Turntable decisions.

Discussion in 'Audio Hardware' started by Pythonman, Mar 11, 2018.

  1. Cosmo-D

    Cosmo-D Well-Known Member

    Location:
    Canada
    Wow & Flutter, speed deviation, rumble, et cetera. I've seen many threads that state the Regas don't do a very good job of running at 33RPM.
     
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  2. missan

    missan Forum Resident

    Location:
    Stockholm
    There is no advantage with a lighter design.
     
  3. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    The way Rega reasons it is that vibrations go in and out of the table very quickly instead of being stored. They have the calculations for it too Im sure.
     
  4. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    Those specs are available. The wow and flutter tolerance for P3s and P6s is a maximum of 0.30% for example.
    And your definition of very good varies to others. It also depends on which model we are talking about.
     
  5. Pythonman

    Pythonman Forum Resident Thread Starter

    I don’t really care that Rega doesn’t publish specifics about rumble or anything else. It’s never been proven to me how exactly numbers translate into specific sonic signatures or parameters that are meaningful anyway.

    Thorens!! I have a longstanding love of the old designs. I too briefly owned a new TD318
    back in 1987 but it had a tick in the motor which was audible and the shop refused order another and instead offered me a Systemdek or a CD player. I took the CD player lol. Later on I snagged a pristine TD125 with an SME 3009 arm which I later gave to a friend. Nice tables. Would like very much a TD160 in good order down the road.

    I’m surprised nobody has recommended a Kuzma Stabi? Where’s your sense of adventure here haahaa?! That was my first choice for awhile and has been relegated to third choice however. My friend with the Prime kidded me the Kuzma looked like a bug sprayer, I OTOH thought it looked like someone kicked over a tire pump and stuck a wagon wheel on it. Great arm and good sounding unit overall.
     
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  6. Cosmo-D

    Cosmo-D Well-Known Member

    Location:
    Canada
    I've never been able find them on the Rega site. And wow and flutter of 0.3% is terrible. I just fixed up a Dual 505-2 which has w&f of 0.05% WRMS. A Dual 505 is pretty cheap deck. There are several different means of evaluating w&f, but 0.3% is worse than any turntable I've ever seen.
     
  7. Cosmo-D

    Cosmo-D Well-Known Member

    Location:
    Canada
    More rumble is never good. I don't know the exact methodology they use for measuring it (that is something I would like to know) but it is supposed to represent the amount of mechanical noise relative to a reference signal. A lower number (remember rumble is supposed to be a negative value) is better. It's a measure of loud the mechanical apparatus is. How is that not meaningful? If you have two turntables and the rumble is measured the same way you can know which one noisier. If you own a turntable that makes a lot of mechanical noise you can look up its rumble figures and conclude that the amount of rumble it has is indeed audible. You can use it as a benchmark. It's a useful thing to know.

    And a turntable shouldn't have a "sonic signature". If the turntable is somehow influencing the frequency response from the cartridge in meaningful then there is something wrong. Rumble occurs at the frequency of the vibration of the motor and then the harmonics. The lower the frequency the better. DD turntables are preferable because they spin at low speed (there are also design other design considerations that give DD tables an advantage in terms of rumble). Belt-drives spin at higher frequency, thus increasing the likelihood that vibrations or the harmonics of those will interfere with audible frequencies.

    Below a certain threshold rumble is probably a non-issue. It's still probably useful to measure it. There is no reason Rega can't come up with some measurements.
     
  8. Pythonman

    Pythonman Forum Resident Thread Starter

    True a turntable should not have a sonic signature but almost every single one has some sort of either sonic signature or colorations or character that distinguishes it. And some much more than others.
    I really wouldn’t like to debate the merits of DD motors nor belt drives. Suffice it to say each method has their own set of strengths and leave it at that. Belt drive tables simply are more fascinating to me at this point in time in the way a completely mechanical watch movement vs a battery powered watch is.
     
  9. Cosmo-D

    Cosmo-D Well-Known Member

    Location:
    Canada
    That would mean that it is propagating the mechanical waves. Instead of thinking of it as "vibrations" think of it as "heat". Let's say our motor is generating "heat". What Rega is doing would be like wrapping your hands in aluminum foil to use as oven mitts. The foil is going to readily conduct heat. However, if you used a greater mass of aluminum foil you'd be able to keep your hands cool for longer. The "heat" goes in and out of our foil mitts readily, yet our hands are being burned. To protect our hands we'd be better served by using a material that can absorb more "heat" and that doesn't readily transfer it.

    Does my analogy make sense? I hope it does because I spent a while thinking on it. Obviously the analogy isn't perfect.
     
  10. chervokas

    chervokas Forum Resident

    Except they don't really go really go out of the Rega tables very quickly. Put a stethoscope to the plinth of a Rega when music is playing some time, the plinth is like a sound board holding on to the cart vibrations and motor vibrations being transmitted to it.
     
  11. Gibsonian

    Gibsonian Forum Resident

    Location:
    Iowa, USA
    Mass is my friend, a trusted ally :)
     
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  12. chervokas

    chervokas Forum Resident


    Massive things can vibrate, they just vibrate at different rates and different frequencies than less massive things. And in fact they can be slower to stop vibrating than lighter things but yes sometimes they can take more energy to get moving (but less so at the resonant frequency of the material in question). I'm not engineers, but as I understand it, there are only a couple of ways to deal with spurious vibrations -- you can convert them to some other kind of energy, like heat, that's more readily dissipated and/or not likely to impact the mechanical elements of turntable playback; or you can drain or divert it from one thing into another; or you can tune it. You can also try to minimize it at the source -- you need to use a motor to drive a turntable platter, and in order to drive the platter it has to be coupled to the platter, but different kinds of motors have greater or lesser cogging torque which might cause transmitted vibrations, some turntables mount mount the motor on some different structure from the tonearm mounting so at least the motor is not coupled to the tonearm, etc.
     
  13. swvahokie

    swvahokie Forum Resident

    In a direct drive, the platter bearing is actually a part of the motor. Any motor noise is 100% going into that platter, so it has to be dissipated. The best way to do that is mass. A good direct drive is going to be heavy, it has to be. Heavy plinth and platter.

    A belt drive the motor is mounted away from the platter bearing. The noise can be dealt with in a couple of ways, lots of mass like in a direct drive to turn the noise into heat, or isolating the motor noise from the platter bearings. Some companies use a completely separate motor pod. This can work very well, but the platform the table sits on becomes part of the table itself. The noise can travel through the platform back into the motor bearing. Rega does it by reducing the mass in the plinth and putting all the mass into the platter. As you go up in price in the Rega line, the plinths get lighter and the platter assemblies get heavier. The noise goes into the plinth, but the very light plinth cannot transmit the noise into the heavy platter or into the arm base. Rega does use light and very rigid braces to attach the arm base and the platter bearing together. It does work, they sound good.

    How is this for an analogy. A Prius is sitting on a railway crossing. A two mile long train is traveling at two miles an hour and hits the Prius. After the collision, what happens to the Prius. Does the train transmit its energy efficiently into the Prius? I don't think you want to be in that car to find out. Now reverse the situation, The train engines are sitting on the crossing, the Prius is traveling 60 mph and hits the engine. The much lighter Prius is not going to transmit very much of its energy into that locomotive.
     
  14. chervokas

    chervokas Forum Resident


    Except you never get the mechanical resonances of a turntable/tonearm/cart system to zero, so there always is a "sonic signature." Also, manufacturer produced and provided specs always present something in the best possible light, they're sales pieces. How often do you match in real world driving the gas mileage spec of a car? Not often. Third-party measurements are useful. Specs, they're useful, but shouldn't be held up as gospel. All drive mechanisms have pluses and minuses and in any implementation exists on a spectrum.

    Have you seen the famous B&K paper on turntable resonances from the late '70s? Old study but the one that kind of touched off a lot of the design focus on this stuff -- http://www.laudioexperience.fr/wp-c...-Resonances-in-Turntables-AN17-233-1977-1.pdf
     
    Last edited: Mar 12, 2018
  15. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    0.30% is the maximum variation allowed before its called a faulty product. The real question is if you can hear those potential differences and the answer is probably no. I could equally say that 0.05 is terrible. And Im sure the manufacturing specs are not that number, its just that specific table which runs with those numbers. A Rega could also run below the 0.1% if given the optimal conditions.
     
  16. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    I suppose it does make sense, but like you I dont have the Rega calculations. Also the analogy doesnt seem to incorporate stiffness in any way. Its not like Rega just makes their table out of cardboard to make it lighter, and usually the Platter serves as the heavier part.
     
  17. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    Are you saying that Rega is not aware of this or that it somehow helps playback?
     
  18. swvahokie

    swvahokie Forum Resident

    It doesn't help playback at all. The energy will effect playback if it can be transmitted into the platter bearing or arm base. The least effective Rega in minimizing this noise from being transmitted is the P1. The P1 has the most mass in the plinth, no bracing, and the lightest platter. As you go up the line, the players mass is transferred from the plinth to the platter, and bracing is added to make the platter bearing/arm base into a rigid beam. As the plinths get lighter and the platter/arm assemblies get heavier and more rigid, the noise isnt being transmitted as efficiently. You can probably still hear it with a stethoscope, but it is not being transmitted into the platter/arm assemblies.

    Placing a stethoscope onto a high mass tables plinth will tell you how that table is going to sound, you can bet on that. If that high mass plinth is ringing, that table is going to be compromised. The high mass will transmit the noise. But, in a good high mass table, you are not going to hear much if any thing in its plinth. In a Rega design, that stethoscope needs to be mounted on the platter or arm base. If you can still hear the noise, the player is compromised. Both designs can and do work if properly implemented.
     
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  19. Ken Clark

    Ken Clark Forum Resident

    Location:
    Chicago Suburbs
    I really don't think you can go wrong with either VPI or Rega. Do you have a cartridge in mind you plan to use? What phono stage? This might help the decision and would have more of an influence on making your speakers disappear as you suggest than the actual turntable.
     
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  20. swvahokie

    swvahokie Forum Resident

    I know where a dealer demo RP8 is for sale if anyone wants it.
     
  21. missan

    missan Forum Resident

    Location:
    Stockholm

    I don´t think we can say that. What is driving the platter is the rotating magnetic field, which will affect less than a belt. The motor isn´t really physically part of the platter, and as for the platter bearing there is really no difference to a belt drive.

    What I have measured the rumble/noise is especially low on a DD, and for reasons.
     
  22. Pythonman

    Pythonman Forum Resident Thread Starter

    None of the associated equipment is set in stone. Right now I’m looking at possibly a Hana EH, Dynavector 10x5 or 20x2 if I go with VPI or a combination of a Denon DL103+Black Cube or Ifi Iphono or Rega Exact if I go with the RP8.

    Right now I’m using a Rega BrioR for the main muscle of my system. It was bought new as something to tie me over while I was considering repairing my vintage McIntosh MC2505 amp and I ended up liking the Brio so much I sold the McIntosh amp plus the Mac MX112 preamp tuner for the same cash I had in the Brio. Naturally I have been studying up on more powerful and better sounding units including those from Rega and will upgrade there soon as well.
     
  23. swvahokie

    swvahokie Forum Resident

    The shaft inside the armature is what the platter sits on. Tell me how that is not part of the motor? The magnetic field does drive it, but the shaft turns inside bearings that are inside the motor. Those bearings provide a direct path for noise to enter the platter, and it most assuredly does. The secret is how much is generated and how much gets transmitted. This is just as important as using coreless motors and sophisticated drive systems. There is no magic bullet for direct drive tables just as there is no perfect belt drive. Both have compromises that take great engineering and unfortunately, money to solve.

    Direct drive can make a truly great turntable, but it wont be cheap. The only reason the 1200GR is under $2000 is due to Panasonics massive resources. Same for the 1200G at 4k.
     
  24. Strat-Mangler

    Strat-Mangler Forum Resident

    Location:
    Toronto
    Do yourself a favor and avoid iFi gear at all cost. There's a long thread on the company's unreliable iPhone 2 product, their terrible customer service, and a few members' issues even after going through multiple units.

    Sounds like you have a lot of possible configurations in mind, none of them weak, IMHO. I'm sure you'll quite enjoy whichever one you end up with. :)
     
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  25. swvahokie

    swvahokie Forum Resident

    Beat me to it, I was just getting ready to post the same thing!
     
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