding table, though. I have a Dual/Pabst EDS-1000 motor from a Dual CS 701 that I was planning to put in a custom plinth, but those are old plans and I will probably just sell it sometime, I'm pretty satisfied now with the Micro BL-91 and the DD-40 as my main tables.
     
    Last edited: Sep 19, 2021
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  7. JP

    JP Forum Resident

    Location:
    Brookfield, CT
    I thought that motor was actually Matsushita, or is that a different unit in the 500 series?
     
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  8. Davey

    Davey NP: Maarja Nuut ~ Hinged

    Location:
    SF Bay Area, USA
    Yes, that's what I said, same motor that's in my Micro Seiki DD-40. It's a good motor, has all the control electronics inside, so a little more difficult to service if you want to lube and replace the capacitors, but comes apart pretty easily. I've also added some platter mass to my DD-40 with a 1/2" aluminum mat glued to the stock platter, but was sill a smooth running motor in stock form.
     
    Last edited: Sep 19, 2021
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  9. ssmith3046

    ssmith3046 Forum Resident

    Location:
    Arizona desert
    Love my Dual 701.
     
  10. JP

    JP Forum Resident

    Location:
    Brookfield, CT
    Ah missed that at the start of the sentence.
     
  11. TheVinylAddict

    TheVinylAddict ___The Enforcer___

    Nice list in your intro. Looks like the list I provided in the Vintage Japanese TT thread!

    I own four of those - the PL-70Lii, KP-9010, GT-2000L (note the L, walnut not black) and the 1200G

    Nice tables when you find good condition, working examples.
     
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  12. Oelewapper

    Oelewapper Plays vinyl instead of installing it on the floor.

    The Sony PS-X50:
    [​IMG]
     
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  13. mackat

    mackat Turntable hoar-...um, collector Thread Starter

    Location:
    San Diego, CA
    Thanks for all the info, guys! How could I forget the original coreless Dual 701? I also was wondering about those lower end Technics, as I had an SL-D202 that I ended up giving to some friends.

    I happen to have a Kenwood KD-500 that needs a tonearm, as well as a Micro DD-7 (DD-40) that has some cosmetic damage from shipping and also rotates at a very high speed. I've been procrastinating both on buying a tonearm for the KD-500 (got a Grace G-545F, but the weird cueing lever hit the plinth) and getting the DD-7 restored. Neither are coreless, but I figured I'd mention them since you did :D

    Thank you! I may have found some info in one of your posts, sorry for not giving credit if that's the case. That is a nice collection!

    I currently have a PL-70, the prior model which isn't coreless. The two I'd really like to try are the 1200G and KP-9010. Of course, the latter can be had for quite a bit less than the former.
     
  14. TheVinylAddict

    TheVinylAddict ___The Enforcer___

    It's all good, that's what it's there for, no credit required! I am happy it was useful if so.

    KP-9010 - hard to find in nice condition, although the x-brace chassis makes it a very solid platform, they saved $$ on the plinth, cover -- it's a little cheaper on the exterior, and the black gloss doesn't age / wear well. This table is a real sleeper though, it's 90Db S/N rating is the highest I've seen, it's a very, very solid table.
     
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  15. JP

    JP Forum Resident

    Location:
    Brookfield, CT
    That's the new math though, which puts it in line with its peers.
     
  16. TheVinylAddict

    TheVinylAddict ___The Enforcer___

    LOL, yeah, the 1987 version of new math though, when the KP-9010 was made....
     
  17. JP

    JP Forum Resident

    Location:
    Brookfield, CT
    It was some time in the early 80's when the EIAJ revised the rumble weighting. All of a sudden 'table rumble specs were nearly 20dB better.
     
  18. TheVinylAddict

    TheVinylAddict ___The Enforcer___

    Yes, aware of that.... but if you're implying the KP-9010 is a 70Db S/N, then this is one case where it wasn't in effect. Are you familiar with this particular table?

    All sorts of stuff in audio gets "overrated"..... fact of life. But due to the x-brace chassis, the KP-9010 should rate high and I believe it does, many run them naked (without plinth) due to the stability of the chassis.
     
  19. JP

    JP Forum Resident

    Location:
    Brookfield, CT
    Yes I'm familiar with it. The chassis isn't going to materially affect bearing rumble. All the better tables measured with the revised standard measure in the same ballpark.
     
  20. harby

    harby Forum Resident

    Location:
    Portland, OR, USA
    Most any Technics that doesn't use the 3-phase SL1200's stator (see my list here) will instead be using the newer two-phase 8 coil coreless PCB motor. The 21st century 1500C/1200mk7 look almost identical in construction but are 3-phase 9 coil.

    See the one used in that SL-D202:

    Field generation coil and Hall-effect sensors pictured on this side:
    [​IMG]
    Coils peeking out from underneath:
    [​IMG]

    Direct-drive Sony, like PS-LX410 or here PS-LX3, seem content with 2-phase 4-coil:
    [​IMG]
     
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  21. norliss

    norliss Forum Resident

    Location:
    Cardiff, Wales
    I've got a KP-1100 which is basically the same as the KP-9010 made 1986-89 with the latter being made from 1989 to ? As far as I can tell they're both more or less identical to the KD-990 sold in the west albeit the latter lacks the extra chrome "lip" around the platter?

    Regardless, they're stellar tables.
     
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  22. TheVinylAddict

    TheVinylAddict ___The Enforcer___

    I also have a KP-1100. See here Looking for a vintage (japanese) direct drive for the deal / find I got on mine. (scroll down for pics).

    Yes, the 1100 is identical from a motor / tonearm etc standpoint, but they put a little more meat in the plinth on the 9010 I believe because it weighs a couple pounds more.

    I have my 1100 running now, I can't find any difference to the 9010 from an appearance, operational or the way it sounds.... they are virtually identical. VintageKnob also states this, that they're identical.
     
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  23. norliss

    norliss Forum Resident

    Location:
    Cardiff, Wales
    You're the legend that got a NOS unit. What a find! :righton:
     
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  24. TheVinylAddict

    TheVinylAddict ___The Enforcer___

    Yeah, and believe it or not an Ebay find --- sat there for weeks from a Japanese seller who sells tons of audio gear. I finally took the chance and was as you saw and was very surprised and pleased.

    That's why you can't discount any avenue when looking - many negatively stereotype certain places to buy (like Ebay) - but then you'd never have a chance to find something like this if you do.
     
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