The Technics SL-1200 GAE/G/GR general questions thread

Discussion in 'Audio Hardware' started by Halloween_Jack, Aug 1, 2018.

  1. snorker

    snorker Big Daddy

    Interesting...in my case it seemed to improve the bass performance a bit, making it a bit more taut. However, I haven't tried it without a weight in a while. Maybe I'll experiment a bit to see if I can still tell the difference.
     
  2. Drewan77

    Drewan77 Forum Resident

    Location:
    UK/USA
    In my system (DEQX active 5 way, Open Baffle) the effect was very noticeable - the best way to describe it was 'more laid back'. Bass actually became slower and less defined whereas it's always very deep but fast, tight & layered (no weight, no clamp). On the RP10 clone, a weight adds bass impact, almost the opposite to my Technics!

    Different systems, different ears, different preferences I suppose....
     
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  3. snorker

    snorker Big Daddy

    That certainly seems off, although the manual does warn (on P.24) "Do not press [START-STOP] when the turntable is removed." Anybody know why that would be a problem?
     
  4. TarnishedEars

    TarnishedEars Forum Resident

    Location:
    The Seattle area
    I think that the reason that this might be a problem is because the motor almost certainly uses hall-effect sensors as part of its servo to keep the platter speed constant. And without the magnet underneath the platter to receive its feedback from, the circuit can't operate as intended. Perhaps this even has the potential of causing damage to the motor circuit since the turntable would think that the platter is not spinning, and so it might be electrically trying to spin the non-existent platter as fast as it possibly can.
     
  5. TarnishedEars

    TarnishedEars Forum Resident

    Location:
    The Seattle area
    Ok, a new question for 1200G owners: Can some of you please report back as to how much the G platter rings when it is tapped-upon by a fingernail? It is completely dead (producing only a thud sound), or dues it lightly ring at all?

    The reason that I ask is that while I can tell that my 1200GR platter is WAY more dead than the original, it still rings very lightly for a second or two whenever it is directly tapped upon.
     
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  6. Gabe Walters

    Gabe Walters Forum Resident

    Grand Class Direct Drive Turntable System SL-1200GR Hi-Fi Audio | Technics US

    Scroll down for the damping characteristics graph. There’s also one for the G on its product page.
     
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  7. Erocka2000

    Erocka2000 Forum Resident

    Location:
    Brooklyn, NY, USA
    My 1200G platter is completely dead.
     
  8. TarnishedEars

    TarnishedEars Forum Resident

    Location:
    The Seattle area
    I've seen the graph. It looks impressively better than does the Mk5 graphs. But it still doesn't fully communicate to me whether one can still hear a very slight ring when tapping on the platter or not the way that hearing a very distinct "thunk" while tapping on a dead platter does.
     
  9. Gabe Walters

    Gabe Walters Forum Resident

    True, and I just noticed that the x-axis isn’t labeled.
     
  10. Davey

    Davey NP: Michael A. Muller ~ Mirror Music (2024 LP)

    Location:
    SF Bay Area, USA
    The G uses an optical encoder on the bottom of the motor to generate the speed control pulses, not the platter. The GR uses a different system.
     
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  11. snorker

    snorker Big Daddy

    Like @Erocka2000, the platter on my SL-1200G does not ring at all when tapped. Dull thud.
     
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  12. recstar24

    recstar24 Senior Member

    Location:
    Glen Ellyn, IL
    Check the manual, but I believe it states it can handle a weight up to 1 kg (don’t quote me, it’s in the manual I swear)
     
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  13. RPM

    RPM Forum Resident

    Location:
    Easter Island
    G or GR manual?
    G has no magnet attached under the platter.
     
  14. snorker

    snorker Big Daddy

    SL-1200G.
     
  15. RPM

    RPM Forum Resident

    Location:
    Easter Island
    Even MK2 manual says that, IIRC, and a popular belief is that you may fry the motor if you do that. But G has different concept and I'd also like to know why it shouldn't be started with no platter on. Thinking it has something to do with the platter weight applied on the rotor and is not as risky as on MK2 (no fry gonna happen, but what will?).
     
  16. keiron99

    keiron99 Forum Resident

    Location:
    Stockport, UK
    My replacement G arrives today. Now in wondering whether or not to test it without the platter in place!

    The odd thing is that with it in place, speed was spot on. But with it off, it was clearly erratic.
     
  17. punkmusick

    punkmusick Amateur drummer

    Location:
    Brazil
    The motor is designed to rotate with the platter. I would never even try to run mine without it. I see no reason for this "test" as it will tell you nothing.
     
  18. snorker

    snorker Big Daddy

    I wouldn't do that. As noted in my post above, the manual explicitly warns against running the motor without the platter installed.
     
  19. TarnishedEars

    TarnishedEars Forum Resident

    Location:
    The Seattle area
    I can also state that the GR manual also explicitly warns never to unscrew the motor from the platter at all. This is because unscrewing these pieces will likely throw the platter off-balance when you re-assemble the pieces.
     
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  20. keiron99

    keiron99 Forum Resident

    Location:
    Stockport, UK
    Just checking we are talking about the same thing. I'm talking about simply running without the platter. I'm not talking about unscrewing the motor.
    I'm not arguing with the advice in the instructions...but I am curious as to why running it without the platter could cause harm or as I have found cause the motor to run erratically.
     
  21. Davey

    Davey NP: Michael A. Muller ~ Mirror Music (2024 LP)

    Location:
    SF Bay Area, USA
    Just a total guess, but the motor control loop is designed for the platter mass/inertia, and without it would be supplying way too much torque, and maybe at the wrong times.
     
  22. Halloween_Jack

    Halloween_Jack Senior Member Thread Starter

    Location:
    Hampshire, UK
    Why run the risk?...
     
  23. TarnishedEars

    TarnishedEars Forum Resident

    Location:
    The Seattle area
    This is just a reasonably educated guess, but here goes:

    The platter assembly (which includes the motor), all runs inside of a feedback loop. This feedback loop is how the system regulates its speed to stay nearly perfectly at speed all the time. When the platter is removed, an optical encoder which is mounted on the inside of the platter is also removed. This encoder is a critical portion of the feedback mechanism. And if it is not sending a valid signal back to the motor, the motors literally has no idea if it is going too fast or too slowly. As a result, at best it will hunt around for the correct speed, and the speed will be extremely eratic. At worst, this might cause the system to over-voltage the motor, or to send it large current pulses, in an attempt to get it back up to speed.

    Either way, the system is simply not designed to be run like this, and you risk damaging it by doing so. This is not like a typical belt-drive turntable where there is no feedback mechanism between the motor and the platter. In the case of a typical belt drive TT, the motor is going to run at its own speed, regardless of what speed the platter is running at. Direct Drive TTs simply do not work this way.
     
    Last edited: Aug 14, 2018
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  24. Drewan77

    Drewan77 Forum Resident

    Location:
    UK/USA
    Sorry but to me, this latest topic seems to be getting a bit out of hand & I really don't believe 'tests' are necessary on the replacement turntable.

    Yes the first 1200G clearly had some issues but let's not assume the second is going to be similar. If it was me, I would just play it as the manufacturer intended & no doubt it will be great (as is my own SL1200G, I suspect purchased from the same retailer - my UK home is not far from Manchester).
     
  25. MusicNBeer

    MusicNBeer Forum Resident

    Location:
    Florida
    As far as the platter ringing goes, doesn't the rubber mat isolate sufficiently anyway? I'm assuming certain frequencies on the vinyl triggering the resonance of not damped with the mat.
     

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