Eminent Technology ET-2 Tonearm Owners

Chris.

The config was not quite as you wrote.

In both iterations I used two regulators. The one in the compressor and a separate stand alone Norgren model.
Basically I slid the second regulator along a 43 foot length of clear soft PVC tube to position it either within 3 feet of the arm or 40 ft of the arm. This to test my theory that regulators themselves introduce tiny pressure perturbations which can be smoothed by the long run of flexible tube.
So, yes I believe that I have introduced a more consistent air delivery to the manifold. The key though for owners that have in-room regs close to the arm, is that the regs may be doing harm to the sound.

Note I made no change to the air supply circuit, just its configuration.

The pressure gauge is right next to the arm and I adjusted the second regulator pressure output such that the arm received the same pressure for the two configurations. So a spindle resonating problem would have shown up in both configurations. Further I know what excessive pressure sounds like and this was not what occurred last night.

The arm has a high pressure manifold. What actual design pressure? Don't know, but 17 to 18 psi with an oil trough works best.

Yes I tried different records and VTA settings. I did not remove the oil trough.
Findings were consistent across all the tests.

This would be very easy for you to try.
Just significantly increase the length of clear 1/4" PVC tube from the outlet of your in-room regulator to the arm. You will need to slightly (very slightly) increase the reg pressure to ensure that the arm sees the same input pressure due to a small line loss in the longer tube.
Now I know that this is not quite the same test as I did since you will be adding extra tubing but it will, I'm sure be informative.

Yep, I am well aware of the "better equals worse" scenario. Have gone down that dark alley many times.
Pretty sure that this is not one of those.

Their was no ambiguity at all with my findings in my rig.

Also just adding another finding from some years back.
The air stream needs to be earthed close to the arm. In my case, I earth the body of the pressure gauge which has a metal sensor that touches the air flow. Static build up?

cheers.

Richard
what a great and crazy hobby this is. We are running two very different air pump /tubing systems. Also our tonearms although they share some parts are more different in their construction and their setup requirements. We are using very different turntables, the amps, pre? and the most important thing - our rooms are different.
I'd say so far we are on par for the course like any other two audio guys/gals in this hobby ?
oh yeah.....and we are discussing the effects of changing out a length of air hose in the middle of all this stuff. Wonderful hobby.

There is one thing that stands out from your posts like a square peg in a round role to me. I run the same PSI with and without the damping trough, as designed by Bruce.
Its effects are real but subtle. Why are you not able to run the same psi without the trough ? I think you said the differences with and without are as high as 5 psi. Now understand I am not losing sleep over this - my kids give me enough reason for sleepless nights. something just doesn't jive. But as your arm is a customized, unique one, I don't really feel a need to understand why - was just curious.
That plus you don't just live down the street from me; if you know what I mean.
As long as you are happy....cool.

I have had my happy music lover's hat on for over 6 months.
If I choose to put on the audiophile hat one day again with vinyl, I can try tweaking with the air tubes as discussed.
The difference between MY two hats is that my music lover hat fits really well.
My audiophile hat for some strange reason has become a 1/2 size to small for me.
Happy Listening.

Chris.
"great crazy hobby this is. We are running two very different......"
Yes but isn't diversity the spice of life!

My pre is my own, all tube design, well actually my own unique combination of known gain blocks with some interesting P/S features. It exists in a family of one, world wide.

I wish I did live just down the street. I suspect that it would be a lot of fun.

Yes, I freely admit that the pressure disparity with and without the trough is interesting. Maybe I will revisit this, but the oil trough change was big in my rig even at 12 psi each way, it just got better, with the trough, as I pushed it up to 18.

If your kids are like mine, they will continue to give you sleepless nights for many years to come....sorry about that!

Richard, et al.

fyi - Bruce' opinion on PSI changes versus Quality Air Supply.
I didn't want to interrupt Bruce' Elephant hearing study so I kept my question short.

Bruce
If a friend made a significant change to the air delivery system on his ET2 and this caused audible changes like soundstage and other audiophile type attributes, attack, decay, to change .... do you have an opinion re: PSI changes versus the Air Supply itself.

More than air pressure, the air supply will change the sound of the tonearm if it is bad, allowing pressure pulsations to enter the manifold. Increasing pressure slightly and a big enough surge tank are the best things that could be added to the tonearm in terms of performance. Not knowing anything about the pump changes, I don't have much to offer. Thank you and I apologize for the delay in getting back to you.

brucet

key words to me "increasing pressure slightly" and "big enough surge tank"
This applies to unmodified ET2.0 and ET 2.5

Richard - An observation. I spent the weekend on the water boating and sometimes in the water - this was by accident as the temp is still only in the 70's. What was very obvious is that even with similar size boats but with different size/horsepower motors; the ones that had their prop set up properly....were able to skim the water, go on plane and performed far better than those similar boats with motors too large / long that had props that slugged lower through the water.
Where am I going with this ? Lets play crazy scientist again and assume that the prop in the water is like the tonearm's paddle in the oil.
I was puzzled with the big performance differences between your oil and non oil damped settings. Could your paddle be in the oil more; and the oil is acting as a cushion for your modded spindle as it goes back and forth with the lp? Just a thought. I am using just 1 cc of oil and the paddle is barely skimming the oil. fwiw - the oil in the trough also acts as a great visual level as well.

Are you a skimmer or a slugger ?

:^) fun hobby. Happy listening.