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Linn LP12 power supply advice

Discussion in 'audio' started by Ducatiist, Oct 15, 2020.

  1. mickhick1

    mickhick1 pfm Member

    I believe the speed control is done by varying the frequency, but don't quote me. It has PID control and speed readout and wow calculation display. On my turntable it is controlling the speed to +/- 0.002 rpm and shows an average wow figure of +/- 0.002.
    To me the greatest improvement has been the pitch stability and reduction in background noise resulting in a very musical listening experience.
     
  2. chartz

    chartz pfm Member

    But then no belt drive is so precise because of belt elasticity and platter inertia.
    Simple electromechanics.
    Better pitch stability is an illusion in this case.
    You’d need a very light platter to achieve that. Exactly why B&O chose to use thin alu platters!
    You can’t have speed control and inertia.

    This kind of speed monitoring loop only really makes sense with direct drives.

    What you want with an AC motor is to feed it with a perfect sine wave, but there’s little else to it.
     
    Mr Pig likes this.
  3. sktn77a

    sktn77a pfm Member

    I guess the motivating theory is that inertia damps out high frequency speed variations (high frequency being arguable but I in this case, probably in the 15-120Hz range). Passive mechanical speed control vs active electronic speed control.
     
  4. martin dawson

    martin dawson pfm Member

    I had a Lingo 1 when they first came out in the early ‘90’s when I had the Ittok on the LP 12. Then in 2004 moved onto an Aro, I just found something lacking. Sold the Lingo 1 and bought a Armeggedon such a synergy with the Aro, I don’t play 45’s.

    Regards,

    Martin
     
  5. chartz

    chartz pfm Member

    Then you need to know the truth: the Armageddon box contains nothing, just a transformer that lowers mains voltage. There is zero regulation effect, what you get is the exact same sine wave.

    Garbage in, garbage out :D

    Many years before Naim sold it, and got away with it, I used that technique I learnt at school to lessen my Thorens Swiss AC motor vibrations.

    The Lingo was a proper, well designed low distorsion amplifier. It was expensive but at least you didn’t get to buy an empty box!
     
    Mr Pig likes this.
  6. DuncanF

    DuncanF pfm Member

    The Hercules/Valhalla will let you set voltage or phase, not both. I've just completed an offboard Valhalla into Thorens TD160 project and played with the phase cap to find the sweet spot for the Thorens motor. When you adjust the output voltage the phase angle will vary. And this will be affected by the impedance of the motor under load. So you have to choose which is more important: voltage or angle. I suspect that adjusting for exactly 90 degrees will give the smoothest, quietest running, regardless of voltage.

    For the Valhalla in a Linn I guess that the phase cap of 0.22uF adjusted for 85V primary was a good default setting for Linn to achieve 90 degrees with their motor. Measuring that for dealers when the Valhalla came out would have been tricky, so a sensible "set to 85V" default was a good approach. These days any modern oscilloscope will have that capability. So blindly lowering the voltage for "quieter running" without measuring its affect on the phase angle is pointless.

    FWIW with the Thorens motor 0.20uF allowed me to get 90 degrees at 120V. Smaller capacitors (0.15uF) got me 90 degrees but at Linn level voltage (85) which the Thorens motor didn't like. I'll get hold of a 0.18uF and see where that gets me.
     
  7. Mr Pig

    Mr Pig ^'- -'^

    What are you talking about? Yes they did. Linn were selling the adapter at the time when the Valhalla was the only PSU available and I don't remember hearing about any problems. Never had any issues with mine. It's a slightly larger pulley, how can it not work?
     
  8. chartz

    chartz pfm Member

    A 0.15 µF at 85 V works perfectly for me. There are no vibrations at all and the motor starts very happily.

    [​IMG]
     
  9. DuncanF

    DuncanF pfm Member

    Which Thorens is yours? I have a TD160 Super. I've seen two flavours of on-board PSU in 160s. The one in my Super used a 0.15uF cap with a 10K dropper and a DPDT switch. In the Thorens service manual a different circuit layout is shown using a 0.33uF cap with a 5K6 dropper and an SPDT switch on line only, with a spark suppressor across it. In mine the direct phase is blue, whereas in the manual, the direct phase is red. Which suggests that not all TD160 family decks have the same motor.

    Edit to add: ah, just noticed in your picture the red/blue reversed, like mine. So a 160 Super? Interesting you could get away with 0.15uF. What voltage di you adjust it for, and what phase angle did you get at that voltage?
     
  10. chartz

    chartz pfm Member

    Same as yours, but not super. ;) 10k resistor and 0.15 µF cap.
    Linn default voltage and 90 degrees.
     
  11. suzywong

    suzywong Wot, no electrons?

    Yep, we had bought the adaptor pulley in the days before Valhalla, and it worked fine, but after we'd had the Valhalla fitted it just wouldn't work. It would try to start up, there would be a bit of moaning & groaning, but even if I gave the platter a "push start", it just would not spin up. at all. Never understood why, and should really have taken it back to the dealer in Reading, but never got around to it and we only had a few 45s anyway.

    Fast forward 20 (-ish) years and I replaced the Valhalla with a s/h Lingo 1. Issue gone away.
     
  12. Mr Pig

    Mr Pig ^'- -'^

    So, you had a problem. Therefor, none of them worked??
     
    judge_dreadful likes this.
  13. suzywong

    suzywong Wot, no electrons?

    No, I don't remember saying that "none of them worked"....the one in my deck didin't.
     
    Nytechy likes this.
  14. Mr Pig

    Mr Pig ^'- -'^

    You are right, I apologize. I read what you said as implying that the pulley didn't work, period, but that was obviously a wrong interpretation.

    Can't think why it wouldn't work though. You had to get the platter up to speed by hand but I always did that with the LP12 anyway. I never just switched it on and let it fight.
     
    Nytechy likes this.
  15. suzywong

    suzywong Wot, no electrons?

    No worries. I also tried the "spin it up by hand" method as well, but it would just die on me... and I always used the belt that had come with the adaptor.

    in the end other stuff intervened (CDs, children, cats etc) and for over a decade the Sondek was unused. So the problem remained "unfixed" until I got the Lingo, and started buying those "12" of plastic with a hole in the middle" thingies again.
     
  16. deebster

    deebster Half Man Half Biscuit

    When I used the 45 rpm adaptor it would take an unnervingly hard push down to fully engage on the motor spindle, otherwise the belt would be sitting too low on the adaptor (where the side is at an angle) and cause speed issues.

    Then when getting the Hercules fitted by Peter Swain he recommended giving the platter a helping hand at startup, which has now become the norm for me.
     
  17. Big Tabs

    Big Tabs pants up, knee down

    No use to anyone I think, but may be of interest.

    I have a Inspire/Heed offboard psu that I have used for years on a Heybrook TT2s - I think Robert offers the same(similar) with a DC motor for the LP12 . Inspire hifi, somewhere near Chesterfield.


    My PSU has a button on the front to switch twixt 33 and 45, power switch at the back. Just a black block, orange led in the front that switches to green if 45rpm is selected.

    2nd edit: I think it is a Heed Orbit
     
    guydarryl likes this.
  18. Mr Pig

    Mr Pig ^'- -'^

    Mine was the same but it loosened up over the years. Never did like it though, a fairly crappy solution. I gave mine away. With the exception of 12'' singles, 45s sound rubbish anyway. I keep mine in the shed and occasionally spin them on a vintage Planar3.
     
  19. Charlie_1

    Charlie_1 pfm Member

    Would have thought the Lingo was primarily developed with an Ekos-fitted deck, but maybe you would have felt the same way about that too.

    The first 80s NAPSA was developed using an Ittok with a modified collar from what I gather.

    Hoping to try a Geddon soon (with near empty box ) as I've never heard one. Unfortunately I don't have an Aro to partner it with.
     
  20. wylton

    wylton Naim and Mana member

    I have a Lingo 1 and a Norton AirPower and I'm seriously thinking of running them side-by-side; the Lingo for 45s and the Norton for LPs, they’re pin-to-pin compatible, so it’s only the hassle of swapping leads, unless I can make a simple switch-box.
     

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