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Eminent Technology ET-2 Tonearm Owners


Where are you? What mods have you done ?

I have been using these ET2's for over 9 years now.
I am still figuring them out and learning from them. They can be modified in so many ways. Bruce Thigpen laid down the GENIUS behind this tonearm over 20 years ago. Some of you have owned them for over 20 years !

Tell us your secrets.

New owners – what questions do you have ?

We may even be able to coax Bruce to post here. :^)

There are so many modifications that can be done.

Dressing of the wire with this arm is critical to get optimum sonics along with proper counterweight setup.

Let me start it off.

Please tell us what you have found to be the best wire for the ET-2 tonearm ? One that is pliable/doesn’t crink or curl. Whats the best way of dressing it so it doesn’t impact the arm. Through the spindle - Over the manifold - Below manifold ? What have you come up with ?
ct0517
dover
2,296 posts
 
Hi Chris, thanks for the complement. Yes I do try to be flexible. I am contemplating a post grad course in pseudo science at the Massachusetts Institute of Technology. This may help me comprehend some of the recent posts on the forum.
john47
50 posts
 
"I am contemplating a post grad course in pseudo science"

So you've already graduated/excelled in pseudo science.
richardkrebs
427 posts
 
Ketchup
Yes agree, I would use a rotary table which we now have. But is it really a big deal if you don't change carts often. Critical in any design would be rigidity once set.
dover
2,296 posts
 
Richardkrebs
Thou doth protest too much, methinks
About what exactly.
You raised the issue of bearing stability and the placement of magnets. The mass you have added to the bearing tube destabilizes the air bearing. My question to you as to whether you have measured the reduction in dynamic stiffness in the air bearing as a consequence of your modification and how you intend to remedy this remains unanswered. You encourage people to try your modifications. These modifications could damage expensive cartridges and records. Are you inferring that these concerns about your modifications should not be raised.
richardkrebs
427 posts
 
Dover
Adding mass to the spindle helps to stabilize it.
To repeat, for a given resonant system, extra mass lowers the resonant frequency and reduces the amplitude of this resonance. This is F=ma again. Force the same, Mass up, means acceleration must go down.

I agree that adding too much mass is potentially a problem. Where we disagree is at what point this extra mass becomes a problem. Pivoted arms, as seen by the cantilever, have high effective mass due to the head shell offset. Yet nobody seems to worry about this. I would also suggest that anti skate is significantly more dileterious to the cartridges health.

Placement of magnets..... Below the bearings natural resonant frequency, it is effectively loose, above it is nearly rigid.
So the thought experiment is where is it best to place a restriction to movement which creates a pivot point in order to minimize unwanted movement of the wand. If the mag is placed wand end, the bearing clearance allows wand movement at frequencies below natural resonance but not as much as when the mag is placed at the counterweight end. This is not a bearing stability issue, it is just optimizing the bearing geometery. Like I said this the same principle employed with inverted bearings in TTs.
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