Rega Pulley Wobble

Discussion in 'Audio Hardware' started by RI79, Jun 23, 2022.

  1. RI79

    RI79 Member Thread Starter

    Location:
    Rhode Island
    This year I resurrected my Rega P5 from storage. I’ve made a few upgrades, including a Clearaudio Maestro V2 Ebony cartridge and GrooveTracer Reference Subplatter; Delrin platter; and record weight. At this point, I think it sounds really great. However, I noticed that the pulley wobbles significantly. I’ve tested the speed using an iPhone app and strobe disc. Using the Neo PSU MK2, the speed is extremely consistent after adjustment. Aside from the ugly aesthetics of the wobble (not that I can see it when using the turntable), is there any reason why I should replace the pulley — get it spinning perfectly?

    [​IMG]
     
    Randoms likes this.
  2. jonwoody

    jonwoody Tragically Unhip

    Location:
    Washington DC
    Your video didn't post you should try embedding it as media. Scratch that sorry I just tried it won't work.

    imgur.com
     
  3. Glmoneydawg

    Glmoneydawg Forum Resident

    Location:
    Ontario Canada
    Opens in another tab ok
     
    jonwoody likes this.
  4. bluesaddict

    bluesaddict High Tech Welder

    Location:
    Loveland, Colorado
    Can you hear anything while playing an album?
     
  5. Glmoneydawg

    Glmoneydawg Forum Resident

    Location:
    Ontario Canada
    If your speed is ok it may not be that severe at the drive surface for the belt.....having said that,pulley is probably inexpensive and worth the peace of mind :)
     
    bluesaddict and jonwoody like this.
  6. Davey

    Davey NP: Principe Valiente ~ Barricades (2022)

    Location:
    SF Bay Area, USA
    Yea, that looks pretty bad, will definitely add a lot of wow and flutter. Is the motor loose, or the motor shaft bent, or pulley loose on shaft?
     
  7. RI79

    RI79 Member Thread Starter

    Location:
    Rhode Island
    I hear you, but I wonder if I’d be able to replace the pulley easily. There doesn’t appear to be a hole at the top of the pulley. It doesn’t look like those in any of the instructional videos I’ve seen online. My understanding is that I’d need to insert acetone down the top shaft to dissolve the glue that hold the pulley in place.
    [​IMG]
     
    Last edited: Jun 23, 2022
  8. RI79

    RI79 Member Thread Starter

    Location:
    Rhode Island
    The pulley can be depressed toward the plinth and springs back into place. Is that normal? If it’s bent, I can’t see it. It isn’t loose on the shaft.
     
  9. Glmoneydawg

    Glmoneydawg Forum Resident

    Location:
    Ontario Canada
    Shaft looks straight to me....don't push it down you're pushing against the bottom bearing in the motor...not cool.
     
  10. RI79

    RI79 Member Thread Starter

    Location:
    Rhode Island
    Thanks. I’ll not push it down again! If my measurements indicate that the speed is consistent, I’m guessing wow and flutter isn’t an issue. Is that accurate?
     
  11. Glmoneydawg

    Glmoneydawg Forum Resident

    Location:
    Ontario Canada
    Depends whats going on there....if the outer pulley rim is just cut off center then not a big deal....if the inner surface that the belt rides on is off center then i would definately replace it. Thats a nice turntable and a new pulley is only about 30 bucks.
     
    RI79 likes this.
  12. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    You’ve made a video of the motor pulley without the stabilizing weight of the platter in place. The motor, pulley, belt and subplatter are stabilized by the balancing weight of the platter, and that’s why you don’t have a speed problem.

    Pull the platter off almost any belt-drive turntable and then turn on the motor. You’ll find similar issues… except they’re not really issues because most turntable makers design and build their turntables to be used with a platter. Many turntable makers actually advertise that their platters help stabilize and even out tiny speed variations.
     
    RI79 and KT88 like this.
  13. Glmoneydawg

    Glmoneydawg Forum Resident

    Location:
    Ontario Canada
    Yep.... inertia is our friend here :)
     
    RI79 likes this.
  14. RI79

    RI79 Member Thread Starter

    Location:
    Rhode Island
    Thanks. The GrooveTracer subplatter and platter were such a nice upgrade. I was surprised that I could hear such an improvement in sound!
     
    SCM, Agitater and Glmoneydawg like this.
  15. Randoms

    Randoms Aerie Faerie Nonsense

    Location:
    UK
    I don't know the Rega tolerances, but to give you an idea, Linn quote a pulley concentric to 0.01mm on the LP12 and I gave never seen a Rega do that before.

    A new motor and Rega Reference EBLT Drive Belt (if you're not using one) should give a big improvement.
     
    RI79 likes this.
  16. Davey

    Davey NP: Principe Valiente ~ Barricades (2022)

    Location:
    SF Bay Area, USA
    I think his motor is the type that is attached to a phenolic plate, which is then secured to the wood plinth with the bolts and washers, as you can see in the picture. I think they use thin adhesive backed foam to attach the motor to that phenolic plate, and if so, it could be degraded allowing the motor to flop around, but I'm no Rega expert. The camera is moving so I can't tell how stable the motor shaft is, and whether it is moving back and forth with the pulley, but regardless, something is wrong and should be fixed, at least that is the way I see it, I've never seen a belt drive motor pulley wobbling anything like that before :)
     
    patient_ot likes this.
  17. plastico

    plastico Forum Resident

    Location:
    ontario canada
    I replaced my original pulley with a couple of after market pulleys. This was with the old motor and the new 24v motor. And the pulley always ran true without any loading. If your motor is secure its either the pulley is loose and not sitting true on the shaft or the motor shaft is bent.
    Cheers, Doug
     
    RI79 likes this.
  18. RI79

    RI79 Member Thread Starter

    Location:
    Rhode Island
    The shaft feels very firmly in place. The center of the top of the pulley appears convex, like it’s rounded outward, and there is a very small pinpoint opening in the center of the convex part — just a fraction of a millimeter. I think this is clear in the video, but apologies if not. The Rega pulleys I’ve seen online appear to have a 2mm opening at the top. Not sure how I’d replace this pulley if I couldn’t insert some acetone into the top to dissolve the glue that holds it in place. Anyone have any ideas on how I’d remove it considering the design?
     
    Glmoneydawg likes this.
  19. Glmoneydawg

    Glmoneydawg Forum Resident

    Location:
    Ontario Canada
    Hair dryer and a bearing puller....heat it up to melt the glue...and pull it off.
     
  20. Davey

    Davey NP: Principe Valiente ~ Barricades (2022)

    Location:
    SF Bay Area, USA
    What you see in the center is actually the motor shaft sticking out the top of the pulley, the pulley is shown online at many stores, should be like the one pictured below ... but if it isn't bothering you, nothing requiring you to fix it :)


    [​IMG]
     
    RI79 likes this.
  21. Glmoneydawg

    Glmoneydawg Forum Resident

    Location:
    Ontario Canada
    Much as i admire Rega tables....pulleys should be mounted with a set screw,this a bizarre setup.
     
    PooreBoy and avanti1960 like this.
  22. RI79

    RI79 Member Thread Starter

    Location:
    Rhode Island
    I really appreciate all of the info. Thanks, everyone.
     
  23. RI79

    RI79 Member Thread Starter

    Location:
    Rhode Island
    I believe the Michael Lim pulleys have a set screw. Not that I can find any way to purchase one.
     
    Glmoneydawg likes this.
  24. Davey

    Davey NP: Principe Valiente ~ Barricades (2022)

    Location:
    SF Bay Area, USA
    Our friend and resident Rega expert @KT88 will be along in a bit to tell you that we are all wrong, and give you the correct answer :)
     
    RI79, bluesaddict and Glmoneydawg like this.
  25. aorecords

    aorecords Forum Resident

    "Pulley wobble" sounds like something you'd find in Australia.

    Crikey! Did you see that Pulley Wobble over there. It almost bit me.
     
    Jeff Kent, BluTorch and Glmoneydawg like this.

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