Eminent Technology ET-2 Tonearm Owners

Chris.
You must have time on your hands to produce such a lengthy thoughtful tome.

I read it multiple times to try to get inside what you were saying. I think that you take BTs comments to mean that the o'rings will leak if a low pressure manifold is over pressured? I don't think that this is what he means.
I suggest that BT adjusts the arm design pressure by manipulating the clearance between the spindle OD and manifold ID and/or the way the capillaries are set up.
The push back at end of travel he talks about is due to excessive air flow exiting the gap between spindle and manifold bush, not due to the o'rings leaking.

The shims I have added are in the gap between the manifold outer plastic shell and inner aluminium bushing. This is the gap where the o'rings sit. The 2 shims about 2x3x**mm thick, each end, are spaced at 120 degree increments. Completing the circle at 120 degrees each end is one M2 grub screw. It is gently tightened to make a solid mechanical link between the manifold outer shell and the inner bush.

One would not consider removing the main arm to TT plinth mounting bolt and gluing the arm to the plinth with say rubber discs spacers in place of the three pointed screws, since this would be introducing a compliant joint between the arm and TT. But this is exactly what the o'rings do. They are a compliant joint.

The positive benefits of adding the shims and grub screws is unambiguous.

cheers.

Richard its never the best way to just cut and past portions of emails and other info into a thread. Whats missing is the rest of the email, and the valuable info obtained from verbal conversations.

Summary:
Pump/Surge tank ---- long tubing (if you don't have the room coil it up) ----- ET2
PSI Gauge/filter within 5 feet of the tonearm.
The PSI coming out of the air pump should be ideally targeted to match the PSI the manifold has been designed for. For those buying a used ET 2.0 (.5) its important to determine this. We have discussed the technique here. Before this technique is performed the manifold needs to be restored.

Definition of a manifold.

"A pipe or chamber branching into several openings"

Two Et2 Manifolds

The owner has provided permission for me to post these pics. Thank u !

The one on the left dirty from years of use without a filter/trap. The one on the right has been cleaned. What can't be seen in the pic is what the insides looked like before and after. Its the same manifold.
Cleaning procedures well documented in the manual.

If your planning on upgrading your pump make sure your manifold has been restored first.

The threaded portion of the manifold is designed to allow air to spiral around the outside of the set screws and maintain the precise length and size of air passage required for an efficient air bearing. Page 42

Next in Line.
The Air Bearing Spindle psi requirements are less than the manifold as only a portion of this air is required for it to float properly. Approximately 50%. That means on a base ET2 only 1.5 psi ! - if your manifold is restored and functional.

The "old" air escapes as per Bruce' design out the sides of the manifold.

Richardkrebs - you must have time on your hands...

I fail to see the relevance of your comment. If you're really that interested the previous post took 40 mins - which is about how long it normally takes to down my mug of coffee with one re-heat. The intent (agenda) of all this includes awareness, interactive sharing, knowledge, learning, and "mostly" fun. I am having a blast. how bout u ? A fun start to my day now that I am not living with the bears.

Now where were we ? Something about the similarities of the ET2 VTA and a brothel ?

Chris.
Sometimes these posts can be unintentionally blunt.
re the time thing. I meant that you always seem to be prepared to spend your time researching and sharing your extensive knowledge on the ET arms. I personally have learnt much from your input, which is most appreciated.

I look forward to the brothel post!

cheers

I haven't felt this much pressure for a post since I stopped reporting to a boss (wife not included)
you guys prove once again that sex sells well even if in theory only. Now to come up with something that is pertinent, force us to look at ourselves, chuckle a bit, maybe destroy another audiophile inspired myth along the way ......and do it in a way that doesn't give cause for audiogon gods to delete it. Is such a post possible ?

project time management reporting

the previous post took another 40 mins.

First 20 mins to think it up, type it, push submit (all while being distracted by a puppy that seems to want to chew my leg leg off if he doesn't get 100 % attention)

another 20 mins for the system to return a successful post message. maybe some system maintenance ? maybe a little bit of audiophile exaggeration.