Eminent Technology ET-2 Tonearm Owners

apb3rd formally apbiii

For the record I am resurrecting a TNT / ET 2.0 high pressure setup after a 5 yr delay after a move.

I read your post on resurrecting your TNT. (And about your most interesting motor control approach too!)
I use such a valve, but it needs an "overhead" of pressure you don’t have with 2.7 psi. I used to "stack" two original Takatuki pumps, this is possible because their housing is airtight. Means hot glueing a short piece of silicone tube onto the input of the second pump. (Connecting the other end to the output of the first pump)
With two pumps you get about 0.4 Bar which is good enough in the sense of achieving quite an improvement over your present pressure.
There are two diameters of the high pressure manifold, one for the original bearing tube diameter, one for the considerable thicker bearing tube which is the modification to the ET 2.5.
Depending on your cartridge, the ET 2.5 may a bit on the heavy side (there are posts on the experiences with both).
I think the Genesis 1000 is among the MCs with a softer suspension. So staying with the original diameter - but changing to the high pressure bearing would be optimal, because:
The high pressure version is manufactured to an - even! - closer tolerance and therefore bleeds off less air. (We talk about +/- 5um...  and less for the high pressure manifold !).
So the high pressure manifold improves sound by itself and also increases the pressure you get with an existing pump. I think Bruce used to optimize the air film thickness for certain pressures for his high pressure manifolds.

I am will be using the Jung pump so I don't have a problem with having enough pressure.  I'm currently existing with the original Wissa.  Before my move I ran it off a shop compressor at about 17psi.  It was about 100' away so I did not use a surge tank.  For this setup I will build one.

As I understand, there were three spindles available, the original low pressure, a high pressure small tube and the large tube.  I have  the small high pressure version.

I have a Control Air, more or less, low pressure series 700 regulator which I will use with a Control Air miniature 800 series that has a flow rate of 5 scfm which is much more than we need but much less than your typical regulator.  This should give me a little better regulation.  I think the proper place for the bleed valve is downstream of the regulator.  I may try another one between the regulators but that is probably overkill.

One side of the stand for the vta adjustment is striped and I may upgrade to the aluminum one if it is still available.  It still works but I can only approach  level from one direction.

If I recall correctly the compliance of the alpha is 15x10-6 so that puts slightly  the transition from low to medium compliance so the al tube should match pretty well. 

In the not two far distant future  I plan to add a 2nd 16# lead/acrylic/cork platter to the TNT which will require raising the ET 2 1.5 inches.  That will involve adding a longer base screw.

I will also probably splurge and get the Sota Eclipse package.

I think too, that the smaller ET2  alu tubewill fit that cartridge nicely, specially when it's the high pressure model.
My B&O MMC2 OTOH works very well too even with the heavier ET 2.5  manifold/tube and the magnesium arm tube - the arm is quite tolerant if you are careful with the counterweight springs, damping etc.
The WISA pump was not original, it came with the tank as a third party ET2 "tweak". The WISA pump (at least mine) delivered less pressure and more pulses - it is a single membrane pump. And yes the 50 Hz pulses subtly "made something with the bass" - ie. more prominences in that range but not an increase of transparency...
The original pump was (is?) a rel. low noise Takatsuki double membrane pump.
Adding the surge tank is an audible and easy improvement.
In my setup increasing the pressure is improving the sound considerably up to ca. 0.5 Bar above which I found it difficult to hear as an improvement.
There is an increase of turbulent air exiting the manifold with increasing pressure, it might be a sort of trade-off of increasing bearing "stiffness" vs. air noise.
 

I stand corrected.  I do have the Takatsuki app6ga which only has the model number and no manufacturer.  I always thought it was by Wisa.  I finally got the Jun  Air pump working (actually my version is by Werther international, P15-TC1) and it works well but it cycles and produces a loud POP as it switches. I will try a slow start module and see if that helps. If that fails I may need to set up a large tank and either leave it on or suffer the wait each time I go to use it.  It is pretty quiet but I may yet move it out of the room. 

Next step is to re plumb the air supply and include a surge tank. Not expecting much, if any gain, as the compressor already has a small tank.