Eminent Technology ET-2 Tonearm Owners

Chris.

Even if you use a joiner, you will still be removing one regulator from the air circuit so it will not be a true AB test.

Yep agree, measurements only take you so far.
We don't listen to numbers.

Ok
Since I cooked dinner tonite, I got a leave pass afterwards...,

Have just finished trying the second regulator close to the arm.
There was just 3 feet of tube between it and the arm, the original configuration having 40 feet of tube. I adjusted the pressure to compensate for line losses.

With the regulator close, the soundstage shrunk both in width and depth. There is a subtle veil over the sound with attack and decay diminished.
The model of regulator I use is. Norgren B07-201-A1KG.
Looks like a pretty standard unit and appears similar to the photos posted here by various owners.

After an hour of going back and forth to confirm my findings, I couldn't wait to settle back to the original layout.......
Compressor with built in regulator- 4 ft PVC tube- needle valve bleed off- second regulator- 40 ft PVC tube- pressure gauge- arm.

The Norgren regulator does something to the air flow that the arm doesn't like. Having 40 ft of tube mitigates this.
I would be curious to read findings from others where a significant length of soft PVC tube was used between the reg and arm vs a short length of the same tube.

For my setup the long tube was clearly superior.

thanks for sharing impressions Richard.

With the regulator close, the soundstage shrunk both in width and depth. There is a subtle veil over the sound with attack and decay diminished.

Just recollecting.
When I was experimenting with PSI years ago, these are the same symptoms I encountered, when there was too much psi for the manifold and it caused the spindle to start resonating - affecting the cartridge.

So out of pure curiosity my questions would be:

1)What PSI is your manifold designed for ?
2)Did you try different records that required different VTA's during the comparison ?
3)Did you try it with and without the damping trough.

If you chose to compare again - I would go with a longer 6 foot section of tube to the arm and lower psi.

Maybe I misunderstood what you were trying to compare so let me confirm.
You went from this:

pump--------40 feet hose-----tonearm manifold

to this

pump--------40 feet hose---regulator -----3 feet hose ---- tonearm manifold.

If my crude flow chart is correct - you have imo introduced a more consistent air delivery into the manifold. The reason being alot can happen (changes)to the air in the 40 foot run.
Here is something to think about. Sometimes when we introduce something that in theory should work better, for reasons described above, it ends up sounding worse.

Well - what if better more consistent air delivery exposed a set up issue (i.e. too much psi)

Again just thinking out loud - remote troubleshooting is difficult with a one sentence description.

I do think its worth noting here again if anyone should pick up a used ET2 or ET2.5; and they do not know what PSI the manifold was set up for. One way to find out - put an old record on and start lowering pressure. When it starts skipping raise a few PSI. Fine tune final PSI by ear.

ymmv - water deposits from the air could have clogged the capillaries requiring more PSI to even work ! The manifolds are easily cleaned - instructions in the manual. If I bought an Et2 from an unknown source I would clean them before setup.

Cheers

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.