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 ?
128x128ct0517
Hi Tim
Congrats on the ET2.
Please let us know how you make out.
A number of folks here with many years experience with the ET2 & ET2.5 to help out if any questions.

There are also measurements on page 63 of the online manual on Bruce' website. from looking at the online diagram for the mounting hole.

1) From the middle of the spindle go out 8.258 inches (209.753) millimeters anywhere on the plinth that works for you and mark the spot.

2) Draw a straight line from the middle of spindle to this marked spot.

3) Go up 90 degrees from this line .885 inches (22.479 millimeters)

Mark the spot - that's where the mounting hole goes.

Welcome to the thread.
Cheers Chris
Thanks Chris,
I talked with Bruce today and put in an order for the missing bushing,magnesium arm,and high pressure manifold.
I will keep posting my progress.

Tim
Random Included Record Angles When they Make Records

You play a couple of records from your collection that are the same thickness. They sound different for some reason ? One might be brighter, the other a little warmer and full ?
This was not something I took much notice of many years ago with a very basic TT and tonearm. But as the TT and tonearm got better it became more noticeable.

We hear about how engineers in creating the master disc put their spin on how the records will sound. But how about the physics part of it. In addition to the final engineering differences record masters are cut with random included angles by the cutter. The angle of the cut when the record master is made.

http://www.aardvarkmastering.com/riaa.htm

from the site

Recording Groove Contour
a. Included angle 90 degrees + 5
b. Bottom radius 0.00025" max.
c. Width--Monophonic .0022"--.0032"
d. Width--Stereophonic, Instantaneous .001" min.
Minimum Inside Diameter of Recording 4 1/4"
Runout of Recording Grooves Relative to Center Hole .050" max.

Notice the record included cut angle standard that was set can be 90 degrees give or take 5 degrees....:^(

So there is no standard.

This is also captured in the ET2 manual and has been mentioned before. Bruce realized the importance of this and the reason he built into his arm VTA on the Fly that does not change parameters when used.

Vertical Tracking Angle Adjustment (VTA) - Page 51 ET2 Pt. 2 manual

"Several articles have appeared which address the area of cartridge performance. Vertical Tracking Angle (VTA) and Stylus Rake Angle (SRA). We have designed the Model 2 tonearm to optimize the vertical tracking angle of the cartridge.
The angle that the cutterhead is placed at when a record is cut results in an included angle in the final disc. This included angle must be duplicated with the reproducing stylus or distortion will result. The problem today lies in standardization of the angle by record manufacturers and corresponding standardization by cartridge manufacturers. Presently most records are cut with resulting vertical angles between 16 and 20 degrees. The average vertical angles of cartridges manufactured today is slightly higher than 22 degrees. The result of this mismatch is less than optimum performance for many cartridges."

Maybe those that use scopes should be pointing the camera - down - to the groove to try to figure out what angle has been used ?

Some ET2 owners I have talked to have locked down (tightened the screws controlling the VTA feature) to make it more rigid?

fwiw - I have sent an email to a couple record pressing plants as I am curious what determines what angle they cut at.
Is it based on temperature, record thickness, condition of stylus cutter ? Will post back what they say ...if they respond.

How important is the VTA adjustment to you ?
Great topic! VTA adjustment on the fly is, for me, THE most important feature of the ET2. I find it invaluable and use it all the time. The benefits for me have to do with fine tuning tonality, timbre, and the integration of the uppermost frequencies with the lower highs (sibilance, among other things) and the transition-range between the midrange and upper bass. I have not found (maybe simply don't care as much) dramatic changes in soundstaging due to different VTA settings as some have reported. Azimuth adjustment (also relatively easy with the ET) does make significant changes to soundstaging in my set-up.

Re the locking down of the screws that tighten the VTA feature: I feel that too much torque at ANY of the ET2's screws is a bad thing. I think the arm simply sounds better with moderate and similar torque at all the screws. I adjust the VTA adjustment screws so that the adjustment can still be made without loosening the screws; but with some effort. So, to make sure I am not stripping anything, I simply loosen the screws about a 1/4 (or less) turn, adjust, and re-tighten; just a couple of extra seconds for the procedure.
09-16-13: Ct0517
Random Included Record Angles When they Make Records
...record masters are cut with random included angles by the cutter. The angle of the cut when the record master is made.
Recording Groove Contour
a. Included angle 90 degrees + 5
b. Bottom radius 0.00025" max.
c. Width--Monophonic .0022"--.0032"
d. Width--Stereophonic, Instantaneous .001" min.
Minimum Inside Diameter of Recording 4 1/4"
Runout of Recording Grooves Relative to Center Hole .050" max.
Notice the record included cut angle standard that was set can be 90 degrees give or take 5 degrees....:^(
So there is no standard.

The angle that the cutterhead is placed at when a record is cut results in an included angle in the final disc. This included angle must be duplicated with the reproducing stylus or distortion will result.

The problem today lies in standardization of the angle by record manufacturers and corresponding standardization by cartridge manufacturers. Presently most records are cut with resulting vertical angles between 16 and 20 degrees. The average vertical angles of cartridges manufactured today is slightly higher than 22 degrees. The result of this mismatch is less than optimum performance for many cartridges."

How important is the VTA adjustment to you ?

1. The "included angle" has nothing to do with VTA. The included angle of 90 degrees is the angle between the 2 45 degree walls of the groove. ( 45+45=90 ). In theory if the cutterhead is set up with an error of say 5 degree in the "included angle" then you would possibly need to adjust azimuth.

2. One of the fundamental problems is that the cutter moves in a fixed plane, whereas the stylus moves in an arc about the cantilever pivot, and therefore all cartridges with a conventional cantilever produce distortion. The notable exceptions are the Decca London Cartridges and the original Ikeda cartridges both of which do not have cantilevers and therefore these are the only cartridges that do not have this distortion built in. I own the Ikeda and have personally set up around 20 Decca's over the years. The speed, lower distortion and lack of phase and time smear with these cartridges is superior to anything else for the reasons outlined in the 1st sentence of this paragraph.

3. Cutterhead angles are a minefield as they varied historically over the years and different cutting lathes were set up with different cutting angles. There was a standardisation of sorts in the 60's but bear in mind the US settled on 15 degrees +-5 degrees and the Europeans settled on 20 degrees +-5 degrees.
The actual cutting angle used would also depend on how the engineer sets the equipment up and that is unpredictable. Springback is a common problem when cutting and this will alter depending on the composition and quality of the lacquers used ( they are soft ). Temperature is a big factor and if the lacquers have been stored at room temperature, as opposed to the recommended cool room temperatures, then often engineers would alter the cutting angle to get a clean cut due to the changing properties of the lacquers at different temperatures.

A few points to note :

Increasing the room temperature by 5 degrees F or approx 3 degrees C will lower the tracking angle by approx 1 degree.
Increasing the tracking weight by 0.1g will result in a lowering of the tracking angle by approx 1.5 degree
A spherical stylus profile will help to reduce these distortions in points 2 & 3 above.
If you add lead mass to the ET2 and remove the decoupled counterweight, as suggested earlier in this thread, then VTA doesn't matter as the increased distortion from a tracking angle error of +-5 degrees is almost certainly significantly less than the distortions introduced by the addition of lead mass and removal of the decoupled counterweight.

For ET2 aficionados, with a conventional cartridge that uses a cantilever, the combination of tangential tracking and a spherical stylus would minimise distortions due to VTA issues. I have run the Denon 103 which although not the ultimate in transparency, produced very good timing and coherence. The EMT TSD15 with spherical tip option would be an interesting cartridge to try.