Eminent Technology ET-2 Tonearm Owners

All true, pegasus. Thanks for sharing.

Dave

Hi Pegasus

To have the arm helping leveling, the arm wiring is critical and needs to be thin and very elastic, ideally left/right separated with optimal wire looms.

You mentioned this type of wiring setup previously. I can envision it but would like to see a picture of it. Feel free to send a picture to me if you like at

bcpguy (at) bell (dot) net

and I can make the picture available to the others.

Another option is to have a straight shot all 4 wires exiting the armtube, which then go to the phono stage direct. On their way there, leaving the armtube are 4 separate strands which are placed in a happy face loop***.

This eliminates binding. Binding is the ET2’s kryptonite. The 4 wires attach to the nearby platform your phono stage rests on (around the mid travel point for the spindle). From there the wires are joined to the phono stage. A picture of this can be seen on my virtual system page - Just click on the Runner.

***
My daughters Bengal kitty loves my rooms, and I love her company, but her curiousness is fraught with danger. In room two it is the naked Quad Electrostats. In my main room, one evening as I placed a record on and sat in my chair, I could see shadows behind the turntable. Indeed a tail was waving. I looked over the table and there she was behind - eyeing both the spinning Platine thread and happy face 4 naked wire loop wiring - deciding I think which to pounce on first. My heart beat reached running levels in about 2 seconds.


Specifically to lateral forces - the ET2 versus conventional tonearms. As has been discussed here before.

"the lateral forces are .1 gm. compared to .2 gm on a conventional arm. These figures apply if you do not play records that are not severely out of round. If you like to play severely eccentric records, ones with run out greater than 1/8 ", then we suggest you use a low mass pivot arm"

Taken from Bruce’ measurements and published in the ET 2 manual - Page 47 - Antiskating and Frequency Modulation Distortion Section.

Pegasus
I doubt that in the 80’s all too many ET2s were set up correctly, thus leading to the mythos that straight tracker have a "problem in the bass".

I agree and I am pretty sure all first time ET2 owners of the 80’s, were previous pivot arm owners, who were fascinated with the ET2 arm design and function, but quickly became frustrated with incorrect setup from not reading the manual. The biggest technical error imo - leaving all the weights on the I beam, and simply moving them inward closer to the air bearing for more VTF - like is habit with most pivot arms. This does not give you the highest vertical inertia needed for the best bass.

Cheers

Hi Chris! I tried making photographs of the wiring - but the spot is too dark, and the flashlight messes things up – but I'll try again.
- It's funny you mention that (even) increasing vertical mass by minimizing & shifting the counterweight out on the I-beam improves bass. Ie. moving the vertical resonance down from a frequency above 12 Hz in many cases. Because "too low" resonance is much more a problem with vertical resonance, not lateral, as LP rumble is mainly a vertical problem – and you hear even there that lower is better. I don't doubt this!
How much less of a problem is a really high *lateral* mass within a certain safety range (not below 2-3Hz resonance)!
(Except that down there is a problem with magnetic flux with some MM and/or MI? cartridges I suspect and found - not with MC.)
- I think the quote of "lateral forces are .1 gm. compared to .2 gm on a conventional arm" refers to the forces exerted by wiring stiffness and skating forces, not to off-levelness of the arm.
If one doesn't want to exceed 0.2g lateral force one needs to set up the arm to a level precision of less than 0.2mm over a 100mm travel! It's no problem to level the arm as such - but the wire may exert a "correcting" force for an off-level arm, and changes this sideways force at a different place than where it was level. A bit of a case of luck with the original cabling, or wandering setup of the turntable base.
- The increased FM modulation with radial tracking goes back to the dynamically varying friction which dynamically varies skating force with modulation, different radius, different pressing / vinyl surface, and different aerosol deposits on the vinyl. With the straightline trackers are always tangential except LF resonance, off-levelness or other reasons for a slightly off-tangential cantilever. But this error angle is always much lower than with conventional radial arms with strong offset angles. 
- This absolute offset angle is really much lower with the Thales arms, specially with the newest, the Thales Easy.

Hi Pegasus - I think I missed my calling. I am amazed by the physics that is happening with my turntable setup. Here I went, and became a consultant involved in a field, Business/IT, that was so new and exciting some 35-40 years ago. Who knew back then that it would be ever and always changing; so much so, that if you did not stay current, even for a few years, you become obsolete very fast.
  
You can't change Physics. Many have tried. Some have even tried with the ET2.

:^0

I happen to come across this Bruce Thigpen '07 interview in a Machine Design publication. It has some nice insight into Bruce and his products.

My lifelong fascination with audio and sound reproduction resulted in the start-up of Eminent Technology in 1982. Unfortunately, 1982 was also the year the compact-disc player came along. And so it appeared that our first product, a high-end, air-bearing phonograph tonearm, wasn't going to keep the lights on indefinitely. Still, the demand for high-tech, high-end record players never disappeared entirely.

8^0

In the article Bruce gives good info on how dipole speakers work, and the reason for their bass limitations. There is also good info on how the rotary woofer works.  

Enjoy.

here is the link 

http://machinedesign.com/archive/good-vibrations-0