Eminent Technology ET-2 Tonearm Owners

I remember very clearly that one of the things that reviewers seemed to agree on when comparing the newly released ET2 to the ET1 was the more powerful and more extended bass performance of the ET1. This was described as the one area where the original bested the 2. I would be particularly interested in how the arm wand attached to the bearing tube in the ET1; amount of decoupling and any other physical differences between the two arms that might contribute to this difference. Thanks.

Frogman.

Look to the other end of the arm and compare the counterweight attachment. If you are using a low compliance cart on an ET2, this is the main cause of diminished bass extension. Calculate your FR using the ET2 manual formula. Around 7Hz or above and you are missing the lowest registers. The math on this is very clear.
Further the quite flexible goose neck and arm pillar on the ET2 don't help.

Frogman,
I had the luxury of having both the ET1 and ET2 in my showroom in the 80's mounted on a variety of turntables along with other top arms of the day such as SME V, Zeta, Alphason, Dynavector, Odyssey, Sumiko The Arm, Goldmund, Syrinx PU2/3, etc
The ET1 had a bloated bass, slower and less tuneful than the ET2.
The ET2 was clearly more transparent than the ET1 by a considerable margin.

The improvements to the ET2 are as follows :

Decoupled Counterweight - This offers 3 advantages.
The decoupled counterweight reduces the horizontal mass
The decoupled counterweight splits the low frequency fundamental resonance, which results in two peaks of lower amplitude, improving the LF performance as demonstrated in Thigpens testing.
The decoupled counterweight provides the capability to tune the decoupling spring to the cartridge.

The maths may be taxing for some, but the Thigpens ET site has documented test results demonstrating the advantage of the decoupled counterweight design. It is incomprehensible as to why any individual would ignore Thigpens test results and convert the ET2 back to the ET1 format in respect of the counterweight, unless their system does not have the resolution to take advantage of this patented decoupled counterweight design, which yields a quicker and more tuneful bass as you have found in your testing.

Adjustable VTA that maintains correct position of the stylus

The tower provides easy adjustment to ensure the level of the horizontal bearing is congruent to the platter surface.

Here is a pic
http://www.eminent-tech.com/history/modelone.jpg

Dover.

Up till recently you have been telling us all repeatedly that the counterweight decoupling spring is active at eccentric record frequencies and that at these frequencies my arm is up to 300% heavier than a standard ET2. We now all know that you are wrong and that the spring is in fact rigid at this low frequency making the effective mass seen by the cart in standard ET2's in the same ball park as my arm with a fixed counterweight.
The math which proves this effect, below FR, shows that above FR the decoupling spring is active and it dramatically reduces the arms effective mass. This is a brilliant solution if you are using a high compliance cartridge. But this same math shows that if the FR is around 7Hz or above, we get bass attenuation. Low compliance carts will exhibit a FR in this danger zone of 7Hz and above. If we fix the counterweight, to push FR below the danger zone, we unfortunately get a big, high Q peak at FR. Exactly what the leaf spring fixes for us. So there is a conundrum here. Live without the last bit of bass extension or fix the counterweight and experience bloated bass performance, not due to excessive bass but due to the FM phase problems propagating up from FR into the audible spectrum. On the bloated bass topic we agree.

But there are solutions to this. Run the arm at pressures below design and dress the lead out wires to resist lateral movement. Not a very elegant solution but it kinda works. Or far more effective, ran at design pressures and use an oil trough. See BT's test data on this where he uses his arm "set up so that a high amplitude Q existed" (a fixed counterweight exhibits a high Q) and then adds the oil trough. The resultant response graph he publishes in the oil trough manual, shows a critically damped system with zero resonant peak and importantly he mentions "the ET2 with a damping trough will exhibit almost perfect low frequency phase response"
No more bloated bass and with full LF extension. Lovely.

Thanks for the comments. I had forgotten that the ET1's counterweight arrangement was not decoupled. While I can't speak to why the reviewers that I mentioned considered the weightier bass of the 1 to be "superior", I do agree with Dover that, based on my experimentation, decoupling the counter weight wand does result in bass that is more tuneful and correctly speedy than with more direct coupling.