et-2 damping trough-good idea or not?

Raul - while acknowledging your experience using damping troughs with pivot arms, you need to recognize that the ET 2.0 and ET 2.5 are unlike any pivot arm, especially when discussing resonances, damping troughs and their effect on Q. They are unique among air bearing linear trackers as well.
Bruce Thigpen has done extensive measurements not just on the ET 2.0 and 2.5 but including many pivot tonearms.

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Mass from different wands changes the resonance frequency, but
has very little effect on Q, (the sharpness of a rise in response). A pivoted arm sums the vertical and horizontal resonance frequencies (because of the pivot, they are the same value). The typical rise at the resonant frequency of a pivoted arm will be 12-18dB. Audio Magazine published these figures when they tested tonearms from around 1965 until they ceased publication in 2000.

The ET-2 or 2.5 by comparison splits the resonance into two
different frequencies, one for vertical and one for horizontal, (the
math and discussion are in the tonearm manual) so they do not sum and
the rise is usually about 6-8dB which is much better. This results in a lower wow and flutter figure (about half) when you compare an ET-2 with any pivoted tonearm on the same turntable.

-brucet

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So Audio Magazine published these figures when they tested
tonearms from around 1965 until they ceased publication in 2000.
Would you or anyone else reading this - have magazines from that period that show results ?

Anyway Raul, if interested to come up to speed on the ET 2 and 2.5, a good start is with the technical section of the manual. Then I would recommend doing a search on yellow stickies in the ET 2 thread.

The decision for an ET2 owner on whether to use the trough is like having your cake and eating it to. It’s not a this or that scenario, but both. As discussed in this thread already, the oil trough paddle - is a screw design and can be raised to dis-engage and lowered to engage the oil.

It does add 18 gms so putting it on a lightly sprung table like a Linn needs to be considered. 


Cheers Chris

Great explanations from Chris as always.  The only thing that I would add re the issue of “overdamping” is that the best results for me were achieved with the “paddle” just skimming the surface of the fluid.  The paddle can be adjusted up and down and if adjusted so that it sinks too far into the fluid it literally killed transient response.  Not only were high frequencies dulled, but dynamics suffered and the music became lifeless.  

Dear @ct0517  : """  When they are put against a moving vinyl record which is not perfect, and has imperfections I discussed previously - like the ripples; these imperfections, since this is a vibration resonance activity - EXCITE - the resonances.  """

It does not matters almost all what you posted because linear tracking or pivoted tonearm designs those resonances exist and here we are not discussing if in the pivoted ones are higher or not what we are discussing is the existence of those resonances/distortions that exist in the ET tonearm and that damping helps a lot for a better overall quality performance levels.

As I said in normal use we can't overdamp a tonearm and what frogman like it or not is just what he like it or not but in some way deny the damping function and like me frogman is only an opinion and nothing more.

Btw, you do not yet post/share your experiences with your system regarding the use of that ET damping that Bruce promotes.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Raul, I realize that your audio system is perfection exemplified to the degree that only components which are themselves perfect and absolutely neutral in the truest sense of the word and completely free of distortions of any kind merit their inclusion. Additionally, on a perfect system such as this adjustments of any kind, including resonance control, are unnecessary since perfection obviously cannot be improved upon. I have sadly resigned myself to the reality that an audio peon such as myself has to attempt to maximize the performance of the lowly components in my audio system by nudging their aggregate sound in the direction of what more than fifty years around the sound of live acoustic instruments (for probably an average of four hours each and every day) tells my ears what neutrality (musicality) truly is.  Affirmation and the silver lining for me is that in the case of my chosen tone arm the designer of this piece of audio genius agrees with what those ears are telling me. 
Saludos.