Replacing older pivot bearing on Classic 3 with spike-only

Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby Votan » Sat Nov 30, 2019 3:22 am

Without even questioning the aforementioned advantages of the new spike, some might miss the damping caused by the viscous liquid in the older cup-cone spike, which to some extent covered a slight sound distortion due to inferior VTA tower and Dogleg Design and support of the older tonearms.
If there is any such issue, it might help an additional DIY support of Dogleg and VTA Tower
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby tom collins » Sat Nov 30, 2019 8:22 am

Good subject as I just tried this out just this week. I have the 12.0 base and a 12.0 armwand and 12.7 wand which is my regular setup. I got to thinking about the differences between the 12.0 base and the 12.7 base The 12.0 base allows the dogleg which supports the spike, wand and arm rest to hang in space and it is not a very thick piece of metal as compared to the 12.7 base which is far more rigid by virtue of the second dogleg and post which supports the extended part of the dogleg. My experiment was to find something that would fit snugly, but not too tight, between the bottom of the front of the dogleg (out by the armrest) but that would not change the adjustment of the pivot spike by pushing the dogleg up.
My solution came when I remembered a small box I have of speaker spikes that I am no longer using at this time. I was hoping to find one that was just a little short and add a nut on the screw end of the spike that allows a small amount of adjustment to lengthen the spike by using the screw adjuster. The base of the nut, placed on the plinth also serves to stabilize the spike. I set the arm up with the Feikart software and don't adjust VTA for each record, so the ability to change VTA on the fly does not really affect me.
With the first record I played, I noticed the diction in lyrics became clearer and the overall character was more bouncy and dynamic. I will spend a few weeks deciding if this is an improvement or just a change. You can see, I tried a second one, but did not hear the change as much as adding the first one.
I would ask anyone who tries this to post back with their impressions.
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arm support points.jpg
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby Votan » Sat Nov 30, 2019 1:20 pm

Hi tom collins,
The solution you used has also been extensively discussed in the resent thread: viewtopic.php?f=12&t=13261, where there are many alternative solutions, as well as impressions from their application.
As far as your version is concerned, I would recommend that you try the spikes completely upside down than you have put them. This is because-theoretically at least-your version facilitates the external vibrations to enter the dogleg, while instead hinder the energy produced by the cartridge to be drained-grounded easily and quickly on the plinth-Earth.
My version in this case is shown in the next photo.
20191123_081848.jpg
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby tom collins » Sat Nov 30, 2019 1:36 pm

yours is quite an engineering feat. i was just trying something simple but thanks for the suggestion.
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby Zongo Chief » Sun Dec 01, 2019 5:35 pm

Is it possible to do the reverse? (Replace the spike that came with my 3D wand with a damping cup spike so that I van use damping fluid)
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby masluck1 » Sun Dec 01, 2019 8:15 pm

Hi,

I too have the 12.0 base (and 12.0 wand) and removable arm board of a TNT IV. Looking at what Votan has published related to the dogleg and tower mods, I would like to take a step back to see if there is anything that can be done to fix the sloppy play I have in my removable arm board itself - there is a bit more there than should be, IMHO. Some of what he proposed (bracing in (2) places on the dog leg assembly) doesn't seem possible on a removable arm board style table, but that is another discussion. To compensate for the loose fit, I have inserted pieces of a paper based drink coaster in there to stop it from moving but am seeking something better (i.e. screws, clamps, etc.). I know BRF has stated the boards come in two sizes, but since this is my first (yet, somewhat ancient) VPI table, I am unsure if this is normal (NB: I haven't measured the board or the slot, yet). If this is normal, has anyone thought about ways to help compensate having the older TNT type arm boards fit a bit more secure (other that making a new one from wood or acrylic, so that it would fit securely with very minimal play)? Thanks!

Mark
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby Brf » Mon Dec 02, 2019 9:02 am

masluck1 wrote:Hi,

I too have the 12.0 base (and 12.0 wand) and removable arm board of a TNT IV. Looking at what Votan has published related to the dogleg and tower mods, I would like to take a step back to see if there is anything that can be done to fix the sloppy play I have in my removable arm board itself - there is a bit more there than should be, IMHO. Some of what he proposed (bracing in (2) places on the dog leg assembly) doesn't seem possible on a removable arm board style table, but that is another discussion. To compensate for the loose fit, I have inserted pieces of a paper based drink coaster in there to stop it from moving but am seeking something better (i.e. screws, clamps, etc.). I know BRF has stated the boards come in two sizes, but since this is my first (yet, somewhat ancient) VPI table, I am unsure if this is normal (NB: I haven't measured the board or the slot, yet). If this is normal, has anyone thought about ways to help compensate having the older TNT type arm boards fit a bit more secure (other that making a new one from wood or acrylic, so that it would fit securely with very minimal play)? Thanks!

Mark


Mark, the TNT removable arm boards are designed to be firmly secured to the plinth with the use of 6 cap screw bolts that thread from underneath the plinth into the arm board. Done correctly, there should be zero play in the arm board. Is you arm board not secured by the cap screw bolts?
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby Votan » Mon Dec 02, 2019 9:39 am

Zongo Chief wrote:Is it possible to do the reverse? (Replace the spike that came with my 3D wand with a damping cup spike so that I van use damping fluid)

I don't know if what you're asking for is possible (I assume the cup-cone in place of spike is possible, since it's possible the opposite, but I don't know if the cup-cone fits in the 3D bell cavity).
But I wonder why you would do that? The 3D tonearm is so much smoother than the metallic one, so there is no need to calm it with the damping fluid, as it might be needed in the most resonant metallic.
Apart from that, the spike has a significantly smaller friction in pivot point than the cup-cone (I speak from personal experience since I have used both) giving enviable freedom and friction free movement of the arm and this is distinctly and welcome listenable.
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby masluck1 » Mon Dec 02, 2019 9:42 am

Hi brf,

I just checked and I do in fact have the holes there, but no screws and that is the way I got it from the previous owner. I didn't know enough to ask and this solves a mystery, so I can't thank you enough!!! Can you tell me what kind they are (i.e. size/pitch) and maybe I can source them locally if they are not to hard to come by. Also, if VPI still has them, maybe I can get them from them...dunno...thanks again!!!

Mark
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Re: Replacing older pivot bearing on Classic 3 with spike-on

Postby Brf » Mon Dec 02, 2019 10:24 am

masluck1 wrote:Hi brf,

I just checked and I do in fact have the holes there, but no screws and that is the way I got it from the previous owner. I didn't know enough to ask and this solves a mystery, so I can't thank you enough!!! Can you tell me what kind they are (i.e. size/pitch) and maybe I can source them locally if they are not to hard to come by. Also, if VPI still has them, maybe I can get them from them...dunno...thanks again!!!

Mark


Sorry, I don't recall off hand the length and size of the socket head cap screw but they are fairly common. The arm board is tapped for the correct sized diameter and pitch, therefore, you could take you arm board to a hardware store to match the correct size. For length, just make sure that the socket head cap screw clears the plinth holes and allows a 1/2" of thread to go into the arm board.
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