Eminent Technology ET-2 Tonearm Owners

Interesting “facts discussion” about linear vs. radial tonearms, most have probably read it:
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1266367593&openfrom&1&4&&st100
Sadly mostly boring (ie. repeated, but skewed arguments)… but some interesting points. A main point is the quotation of a High Performance Audio Review test in the 80's measuring much higher actual sideforces and deflection of the cantilever on a SAEC radial tonearm vs. an air bearing arm.
The reaction of the (radial) “experts”: Hilarious, ridiculous! The facts don't follow their invented orthodox belief, so the facts must be wrong! The reaction of other more pragmatic non scientifical audiophiles: This is only one situation, we must collect other… (measurements).
Experimental science means, one well set up experiment with a non expected measured outcome can expose any pre-existing contrary hypothesis as wrong. In this case the “excessive side-forces”. But what am I as a humble pragmatic thinker compared to the pope(s)?
Over most of the thread the effect of mass and bearing friction on a cantilever are confounded, and bearing stick vs. bearing friction isn't even mentioned. Neither are there attempts to define the magnitude of differences of (horizontal) friction of radial vs. air bearing arms. I think/suspect that even with the “lever advantage” the best radial arm may just quite cope with an air bearing. Horizontally that is. The rest is wrong thinking about the optimal horizontal mass aka. the desired horizontal resonance frequency – for best bass reproduction with lowest phase shift. The dynamic side forces on a cantilever are simply a result of friction (mostly non existant in an air bearing) and mass. Ie. they correlate with the horizontal resonance frequency – and are taking part in a compromise, where the sonic optimum lays much lower than audiophile orthodoxy.

Hi
I am new here and in need of some tips
I have a ET2 that Im trying to upgrade to a 2.5
but have problem running it on 7.5 psi. It was marked mpm
I have a felling that is a bit clogged. What is the min working pressure for a mpm?
Any way to clean out the hole think there can be a bit of oil in them. This have a NOS upgrade kit came in plastikk bag and was a bit greasy. Have clean it a bit with alcohol
Got it to a point where it works "just" 95% of the time.
outer and inner section can some time be problematic.

I have Wisa 300 pump makes to much to noisy and need to be move that is most likely to bring the 95 down to 0.
there will be a lose in pressure even in a stiff tube over 30 feet.

But before I work my way true all the pumps I need to be sure that I have a working 2.5

any tip how to figure out this one

With regards

Styrk

hi Styrk,

I believe I saw the auction for the manifold you are referring to. The seller told me about the 'mpm' and since I never hear of that I emailed Bruce about it.

Here's what he wrote back:

"The initials on the 2.5 manifold are actually HPM and it stands for high pressure manifold. This means the pressure range is between 5-10 PSI but it could be higher if the person who purchased it asked for one to be used with a shop compressor."

I took that to mean that there is no such thing as a 'mpm' manifold. So assume that it reads 'hpm'. I know of users who run their hpm at 19psi, so in the absence of knowledge about its history, you will want, for testing purposes, a pump that can deliver a range from 5-19psi.

A different explanation for what you are experiencing is this: the spindle that you are using is not properly matched to the manifold. Perhaps the user ordered the hpm alone, and for the auction bundled it together with the spindle s/he used with a standard pressure manifold. So, even though your pump is doing its job, the manifold/spindle combo you have is destined to fail.

The only guaranteed solution to the latter is to send your manifold back to Bruce and have him find a matching spindle. Other posters have reported ordering a hpm and that it worked fine with their existing spindle, so you could try that as well.

How do I know all this? Well I ordered a hpm last December and I have pretty much experienced every difficulty one can have. Bruce sent me a spindle last week that he thought might work (with no guarantees); it doesn't. Like yours I can get it to play a record, but it binds at various places, making for some poor sound.

Last night I wanted to test the manifold to see whether it alone was the issue. In my case, when everything is level and vtf is at 0, the arm always races down towards the inner grooves. I have to tilt the counterweight side up to prevent this--and this is when some binding occurs. For the test, what I did was put the manifold into the housing 'backwards' to see what effect that would have. The spindle now raced towards the outer grooves. That tells me there is some pressure asymmetry delivered by my manifold. Either something is clogged (unlikely since it is brand new and I've always had 3 filters in front of it) or the asymmetry is something that is addressed via a matched spindle (which I don't have). Or...?

Good luck.

Hi Styrk - welcome to the thread.
In addition to Banquo's comments pls see mine below.

I have a ET2 that Im trying to upgrade to a 2.5
but have problem running it on 7.5 psi. It was marked mpm

Firstly pls note that a ET 2.5 and HPM (High Pressure Manifold) are two different separate things. There are low pressure 2.5's out there. Banquo has one of them.

To upgrade to a 2.5 from a 2.0 (high or low pressure manifold) means sending your 2.0 manifold, its housing and 2.0 spindle to Bruce. He will return to you a 2.5 manifold and housing and 2.5 spindle. The VTA Block should not be separated from the housing. This way Bruce can ensure it works properly.

The 2.5 spindle is a bigger diameter and the hole in the manifold housing made bigger to accommodate the larger manifold and spindle diameter.

The larger 2.5 tube resonates at a lower frequency and a better design overall for low compliance cartridges. A better design can lead to more potential. But the 2.0 works with low compliance cartridges as well. Just requires more tweaking.

Any way to clean out the hole think there can be a bit of oil in them. This have a NOS upgrade kit came in plastikk bag and was a bit greasy. Have clean it a bit with alcohol

I have a feeling that is a bit clogged. What is the min working pressure for a mpm?

If it is a NOS upgrade kit the capillaries should be clean ?

See the maintenance cleaning procedures in the manual. You can start with isopropyl and a toothbrush.
There should be no oil in there. There may be some grease on the exterior of the rings for a smooth fitting.

Assuming MPM is as Banquo said from Bruce' note, a High Pressure Manifold ?

"Banquo363 - The initials on the 2.5 manifold are actually HPM and it stands for high pressure manifold. This means the pressure range is between 5-10 PSI but it could be higher if the person who purchased it asked for one to be used with a shop compressor."

I have said this before here. The best way IMO to find out what PSI your manifold was designed for by Bruce, if you bought a used one ....
First clean it out and make sure the capillaries are not clogged.
Make sure the pump/s is actually producing the expected PSI at the arm "NOT" at the pump.
Then start raising the PSI till it works well. Go one to 2 psi above.

Working well means all the way through but especially the last track when everything is level.
Use gravity to level the Spindle.

Does this make it clearer ? Ask any questions, we are here to help. We all started where you are now.

Welcome to the fun......

Banquo363.
Last night I wanted to test the manifold to see whether it alone was the issue. In my case, when everything is level and vtf is at 0, the arm always races down towards the inner grooves. I have to tilt the counterweight side up to prevent this--and this is when some binding occurs. For the test, what I did was put the manifold into the housing 'backwards' to see what effect that would have. The spindle now raced towards the outer grooves.

8^0

Be interested in Bruce' reply to this one .....

08-26-15: Pegasus
Interesting “facts discussion” about linear vs. radial tonearms, most have probably read it:

Are linear tracking arms better than pivoted arms?

Sadly mostly boring (ie. repeated, but skewed arguments)… but some interesting points.

Hi Pegasus - nice to hear from you again.

Re: Pivot versus Linear discussion.

IMO - Everyone that has been in this audio hobby for any length of time knows its all a "set up" game - vinyl. My personal experiences have been a good pivot arm set up well, will out perform a below average set up of an ET2. So in my opinion we need to be very careful with reviews and experiments, as they are based on that person's setup only and it doesn't represent other set ups. Rooms are different as is the gear right down to the TT setup and condition of the cartridige. No two are alike . So I say for all these professional reviewers who know this already.

THEY HAVE ALL SOLD A BIT OF THEIR AUDIO SOUL FOR SOME AUDIO DOUGH. ....heh heh heh ...

So its an individual basis thing just like all our systems. With that the better design always has the most potential. And potential for this audio hobby is defined to me as more ROPE for The Vinyl Hangman :^)

Still to this very day, FOR ME, Bruce Thigpen said it best. Re: Pivot Arms.

Page 46....... ET2 Manual

********************************************************
There is a force component (vector) that is directed toward the center of the record. It results from the stylus drag force vector not falling in line with the pivot point of the arm. This force pulls the tonearm inward and the stylus can be observed as bending outward.

THIS FORCE AND THE RESULTING BENDING CAN BE DEMONSTRATED BY CONNECTING A RUBBER BAND TO A PIVOTED ARM AROUND THE CARTRIDGE BODY AND PULLING IT STRAIGHT AHEAD (AWAY) FROM THE TONEARM. NOTE: THE MOTION OF THE TONEARM IS INWARD AND RESULTS IN THE BENDING OF THE RUBBER BAND (CANTILEVER).

*******************************************************

You guys with pivot arms should try it. put a rubber band around the cartridge on your pivot arm and pull. (Hey - not responsible for any beheaded styluses). Been there, done that. Watch and .......feel...... what happens. You will never again doubt why Antiskate is needed on a pivot arm.