Eminent Technology ET-2 Tonearm Owners

Re I beam compliance

I think what Bruce is saying is he is using the decoupling of the balance weights to reduce the effective horizontal mass which allows the use of heavier arm components with their inherent increased stiffness. This seems to imply the use of the single leaf beam to provide the max decoupling, but the best answer is complicated by the compliance of the cartridge you are using.

If I understand correctly the selection of heavier weights close in or smaller weights further out also depends on cartridge compliance and can be verified by measuring the horizontal resonance frequency with a test record.

Changing the compliance of the beam will have a significant effect on the resonance with the stiffer beam increasing the resonant frequency. I may have that backwards but the idea that it changes with the I beam coupling is correct.

The stiffness of the component parts of the arm are physical factors that cannot be changed by anything attached such as I beam and balance weights. The amount of deflection in the arm components however will change with the change in weight and coupling of the I beam assembly. This deflection is however vanishingly small except perhaps at the I beam spring.

For what it's worth, I have used this arm for about twenty two years, and have used more cartridges (of all persuasions) than I can remember. While the effect of lower compliance at the I-beam spring has been most noticeable with low compliance/high rigidity MC's, the effect has been consistent with all types of cartridges, including high compliance MM's. I think it's important to remember that issues involving resonance and resonant frequency can be rather mysterious, and since their effects are audible mainly (but not only) as effects on tonal balance, that system synergy/personal preference re tonal balance are an important part of the equation.

The ears always rule. Didn't mean to suggest otherwise.

If things always worked as physics suggests then this treck would be much easier.

Well said!

Hi everyone, very interesting topic! I have obtained a used ET2 with Bruce’s upgrade 2.5 bearing, but have yet to set it up.

I am very interested in the discussion on the I-beam compliance. As far as I can tell, the arm on the Walker Proscenium turntable (which is of similar design to the ET2) has a direct couple counterweight. Since the Walker is being regarded as one of the best, I was thinking of modifying the ET2 in such manner.

I wonder what are the pros and cons to the 2 different approaches.