Eminent Technology ET-2 Tonearm Owners

Chris.

You have now given us all another area to pine over. Humidity.....thanks a lot! :-)

I don't think that your test is quite representative of what I was suggesting, since you are disabling one regulator but leaving its body in circuit. If their is any instability in the regulator it could be caused by the its structure, since the air flow path is convoluted. For example the water separator function is achieved by creating a vortex in the bowl.

I will have a play this weekend where I move the regulator close to the arm, making the adjustment for line losses. This will keep the arm pressure the same.
I will use exactly the same hose and length so the only variable will be the reg position.

BTW, I have a pressure gauge very close to the arm, it reads in bar. Setting the pressure by ear results in a reading of 1.25 bar which is a little over 18 psi, not the 17 psi I mentioned earlier. That said how accurate are the gauges we are using anyway?

cheers.

don't think that your test is quite representative of what I was suggesting, since you are disabling one regulator but leaving its body in circuit. If their is any instability in the regulator it could be caused by the its structure, since the air flow path is convoluted. For example the water separator function is achieved by creating a vortex in the bowl.

this is true Richard. not the best example - I could unplug both ends and just use a coupler.

That said how accurate are the gauges we are using anyway?

Even if these devices were perfect we know that no two records are identical.
Always trust your own ears. Use measurement devices. PSI gauges, alignment devices, VTF scales to just get into the ball park. Fine tune with your ears.

Chris.

Even if you use a joiner, you will still be removing one regulator from the air circuit so it will not be a true AB test.

Yep agree, measurements only take you so far.
We don't listen to numbers.

Ok
Since I cooked dinner tonite, I got a leave pass afterwards...,

Have just finished trying the second regulator close to the arm.
There was just 3 feet of tube between it and the arm, the original configuration having 40 feet of tube. I adjusted the pressure to compensate for line losses.

With the regulator close, the soundstage shrunk both in width and depth. There is a subtle veil over the sound with attack and decay diminished.
The model of regulator I use is. Norgren B07-201-A1KG.
Looks like a pretty standard unit and appears similar to the photos posted here by various owners.

After an hour of going back and forth to confirm my findings, I couldn't wait to settle back to the original layout.......
Compressor with built in regulator- 4 ft PVC tube- needle valve bleed off- second regulator- 40 ft PVC tube- pressure gauge- arm.

The Norgren regulator does something to the air flow that the arm doesn't like. Having 40 ft of tube mitigates this.
I would be curious to read findings from others where a significant length of soft PVC tube was used between the reg and arm vs a short length of the same tube.

For my setup the long tube was clearly superior.

thanks for sharing impressions Richard.

With the regulator close, the soundstage shrunk both in width and depth. There is a subtle veil over the sound with attack and decay diminished.

Just recollecting.
When I was experimenting with PSI years ago, these are the same symptoms I encountered, when there was too much psi for the manifold and it caused the spindle to start resonating - affecting the cartridge.

So out of pure curiosity my questions would be:

1)What PSI is your manifold designed for ?
2)Did you try different records that required different VTA's during the comparison ?
3)Did you try it with and without the damping trough.

If you chose to compare again - I would go with a longer 6 foot section of tube to the arm and lower psi.

Maybe I misunderstood what you were trying to compare so let me confirm.
You went from this:

pump--------40 feet hose-----tonearm manifold

to this

pump--------40 feet hose---regulator -----3 feet hose ---- tonearm manifold.

If my crude flow chart is correct - you have imo introduced a more consistent air delivery into the manifold. The reason being alot can happen (changes)to the air in the 40 foot run.
Here is something to think about. Sometimes when we introduce something that in theory should work better, for reasons described above, it ends up sounding worse.

Well - what if better more consistent air delivery exposed a set up issue (i.e. too much psi)

Again just thinking out loud - remote troubleshooting is difficult with a one sentence description.

I do think its worth noting here again if anyone should pick up a used ET2 or ET2.5; and they do not know what PSI the manifold was set up for. One way to find out - put an old record on and start lowering pressure. When it starts skipping raise a few PSI. Fine tune final PSI by ear.

ymmv - water deposits from the air could have clogged the capillaries requiring more PSI to even work ! The manifolds are easily cleaned - instructions in the manual. If I bought an Et2 from an unknown source I would clean them before setup.

Cheers