Creative and cheap DIY turntable/tonearm tweaks

Adding any material to your tonearm cavities will significantly change the effective mass of the arm. Be careful. Sand is completely out of the question. Also, it is not true that "the more acoustically dead, the better". There must be a balance struck between damping and "liveliness" or your music will be dead. This is not something for a newbie to be fussing with, unless you have money to burn.

The Teres 255 platter has the chambers filled with lead shot. Adding a liquid has been thought of, and it is a problem with sealing the chambers against leaks.

I have done a number of mods to arms and tables. Search the archives for my threads on mods.

Jyprez. The increase in vertical mass is the problem with adding the sand. So it is distinguishable(in terms of physics) from my tonearm mod, because my mod does not affect vertical mass. I assure you if you load your arm with sand, you will be unhappy with the result. Warp tracking will be hideous.

Yes, I calculated the horizontal mass increase in my tonearm mod. And the distance of the weights is 1.75" outside the center of the pivot on both sides, so there is an increase in inertia from the length of the outriggers, as well as just the pure mass. This mod works, and is calculable, and proven in testing.

As far as credibility goes, you may do as much analysis of it as you like. It is not for sale, so it makes no difference to me whether anybody likes it or not. Several testers as well as myself are enjoying some significant benefits from this mod. Very few others even showed any interest. So no hype is necessary, because anybody that wants it can make it themselves, and if they don't want it, I don't care. I have given up trying to convince people. Now I just post my information, and leave it at that.

Since the groove walls are angled, there is inevitably some stylus movement in the vertical plane. But there are very big vertical movements when a warp in the record is encountered. A large mass will actually leave contact with the record after being "thrown" up in the air by the warp. Then it will come back down at some later point of the record. This is generally not desireable. Typically, designers will make the arm as light-mass in the vertical plane as is practical. This normally also sacrifices horizontal mass, and was the reason for my tonearm mod, which separates and allows different mass in the horizontal and vertical planes. When an arm is not designed to have independent vertical and horizontal masses, then there is an inevitable compromise between light vertical mass for warp tracking, and heavier horizontal mass for cartridge stability. One or the other will suffer from the compromise. I promise that I did my homework.

Bob, I believe the mod as I applied it is forgiving of the larger movements of record eccentricities. And it seems to have no effect on the slow tracking of the spiral groove as it traverses the record. I have no "wildly" eccentric records in my collection, so I don't know if this will be a problem for the arm with my mod, but I am considering the effectiveness on a "normal" LP to be of greater importance than its performance on a "defective" LP.
Yes, I'm aware of the Polar Moment of Inertia, thanks for reminding me.
I'd like to hear what results you get, especially on the really badly eccentric records.
I'd also like to remind you that the benefits of this mod will become smaller in effect with higher compliance cartridges, and will be of no use at all with very high compliance cartridges. I have tested cartridges up to 15cu with Rega arms, and they are still getting benefits from this mod. How much higher in compliance you can go, without losing effectiveness entirely, is unknown to me at this time. I would say, though, that any cartridge that would normally be considered a good resonance match with a Rega arm, would receive some benefits.