Eminent Technology ET-2 Tonearm Owners

Richard - I was thinking about what you posted. If using a run of 40 feet, there is enough "space" within that tubing to allow the tubing to act like a surge tank when used with a regulator at the other end. This was explained to me years ago by the shop where I got my fittings. When the tubing material is soft there is also a greater chance that the tubing will expand and contract to deal with changes in temp/humidity and the air supply. If you have a regulator at the end of it "prior" to the tonearm you can regulate it and thus the surge tank analogy. You don't need 40 feet of actual house space to get these benefits. You can just coil up the tubing in an area.

Now some I have known choose to have long runs, straight in to the tonearm manifold, meaning the tonearm air bearing spindle could be experiencing air flow changes as the record plays. Especially if the air source is not steady or in a different part of the house; different temp, humidity etc. I imagine this can make for some interesting music ?

I am using fairly rigid white poly for the main run to the in room regulator. Its a perilous journey around corners and through a wall. Its quite stiff and rigid, it won't kink and is very easy to feed through tight areas. Its the same tube material they use in house town water 3/4 inch plumbing with sharkbite connections. Its doesn't expand and contract with temperature/humidity changes. The short run from the in room regulator to the tonearm is clear tubing. Cheers

Richard and Chris, I have always had a 50' spool of excess (unnecessary; length-wise) clear and fairly rigid tubing between the pump and my surge tank. Like Chris mentioned, the coil of tubing will act as a surge tank. I was able to confirm the benefits of doing this when my previous surge tank exploded and I needed something in the interim.

I am intrigued by the comments re soft vs rigid tubing. I have not experimented with the two versions and logic seems to suggest that rigid would be better as Chris says. However, might it be possible that the air pressure causes the soft tubing to expand and actually create an effectively wider-diameter tube, thus increasing the "surge tank effect"; and, why the soft/clear sounded better?

Like someone recently said, this is mad-scientist territory.

Chris, thanks for the links. A very important topic and one that is not understood by many music consumers. Music is such a personal thing for most of us ("Those eyes!") that it causes most listeners to think of themselves as music lovers vs the more clinical "consumer". In fact, music is a product like any other, and it's creators are entitled to fair compensation for its consumption. I have never understood why many feel a sense of entitlement to essentially steal that product; no different than shoplifting. I remember well when the SNL band had to pull all the charts of Beatles tunes out of our book because it was simply too expensive to perform them. As with most things, what is ultimately paid is negotiable; and, The Beatles, being The Beatles, have no incentive to negotiate anything. It may seem unfortunate, but I say more power to them.

Frogman et al,
There are many reasons why different tubes will affect the sound.
Depending upon the velocity, the air is likely to flow chaotically, forming vortexes and eddies as it moves down the pipe, it is not necessarily laminar.
The geometry of the tube, the roughness of the tube walls, the elasticity of the tube and the purity of the air all affect flow and chaotic behaviour.
Furthermore, air is compressible, which affects flow. And finally as air flows, compresses or decompresses, it can change temperature which affects pressure and therefore flow.
Keeping the tube as straight as possible will reduce turbulence, just like an optical cable with digital - oh the irony.
It is quite complex.

As an aside I would have thought it would be advantageous to have a regulator at the end of the long tube, just prior to the arm, as the length of tube after the regulator will, if my rusty memory on fluid dynamics is working, drop the flow rate going into the bearing.

In other words if 2 of you had the same regulator and 40ft of tube, and one places the regulator at the start of the tube, and the other places the regulator at the end of the tube, then I would expect that you would end up with different flow rates into the bearing. I would at the very least expect a significant impact on the "sound" from where you position the final regulator in relation to the arm bearing.

Suggested music for AB testing - JS Bach Air on the G String : Zoltan Rozsnyai/Philharmonia Hungarica on M&K Realtime for the audiophiles, perhaps Malcolm Sargent/New Symphony Orchestra for the purists on HMV ( 78rpm of course ).

Very interesting, Dover. Thanks for the explanations and music recs.

Regards.