I went down to Palmer street today to see the man himself. I was a bit confused about what upgrades would be best for my ET-2 running 18 psi with an 8.5 gram medium-compliance cartridge. I must say, what a great guy he is. As we stood in the ET-2 parts room, he said without hesitation the aluminum joint is a significant and cost effective upgrade. As I gazed into the two boxes containing ET-2 and ET-2.5 bearing spindles I asked what about upgrading to the 2.5 manifold and spindle? He replied that since I’m running 18 psi from a shop compressor I would not notice a difference, On the other hand, If I were using a low pressure pump, it would be a nice upgrade with noticeable improvements.
In the post above I stand corrected. In that post i stated ". . . all 14 manifold air orifices . . ." Bruce told me that there are no orifices, those are 14 screw-in plugs. I then ask how does the compressed air go from the manifold housing through the manifold in order to float the spindle bearing? His answer floored me and its difficult to describe without a diagram as Bruce scratched out on a piece of paper for me, but I will try. He said that an air bearing works best if a small column of air flows some distance from the manifold housing to the area between the inside of the manifold and the spindle bearing. With just an orifice, the distance would only be a couple of millimeters. I ask how is that done when it appears that each threaded hole is totally plugged with a stainless-steel set screw? The way he does it is that he machines a small amount of material from the protruding edge of the threads in each hole in the manifold. That way a metered amount of air follows a spiral path around the threads between the threaded plug and threads in the manifold hole. The distance around the threads creates the distance needed to enhance the air flow into the area between the manifold and spindle bearing. Obviously it works!
I learned more in that 20 minutes with Bruce about the ET-2 than I learned on my own in the last 15 years of ET-2 ownership. There is so much more to the engineering of the ET-2 than I had ever imagined. I am now totally convinced, that the ET-2/2.5 is by far the most highly engineered and best linear-tracking tonearm ever developed. And that include those very expensive European offerings that gleam with gold plated cladding. If you have an ET-2/2.5 keep it - you have the best. Mine has been three turntables and my guess is that it will be on a fourth one day. Turntables come and go but the ET-2 stays.
I have to go back to Palmer Street next week to pick up my aluminum wand joint since this batch were not yet out of production as of today. When I go back, I think I'll ask him about the TRW-17. 115db at1Hz! I would really like to hear (or feel) that!