Eminent Technology ET-2 Tonearm Owners

Pegasus

My techno-intuitive thought on this is:
- The lower the resonance of the i-beam, the wider the frequency range over which the bearing/cartridge resonance can be controlled by it.
- the higher the resonance, the closer together both resonances and the more resonant interaction instead of control.

Does Bruce have the model? Or should I ask my more MATLAB-experienced son?

Pegasus
The model for the original I Beam was in part influenced by business priorities. We know this. This limitation is no longer there.  

Why don't you send your theory and questions to Bruce direct and let us know what he says ?

brucet (at) eminent-tech (dot) com

I am interested in your, John and others impressions of Bruce' Long I Beam.

Harry and I seem to be in sync.
Also, still am interested in seeing pictures of your dual path wiring setup.

Cheers Chris

@pegasus 
I agree, there is likely to be a small reduction in air pressure entering the  capillaries due deltaP across the wool and filter paper. Easily sorted by increasing the input pressure slightly.  The arm can be operated with and without the wool/paper to test its efficacy.
Much has been written in this thread  about the need for a stable air supply. It seems that the ET is very sensitive to any perturbations in the air stream. This design is simply taking this trait and seeking to ameliorate it further. Look inside the manifold at the small hole which connects the air supply to the manifold cavity. Air entering thru this hole jets across the small gap and hits the sleeve then circulates around the boundary between the manifold ID and the sleeve OD. This design change is an effort to deliver smooth air to all of the capillaries. It may not be of benefit, but I intend to find out.

Cheers 

Bruce's second run, long I-Beam delivered yesterday.  Much better fit for the weight clamp.  Sounding good. 
Cheers

Gentlemen,
I recently picked up a Van den Hul MC One Special.  Specs say static compliance is 28 micron/mN.  I don't have a clue what this means in terms of high, low or medium compliance.  Can some of you with a better engineering/physics background than I tell me which of Bruce's arm wands would be best suited to this cartridge.
Thanks,
Harry

I don't know your degree, so I don't tell you mine... ;-)Except that you will find the formulas if you feel the need.It's a rather elevated compliance in these days, not Shure-high but probably, relating to ct517 experiences, it better fits a ET 2 and not a ET 2.5, as the mass of the ET 2 is lower. However, I think it's mainly a question of the arm wand, ie. using the original alu wand.
With this cartridge it's more about experimenting with vertical inertia, starting at the lower side, starting with more counterweights close to the bearing.
You always can increase vertical inertia by trying less counterweights in the middle and then a low count at the outer end.
I suspect that still the long i-beam with counterweights out and starting with a single spring might be best, as the high compliance / low resonance frequency of the cartridge might be better controlled by an I-beam that is set to the lowest most resonance.