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  • #76
    Originally posted by Joe Pittman View Post
    The Dual Pivot is now my standard preferred accessory and provides a little better performance IMHO. The ability to precisely adjust azimuth is an added bonus. I finally got around to changing the stock screw points with precision 1.5 mm Ruby ball tipped screw (actually sapphire, Grade 25) on my three VPI arms.

    The arm is constantly moving and causes the point to grind into the thrust plate. This creates a kind of mechanical jitter in my opinion.

    I like the sound of the smooth Ruby ball much better, it also has very low friction. This is a low cost mod.

    Click image for larger version Name:	VPI Dual Pivot Screw with Ruby Ball.jpg Views:	1 Size:	219.3 KB ID:	83852
    I’ve played with various jeweled pivot points with mixed results. In theory, a harder, smoother surface will provide less friction. The challenge I found with a jeweled pivot was finding a ruby ball small enough to approximate the polished stainless steel tip. Commercially available ruby balls that I found offered a smoother and harder surface than the stainless steel tip, but had a contact area much larger than SS tip which results in a larger frictional surface area.

    I also tested the effect of lowering the pivot point friction by using a lubricant to see if it made an audible difference. I used molybdenum disulfide which is a dry lubricate used to seal microporosities that causes friction. I could not discern an audible difference.

    I have since abandoned my quest for reduced friction between standard pivot point and SS skate plate.

    Note: The issue with using a lubricant for an extended period of time is that it will attract contaminants, therefore, the effects will be short lived and it will require constant cleaning and reapplication due to the simple fact that it is not in a closed system.

    Comment


    • #77
      Welcome to audionirvana, Brent.
      Analog: Forsell Air Reference, Transfiguration Proteus; VPI Prime Signature, VdH Crimson XGW, Transfiguration Phoenix S, VAS Nova Mono;
      Unmounted: VAS Nova Signature, Symphonic Line RG-8

      Digital: Mac mini 6,2 with YFS PS-12M LPS; Exogal Comet Plus, Exogal Ion PowerDAC
      Electronics: Aurorasound Vida, Channel D Lino C; Merrill Cara, Gryphon XT MC; Merrill Thor, Gryphon M-100 Mkii
      Cables: Morrow, Gryphon interconnects; YFS USB cable; Morrow, XLO, Channel D phono cables; Gryphon speaker cables

      Comment


      • #78
        Hi Myles and all,
        I regret being fairly nonexistent around here! Lots of work, thankfully.
        I have a 2 week old VPI "Super" Prime Scout, and I'm loving it! But always reaching for the best that I can get for reasonable money, I'm wondering if you folks are still sold on the dual pivot mod. Thanks and happy listening!
        Jenn

        Comment


        • #79
          Originally posted by JennMartin View Post
          Hi Myles and all,
          I regret being fairly nonexistent around here! Lots of work, thankfully.
          I have a 2 week old VPI "Super" Prime Scout, and I'm loving it! But always reaching for the best that I can get for reasonable money, I'm wondering if you folks are still sold on the dual pivot mod. Thanks and happy listening!
          Jenn
          Yes it is a worthy sonic upgrade. Plus some just like the feel better. I'm hard pressed to think of a better $150 upgrade.

          My only issue has been VPI's going to a round CW like on the new Fatboy and loading the dual pivot. Ugh. But there's no issue with the elliptical shaped CW.
          Myles B. Astor, PhD, Administrator
          Senior Editor, Positive-Feedback.com
          ________________________________________

          -Magico S5 Mk.2 speakers with SPod feet
          -Goldmund Telos 280 stereo amp
          -Goldmund Mimesis 37S Nextgen preamplifier
          -Doshi V3.0 phonostage
          -VPI Vanquish direct-drive turntable
          -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
          -Lyra Atlas SL Lambda, Fuuga, vdh Colibri Master Signature, MutechHayabusa, MOFI Master Tracker, Sumiko Songbird cartridges
          -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
          -Assorted cables including Transparent XL Gen. 5, Skogrand, Viero, Kubala-Sosna, Audience Au24SX, Genesis Advanced Technologies and Ensemble Power Cords
          -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA platforms.

          Comment


          • #80
            Originally posted by MylesBAstor View Post
            My only issue has been VPI's going to a round CW like on the new Fatboy and loading the dual pivot. Ugh. But there's no issue with the elliptical shaped CW.
            Did you wind up adjusting the right side weight to load the dual pivot?
            Analog: Forsell Air Reference, Transfiguration Proteus; VPI Prime Signature, VdH Crimson XGW, Transfiguration Phoenix S, VAS Nova Mono;
            Unmounted: VAS Nova Signature, Symphonic Line RG-8

            Digital: Mac mini 6,2 with YFS PS-12M LPS; Exogal Comet Plus, Exogal Ion PowerDAC
            Electronics: Aurorasound Vida, Channel D Lino C; Merrill Cara, Gryphon XT MC; Merrill Thor, Gryphon M-100 Mkii
            Cables: Morrow, Gryphon interconnects; YFS USB cable; Morrow, XLO, Channel D phono cables; Gryphon speaker cables

            Comment


            • #81
              Originally posted by jonathanb View Post

              Did you wind up adjusting the right side weight to load the dual pivot?
              Yes, I had to pull a heavier outrigger weight off an older VPI arm. I couldn’t load the Fatboy dual pivot even with the lighter Lyra. I am hoping Mat makes a series of weights to help in loading.
              Myles B. Astor, PhD, Administrator
              Senior Editor, Positive-Feedback.com
              ________________________________________

              -Magico S5 Mk.2 speakers with SPod feet
              -Goldmund Telos 280 stereo amp
              -Goldmund Mimesis 37S Nextgen preamplifier
              -Doshi V3.0 phonostage
              -VPI Vanquish direct-drive turntable
              -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
              -Lyra Atlas SL Lambda, Fuuga, vdh Colibri Master Signature, MutechHayabusa, MOFI Master Tracker, Sumiko Songbird cartridges
              -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
              -Assorted cables including Transparent XL Gen. 5, Skogrand, Viero, Kubala-Sosna, Audience Au24SX, Genesis Advanced Technologies and Ensemble Power Cords
              -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA platforms.

              Comment


              • #82
                Jeff....the older 3D's have an access hole above the pivot....the newer ones have a cap over the hole....it looks like an emerging pimple or such. Its hard to remove that cap, but remove it you must to raise/lower the pivot point. I took a sharp new single edge razor blade and very carefully caught the edge of that pimple with the blade. Once its caught, you can readily lift it from its resting point. Be careful that it doesn't "pop" out to be lost forever. One of the best attributes of that 2nd pivot (aside from the very valuable increase in the fidelity of the sound) is that once the azimuth is set, it remains so. For 150 dollars its certainly at least worth a try

                Comment


                • #83
                  Originally posted by MylesBAstor View Post

                  Yes it is a worthy sonic upgrade. Plus some just like the feel better. I'm hard pressed to think of a better $150 upgrade.

                  My only issue has been VPI's going to a round CW like on the new Fatboy and loading the dual pivot. Ugh. But there's no issue with the elliptical shaped CW.
                  Thanks Myles!

                  Comment


                  • #84
                    Regarding counterweight .......If you need a heavier counterweight for the 3D (or any of its arms) VPI can accommodate. My counterweight has a mini-weight attached to properly balance my Ortofon. This little weight can be unscrewed if one needs to install a lighter cartridge.

                    Comment


                    • #85
                      Originally posted by Joe Pittman View Post
                      The Dual Pivot is now my standard preferred accessory and provides a little better performance IMHO. The ability to precisely adjust azimuth is an added bonus. I finally got around to changing the stock screw points with precision 1.5 mm Ruby ball tipped screw (actually sapphire, Grade 25) on my three VPI arms.

                      The arm is constantly moving and causes the point to grind into the thrust plate. This creates a kind of mechanical jitter in my opinion.

                      I like the sound of the smooth Ruby ball much better, it also has very low friction. This is a low cost mod.

                      Click image for larger version Name:	VPI Dual Pivot Screw with Ruby Ball.jpg Views:	1 Size:	219.3 KB ID:	83852
                      Please tell us where one may source the ruby tipped grub screw!

                      Thanks

                      Comment


                      • Joe Pittman
                        Joe Pittman commented
                        Editing a comment
                        I made my own ruby tipped screws. And they are easy to make. I'll make some more in a few months...

                    • #86
                      Joe - if you decide to make them available for sale, let me know. Thanks

                      Comment


                      • Letsmakeadeal
                        Letsmakeadeal commented
                        Editing a comment
                        I have the same only with brass setscrews (very hard to find) and tiny Grade 3 Ceramic balls...Free if you will cover shipping ($3-$4). I sent some to Brent. Not sure if he ever tried them. I have enough parts to probably make 20 or more of them. Since I am going to Gimballed Fatboys, I don't need them anymore. PM if interented.
                        Last edited by Letsmakeadeal; 11-26-2018, 10:35 AM.

                    • #87
                      Originally posted by Brf View Post

                      The challenge I found with a jeweled pivot was finding a ruby ball small enough to approximate the polished stainless steel tip. Commercially available ruby balls that I found offered a smoother and harder surface than the stainless steel tip, but had a contact area much larger than SS tip which results in a larger frictional surface area.
                      How can any sphere, no matter how big, have a larger contact area than the stainless steel tip? Unless there is material deflection, the ball should have an infinitely small contact area.

                      Comment


                      • #88
                        I finally got around to replacing the polished metal Pivot Surface of the Dual Pivot Assembly with Sapphire. When used with my Ruby Ball Tipped Screw, I now have a sapphire-to-sapphire contact. The performance of the stock kit is taken to a higher level. The Sapphire Pivot Surface is laboratory quality with ultra smooth and flat surface matching my Grade 5 Ruby Ball smoothness. Overall friction/stiction is extremely low. Very exciting.

                        Click image for larger version

Name:	KOSMIC Dual Pivot Kit Sapphire Pivot Surface Installed ON VPI Arm Base - 1000pix.jpg
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                        Click image for larger version

Name:	KOSMIC Dual Pivot Kit with Ruby Ball Tipped Screw and Sapphire Pivot Surface - 1000pix.jpg
Views:	287
Size:	320.2 KB
ID:	119543

                        Comment


                        • #89
                          To understand the scale of the problem, the contact between the spike and surface is less than 1/2" long playing a record. The "stiction" at the point of contact is significant. Zero Friction Perfection at the molecular level is the goal.

                          Click image for larger version

Name:	Dual Pivot Sapphire Pivot Surface Location.jpg
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ID:	119561

                          Comment


                          • #90
                            Nice work Joe, love the diagrams. I have played around with jewelled pivots and sapphire window skate plates since the dual pivot’s introduction. A few comments.

                            Stiction: I do not believe that the coefficient of static friction is an issue as the rotational torque generated by the lead in groove puts the dual pivot into motion prior to the stylus hitting a modulated music groove. I addition, the dual pivot is in constant motion throughout playback.

                            “the contact between the spike and surface is less than 1/2" long playing a record” – I am not 100% sure what you are implying but the relatively short path travelled by the dual pivot compared to the path of the stylus provides a mechanical advantage which will significantly negate the kinetic friction of the dual pivot. With respect to the kinetic friction caused by the dual pivot’s interface, I do not believe it to be that great (if properly loaded) as it does not cause any noticeable stylus deflection when employed.

                            I guess it all boils down to the friction of the dual pivot interface once in motion, and does its reduction have a positive result. I first tried a wet lubrication to reduce the friction caused by stainless steel on stainless steel interface. The lubrication significantly reduced the interface’s coefficient of friction, but long-term affects will be compromised, as a wet lube will attract air borne contaminants. I then swapped out the regular SS dual pivot with both a jewelled and a grade 3 Si3N ball, and added a sapphire window skate plate. To be 100% honest, I could not discern a different in sound between the different materials. I am not discounting others who report a sound improvement, but as much as I wanted to hear an improvement, I could not.

                            I encourage anyone curious about the dual pivot modification to try out Joe’s jewelled assembly, as the cost of entry is a bargain and who knows, it just may prove to be beneficial in your system.

                            Thanks Joe for pushing the envelope. BTW, I had a peak at you website http://www.kosmic.us/ .......very nice!
                            .

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