New Air Suspension Footers for VPI TNT

How do they perform? I heard a rumor that they don't do as good an isolation job as the reflatables. Would you refute this?

The stock HRX footers have been the leaky inflatables. They require reflation every several months. Perhaps VPI will make the sealed ball standard equipment going forward? If the sealed ball configuration offers same or better performance (vibration isolation), it would be a very popular upgrade since regular reflation is a dreadful chore.

I got the new suspension. Here are my experiences with the upgrade:

I ordered the HRX Footers from the Elusive Disc, a reputable retailer. They took a long time to come; availability was subject to VPI’s production schedule. Bob at Elusive was good at keeping me abreast of the ETA. Eventually, a box arrived with no instructions. This was apparently the kit for earlier, pre-HRX versions of the TNT, and it included everything I would need for the HRX as well. Each new footer came as three components, a rubber ball, a “tower,” and a “footer” with a cup for the ball on its top and a screwjack for making it taller or shorter for leveling the plinth.

The tower is shaped like a cylindrical tube with a dome on one end. The dome is dark grey plastic, although the cylindrical tube is covered by a silvery metal. Inside the tower, at its deep end, is a cup-shaped insert (cupped for the ball, of course). The insert is press fitted or very lightly glued into a cylindrical well drilled into the inside of the plastic dome. A modest tug on the cup shape (using needle-nosed pliers) was sufficient to pull the insert out of the cylindrical well in the plastic dome. After removing this cup-shaped insert, the rest of the tower was discarded. The cup-shape insert is to be installed into the existing HRX tower.

The existing HRX tower is integrally built into the HRX plinth, and there appears to be no way to remove it. Shape-wise, it is very similar to the tower component that came with the new kit – it is a cylindrical tube with a plastic dome on one end. In addition, it has a silvery metal surface that covers the plastic dome. There is a small hole drilled at the top of the metal surface, through which extends the air valve nipple for the existing air bladder suspension. The little metal cap that screws onto the nipple is all that holds the air bladder and footer assembly to the existing tower. (Without the metal cap, the footer falls out when the plinth is lifted off its shelf.)

After unscrewing the little metal cap and then removing the old footer, I let the air out and unscrewed and removed the metal valve assembly from the old air bladder (which was still attached to the old footer). The air bladder and the old footer were then discarded. I reinserted the valve stem through the hole in the metal surface and screwed the little metal cap onto it to secure it in place, so the tower’s appearance was preserved. (Could the metal cap and valve assembly be potential sources of noise/grundge? I haven't heard any so far.) I found that a bent and kinked coat hanger wire was useful for inserting into a hole in the valve assembly bottom to facilitate handling it while doing this.

The inside of the existing tower has a cylindrical well into which the cup-shaped insert can be located. Notably, the well is slightly too big for the insert. I wrapped black electrical tape around the insert three or four times to get a good press fit into the cylindrical well of this old tower. The coat hanger wire was useful for handling the insert as well, making use of a hole drilled through the insert. (Note the well is deep enough to accommodate the valve assembly without interfering with the press-fitted insert.) After that, all that remained was to put the ball on the upward facing cup on top of the new footer and insert this up into the interior of the old tower until the ball was captured by the downward-facing cup-shaped insert at the top.

After all four feet were refitted this way, I taped the footers to the towers so I could lift and replace the turntable back onto its shelf. After removing the tape, I adjusted the height screwjacks in each new footer to make sure the platter was level, using a bubble level.

I find that I am happier with the sound, although it is beyond my perceptivity and vocabulary to describe or quantify exactly how it has changed. Accordingly, I would describe the sound as the same or slightly better than before, without further expansion. For the record, my installation is well-braced in a corner and never had a resonance problem. I noticed a surprising degree of mental relief at never having to worry about bladder inflation again. I am also very pleased from a technical design-aesthetics perspective to be able to level the table reliably. In all, I thought it was a worthwhile upgrade, despite the cost.

Downunder,

Your link is correct. That was what I bought. Clearly, it SHOULD be possible to buy a kit for the HRX without the towers for less cost. Bob at Elusive told me that what I got was the only kit available at the time of my order. I think VPI COULD eventually offer the HRX upgrade for less; I would recommend inquiring about it directly. If you do, please let us know what they say!

I didn't find a lopsided effect at the right rear corner. The balls are reasonably stiff and don't give a whole lot unless the weight differential is really excessive. Also, I am using the Graham Phantom arm, which appears to weigh less than the stock JMW, not that the difference would be really noticeable with these balls. Lastly, the new towers have screwjacks that adjust for height, so any sag can be offset by jacking the sagging corner up a little.

Best Regards, James Wei

I don't know how long the balls are supposed to last. Estimates as to their longevity may be based on their use as paddleballs, which may be a harder use with a shorter life than in a table suspension. The good news is that they are off-the-shelf paddleballs that are commonly available and shouldn't cost a lot.

I would emphasize that a complete HRX kit should include at least both the upper and lower cup-shaped inserts and the footer foot with screwjacks for plinth leveling, as well as the paddle balls. (You all know the old footers have no screwjacks. If one subscribes to the view that leveling is not necessary, then using the old footers would be OK.} Black plugs for the tower top holes, as Gladstone mentioned, would be a better solution than re-installing the valve assemblies and metal caps, as I did.