Reed 5T Opinions

When the arm is slightly out of tangent, a laser beam and sensor detects this condition and a servo motor slowly rotates base that the arm is on to reestablish proper geometry.  

So in a nutshell it is just like digital - only a little bit out all of the time ( apart from the start ).

Reminds me of the Goldmund linear tracker waltzing across the record -

2 steps forward, 1 step back, hippity hoppity boo, I see a new cartridge for you.

At least with the Goldmund you had a flashing led to show you how often the arm was out ( most ).

I'll stick to my air bearing linear tracking Eminent Technology ET2 if I want zero tracking angle error.

@mijostyn 

Your arm bounces across the record at 2-3 Hz. 

I assume you are talking about the Eminent Technology ET2.

How do you come to this conclusion.

@thekong 

An interesting white paper.

The ET2 horizontal effective mass can be as low as 25g less the decoupled counterweight compared to the 80g Kuzma Airline.

Kuzma ignores tracking and focus's only on resonance. I always thought the target of 8-10hz was partially based on keeping it above footfall on sprung floors which is typically around 4hz.

If you examine the Shure white papers on tracking, they have found that the fundamental resonance, if not dealt with properly, causes a scrubbing motion from the cantilever/stylus assembly. This causes tracking issues and of course distortion in the bottom and its harmonics that will distort up into the audible regions. I assume this is why they came up with the stabiliser brush.

Kuzma makes no comment on the impact of high mass on tracking at low frequencies, and there is no measurement indicated in the white paper.

Even Bruce Thigpen of ET states that on eccentric records, arms with high horizontal mass will be less accurate than lower mass arms.

Bruce Thigpen has measured wow and flutter on pivoted arms versus air bearing linear tracking and can demonstrate the linear tracker has lower wow and flutter.

His argument, supported by measurement is that there is typically more wow and flutter from a pivoted arm than from the TT itself.

@larryi 

The dramatic difference in the inertial mass of air-bearing arms in the horizontal and vertical planes may be a problem or it may be a benefit. 

It's a benefit according to Bruce Thigpen.

By having differential effective mass in the horizontal and vertical plains you have 2 much lower amplitude resonant frequencies instead of 1 large one. If you have both resonant frequencies at the same point the amplitude is compounded along with the deleterious effects on tracking.

Bruce also makes the point that the ET2 does not pivot at low frequencies, whereas servo arms and low surface area air bearing arms will pivot at low frequencies - they are not rigid at low frequencies.

@mijostyn 

Also, what on god's green earth makes you think the counter balance of the ET arm is decoupled? It has mass does it not? 

From your comments it would appear that you have never seen an ET2 or understand it.

The counterweight sits on the end of an I beam, which is connected to the air bearing spindle via a leaf spring. 

Try leaving your car door open and driving off - does the door stay open - no its hinged - and so as the car moves the door rotates about the hinge.

ET2 works exactly the same. 

Why don't you go to the Eminent Technology site and actually read up on the arm - you might learn more clearly how it actually works instead of guessing..

@mijostyn 

He definitely has moments of genius but he will make whatever people think they want to buy so, he makes one of everything and is committed to not much. 

Franc Kuzma has been producing audio products for many years. His turntables and tonearms are lauded around the world - even by yourself on these forums.

How many turntables and arms have you manufactured and sold ?