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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
dlcockrum's avatar
dlcockrum
2,190 posts
 
I found a rare reprint or Myles Astor's TAS review of the Motronix Acuflow Air Regulator:

http://www.whatsbestforum.com/showthread.php?5653-Linear-tracking-Turntables!/page3&highlight=motronix

Apparently, two of the people involved with designing and reviewing this unit are still involved in audio. Miles Astor, PhD is Senior Assistant Editor at Positive-Feedback Online and Marlen Mogilever, PhD, who is mentioned in the TAS article as being "of Motronix" is now the principal designer at Blueberry Hill Audio:

http://blueberryhillaudio.com/index.html

After reading the TAS article, I realize that this unit was more involved than what most of us are now using, i.e. two spring/diaphragm regulators with a surge tank in between. I wonder if we contacted one or both of them that they could/would give us enough detail to be able to reverse-engineer the Motronix unit or, at least, to mod our existing setups to duplicate the Motronix unit's functionality?

Dave
rugyboogie
199 posts
 
Received my ET package from Bruce yesterday.
Will post up pictures over the weekend of my air set up along with the ET-2.5 on my system page.
frogman
7,520 posts
 
Richard, interesting comments. Eventhough I settled on 18.5 -19 psi (at the arm) based on what my ears tell me sounds best in my system and not simply what my HP manifold was designed for, that pressure is (coincidentally?) about .5 psi above the pressure at which the check valve on my surge tank starts to release some air without fully opening. As the pressure is increased further the released air increases until the spring loaded valve opens fully (at about 20.5 psi or so AT THE SURGE TANK). Makes me wonder if the reason the arm sounds best at that pressure is not only that it is the ideal pressure for my arm, but also that the released air has a similar effect as what the Motronix accomplishes. Thoughts?
richardkrebs
427 posts
 
Frogman.

I suspect that the check valve you refer to is actually a safety relief valve. And yes it could be the same thing that I am hearing.
It may have an adjustment so you could, entirely at your own risk :-) increase its setting to see if the bleed flow could be stopped but still maintain the same pressure out of the regulator and on to the arm.
Obviously I don't know what your surge tank can take in terms of max pressure, so be careful should you decide to do this.

I read the TAS review and this could be a review of the changes I hear in my system. It is a significant jump in performance and ultra easy to do.
The dimensions given for Motronix unit would imply that any surge tank, if included, would be very small indeed. So maybe it is simply two high quality regulators with a central bleed?

It shows how sensitive the arm is to smooth air delivery. As per my earlier post, the compressor had cycled off, so the air supply was coming only from the reserve in the tank. The "noise" in the air stream could only be coming from the regulators and the associated hosing to the arm.
frogman
7,520 posts
 
Richardkrebs, yes, safety relief valve, I have always incorrectly referred to it as a check valve. Interesting proposition. My DIY PVC tank can handle the full output of my Medo compressor which although rated at 22psi can actually output close to 30psi. Dave has the same compressor and it outputs 32 psi. Prior to installing the relief valve I tried higher pressures (without controlled air bleed) but I did not like the sound which would take on an overly lean and rather tense quality. I settled on 18-19 psi for best sound. I don't think that the relief valve can be adjusted, but it would be interesting to hear what higher pressure with controlled air needing sounds like.
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