Eminent Technology ET-2 Tonearm Owners

Pegasus
Sorry didn't answer your question.
Air stream grounded to the house wiring earth.

Cheers

***** ET2 THREAD - BEARING STIFFNESS STICKY DISCUSSION *******

Just so this info does not get lost here. :^)

Pegasus

Regarding the pressure compensation, it might help to use the analogy of a stiff power supply (air supply & reserve connected to manifold) with a few local supplies (local pressure zones around air capillary openings to the bearing) coupled with high series resistance (capillaries). As current (air flow) drops on one of the sub-supplies, the voltage (air pressure) rises - kind of a passive feedback!
Regarding the usually alluded inherent "stiffness" of mechanical bearings including unipivots, it's worth to consider the following thought:
No material is stiff, everything is more or less elastic. (With some unique properties subsummized in the poetic word "character", importantly damping, and including speed of transmission). Reduce pressure area, and elasticity increases. This affects resonance frequency inherent in any elasticity / mass combo. *Point* coupling as in a unipivot or a spike point, looked at on an "atomic level", is in no way making the coupling stiff, it's the opposite. The surfaces meet in kind of a balanced force & elasticity state, a bit like a jelly ball swimming in water, to put it to the extreme. You don't get steel more elastic than with a perfectly pointed unipivot interface. Then think "it" as an elongated point and you see something like a short subminiature "string" at the end of the point - quite elastic, like a very small piece of microscopic harpsichord string. "Flatter" points like balls have much less of this, and make stiffer bearings - that depend more on extremely complex polishing processes. Some arms use the tip of a roller pen, quite clever!
The whole "argument" (rather a mythical marketing image?) of the "mechanical diode" is moot. Point coupling shurely does "something" (as everything we do does) but shurely it is not "stiff coupling" or magic diode processes. It might eliminate eg. multi-point rattling by a multitude of low pressure indefinite points, eliminating noises of "buzzing paper on a comb"-effects, tingling in metal-to-metal sonority.
And... air bearings are at the total other end of the scale!

.

That's what Bruce tells us since a long time.

Yes for a long time page 3 of the ET2 manual.

The large surface of the air bearing uses some of the tightest tolerances in tonearm manufacturing today, and is much more rigid at audio frequencies than metal bearings"

what imagery and a way of expressing things clearly.

a bit like a jelly ball swimming in water, to put it to the extreme.

:^)

Now regarding this statement .......

As current (air flow) drops on one of the sub-supplies, the voltage (air pressure) rises - kind of a passive feedback!

An observation.
When I had my ET 2.0 HP and and ET 2.5 HP both on the same table I switched their air hoses back and forth. With the supply source remaining at a constant 19 PSI, it was interesting to watch the PSI gauge go up by a few PSI when hooked up to the ET 2.0 (into the 20's) and likewise to watch the gauge go back down by a few PSI to 19 with the larger lunged 2.5. Audiogon'r Ketchup has presented graphs here showing similar information.

Relevant info from the Oct 29 Post Sticky.

CT0517
If we use my ET 2.5 as an example that you set up specifically for 19 psi which is your optimum design setting for your tonearm. A continuous 19 psi air flow is sent in. Can we assume the spindle uses all 19 psi to work optimally (or is it a percentage of this amount)

Bruce
The manifold is optimized for the design pressure, the pressure at the surface of the spindle is a percentage of the inlet measurement, this is by design. The ET2 uses roughly half of the air to allow the spindle to work properly ? The supporting force is the surface area of the bearing times the pressure at the surface of the bearing

ME
So allowing air to escape around the edges of the manifold as more is pumped in ? is this a captured air bearing system ?

Bruce
Yes it is captured.

Hi,

First time poster in this area.

Question

Anyone experiencing delays receiving arm parts from ET for their ET arms?

I have had my Sota /ET2 at The Analog Room for over 2 months. Requires a part from ET. Brian at Analog keeps calling ET and told part will arrive next week. This has continued for 2 months.

Stu

Hi Stu - welcome to the thread.

This has continued for 2 months.

With total respect to the relationship with your dealer;
based on 2 months of waiting I personally would be inclined to demand better status information from the dealer; in order to satisfy you they would in turn need to demand better status info from ET.

An alternative is to contact Bruce directly.

brucet(at)eminent-tech(dot)com

Let us know how you make out.

Cheers Chris

*** YELLOW STICKY FOR ET2 THREAD MARK - VTA ***

I want to thank the recent private exchanges with Banquo363 for inspiring this post to be known hereafter as the Brothel Post :^)

Why does the action of my ET2 VTA, resemble me Coming Out Of A Brothel at 2:00 am ?

Has your ET2 VTA lost its MOJO ?

The post is broken down into three parts.

PART ONE - Recognizing the problem. .
PART TWO - How does this problem come about
PART THREE - Solution/Fixes

I learned quite a bit during the preparation of this post which took about 6 full coffee sessions to prepare. It started out as a big dump of info which was slowly reduced to what is here. If any of this post helps even one ET2'er it will have been worth it to me.

So Grab a Coffee/Tea or depending on your time zone - a drink ?

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PART ONE - Recognizing the problem

***Note:The pictures in this thread are anonymous, real and have not been doctored***

The repeated message on this thread has been one of not torquing the ET2 bolts too rigid, most recently by Pegasus and yet once again by Frogman who I believe first mentioned it. I also endorse this. I have learned the hard way about too much torquing and am very "aware" whenever I torque a ET2 bolt.

As promised lets get right to the dirty little secret. Does the action of your ET2 VTA resemble you spending too much time at the brothel ?

Disclaimer/warning - the pics you are about to see show very real ET2 abuse. View at your own discretion.

The Dirty Little Secret

The pic has been oriented "horizontally" to keep with the theme of the post. Plus it highlights the detail better - don't you think ?

In the picture can be seen, imo, some of the genius of Bruce Thigpen. I don't know about you but when I look at this picture I am a little stunned with awe. It is SO out of the box thinking. Well behold the secret behind the patented VTA ET2 mechanism. Kind of looks to me like something designed to work on the Mars Lunar project ?

For ET2'ers that know about this ET2 VTA, what is seen in this picture is plain and simply, "A relationship gone very very bad between Mrs. VTA Block and Mr. Post (aka) "Mr. Worm Gear." :^) Are the brothel similarities becoming a little clearer ?

When you ride a train you assume that the tracks the train runs on are in good order and will get you where you're going without incident. How many here were/are aware that the tracked/ridged worm gear Stainless Steel horizontal post, rides on similar tracks/ridges inside the actual VTA block's RACK OF TEETH like a train? They need to be "in the groove" with one another.

Notice in the pic how the "RACK OF TEETH" are wore out. See the bald spots? How do you expect the worm gear to track that properly? This particular one was tightened down so tight that the VTA block teeth material was imbedded onto the SS post itself and the VTA block was stressed to the point of having a chunk taken out of it. You don't believe me?

Here have a look... again at your discretion

The picture is a result of uneven VTA bolt torquing and locking down "rigidly" the VTA mechanism. An extreme case of way too much torquing.What good is a patented VTA system unique among tonearms if the ET2 has lost its VTA MOJO ? The good thing is it doesn't have to end up like this. Hopefully this post sheds some light and will prevent this from happening. We've seen the problem. Can it be fixed and avoided altogether? To find the answer imo, we need to look at ourselves and go back into the past a little. After all they say the best way to see the future ...is to study the past....

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PART TWO - How does this problem come about. Reheat Coffee/Tea ? I like my Black Coffee Piping hot.

In the beginning....:^)

When we brought the ET2 home its VTA block was attached to the manifold housing already; with the four bolts torqued CORRECTLY from the factory if it was new. Now as a NEW owner of this tonearm (whether it is NEW or USED) once we got the base plate mounted and the Pillar Post on, I remember just attaching the arm without much other thought and the leveling process starts in earnest - 100 % of the effort went into leveling it. The excitement of getting it up and running, playing my records while the tonearm floated on air is just too great a feeling of "Giddy" to get over. Remember the thought of visiting a brothel for the first time ? Was it the same feeling of Giddy ? If it is, you are really old, like me.

Now I just want to reiterate, that you can't be blamed for mounting it right away on the Post Pillar. I mean this tonearm in person doesn't look like anything else you have ever owned. Some friends that have seen it in person think its scary looking; imagine that. They have told me they find it intimidating, and say it looks like it belongs in the military as a weapon....seriously.
If Bruce wasn't based in Florida you may also think it came from Switzerland. Well what if you buy a Swiss watch; how do you tell if all is good ? I'm sure Pegasus can tell us much much better than I can. I can only think to ask a watch pro to look under the cover, is one way.... The same needs to be done here. Look under the cover. More on this in a bit.

First a short true story. Born and raised in Toronto if you research or talk to people, it is known worldwide as a nice, clean, cosmopolitan but conservative city. Some have called Toronto a smaller version New York run by the Swiss. Former Mayor notwithstanding. Now there was a time however, and unfortunately I was only 10,11, 12 ? at the time, that you could walk downtown Yonge Street, and you would see plenty of doors cracked open just enough showing the internals of brothels inside with scantily clad women sprawled across couches waiting for customers. I remember finding it odd at the time that so many of the guys they spoke to were called "John". What a coincidence I thought. I can still see them today ! No not the John's.... the scantily clad women ! Its like your old playboy, hustler and other such magazines.The women never age.... Now the really unfortunate part is that by the time I was old enough to enter within these doors - the crackdown had occurred and all was wiped clean... :^(

ok - BACK ON the VTA TRACK ............

If you are a long time ET2 Owner or a New Owner that just brought home a USED ET2.

New Owner Used ET2 - Don't mount the VTA Block/Manifold assembly on the post Pillar just yet. More Patience is required. You need to have a look at the VTA block's internals and assess them first. You see along with the ET2, you also happened to pick up some baggage called the relationship between Mrs. VTA block and Mr. Worm Gear" that we just saw a picture of above. If you intend to use the VTA then you need to determine if this relationship is a happy one or not. The one in the pic above was obviously NOT.

Existing owners or if your ET2 is already assembled and you are having issues with the VTA.

Remove your cartridge and lead weights. Remove the Main arm assembly from the Pillar Post. Undo the four bolts that hold the VTA Block in Place and pull out the VTA Block that contains the Post assembly - What do you see inside ? Have a look at the VTA treads (RACK OF TEETH) inside. Do they look clean with no tread fragments on the worm gear. And do the teeth/tracks/ridges look even, sharp and well defined. If Yes - this is an indicator of proper torquing. The VTA bolts are torqued at the factory. But we all know we get curious and all of us - "ALL" - have re torqued the VTA block bolts - each one,probably different than the other three. The ridges/treads get worn unevenly when u do this. The VTA Block mechanism tells a very important story in a used purchase. The history of your arm.

Was it owned by a VTA Virgin or a VTA Whore ?

IF YOU HAVE AT ANY TIME RE-TORQUED ANY VTA BLOCK BOLT WITH THE TONEARM MOUNTED ON THE TABLE- YOU HAVE THROWN OUT YOUR ALIGNMENT.
Torquing and adjustment of the VTA block needs to be done - "OFF THE TABLE"

Sorry for yelling on this last point - but it is very important.

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PART THREE - Solution/Fixes

If you indeed discover that your ET2 looks sort of like the one in the pic, All is not lost. You see unlike real life where pills are needed if you happen to lose control of your tool, here in Vinyl land you can actually have a new VTA block sent to you so all is good again. You can again have the joy of the patented ET2 VTA Brothel and enjoy your music.

FIRST OPTION - GET A NEW VTA Block

Send your Manifold housing, VTA Block and Pillar Post to Bruce. He will machine a new VTA Block for you. This will result in restored operation, and now with an owner that has real knowledge based on past experience. I would also recommend anyone who is upgrading the Manifold to HP - ask Bruce to check your VTA block assembly as well so he can assess if he needs to replace it. Each VTA block is unique (one of kind) as far as how it joins to the manifold assembly. IMO the price shown on Bruce' site for the parts and machining that contains a new VTA block and SS Horizontal Post gear inside is an example of an manufacturer who doesn't gouge audiophiles. Now a note : If you are buying used ask the seller to check the VTA Block condition for you. Otherwise assume you may need to purchase another VTA block if you want to use the VTA.

SECOND OPTION - RESTORE YOUR VTA BLOCK TO FACTORY SETTINGS

If your VTA Block is still in Good Shape but you feel you have "messed with it" and want to set it up to the factory settings here are the instructions direct from Bruce Thigpen.

From Bruce: (word for word)

My first rule would be to use the short end of the Allen wrench as the lever for torquing any screws on the ET-2. The short lever arm will limit the applied torque.

For the two bearing blocks that mesh the pinion to the rack in the arc block we first adjust the blocks so that they are parallel to the manifold housing with a .060 -.090 gap between the bearing block and the back adjacent surfaces on the manifold housing.

The friction between the manifold housing and the arc block define the feel of the VTA mechanism lever action. We want this to offer some resistance, but not too much when a VTA adjustment is attempted. Turn the 4/40 x 3/4 bearing block screws so that some friction is encountered when adjusting VTA but not so much that the VTA mechanism locks up. We would not attempt this adjustment with the tonearm installed on a turntable.

The main failures we see with the arc blocks are:

1.The threaded insert on back surface of the arc block is cracked due to over torquing of 8-32 stainless steel button head post mounting screw.

2.The bearing blocks on either side of the arc block which support the pinion gear are over torqued which crushes the pinion into the rack and binds the mechanism, if a VTA change is attempted with over torqued bearing blocks the pinion turns and the rack does not move, stripping the teeth on the rack.