Reed 5T Opinions

I saw the 5T at a show.  The base looks like it is too large for my Basis Debut.  What a relief, I won’t be tempted.  It is a thing of beauty, and the engineering appears to account for and mitigate all of the shortcomings of linear tracking design (except cost).  It works on the same principle as the Shroeder LT arm, except the rotating base is powered by a motor controlled by a laser sensor whereas the LT base moves from the drag of the stylus playing the groove and is controlled by magnets.  I wonder how these two arms compare in performance.

"Normally this friction just generates heat." ...and the skating force in a conventional pivoted tonearm.

The term "zenith" seems to have been re-invented for our particular obsession.  If you look it up, there is no dictionary definition that fits Mijostyn's definition, but I think he got it right as it now applies to vinyl reproduction.  A friend who is well known in the industry has been looking closely at zenith for typical cartridges and typical alignments.  As I understand his messages to me, he finds that almost never is it perfectly right.  We are all living with bad zenith.  BAD, I tell you!

Sounds like the Reed 5A is somewhat like the Swiss Thales.  It just stands to reason that the complex bearing structure, no matter how beautifully wrought, must generate friction.  It remains to be seen how or whether that affects SQ.  Based on Molly's testimony probably not much if at all.

The 5a is based on a design like the Thales arm and so it has additional pivots to locate the arm.  That is not the case with the 5T.  With the 5T the arm’s motion is only restricted by conventional pivots.  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.  Other designs have used optical sensors and servos (like the B&O Beogram 4000), but, the slow rotation of the arm base is supposedly smoother and less likely to cause vibration.

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.

@larryi, Of course they would say that. I have a relatively cheap USB microscope and I can see the long axis on modern extreme styluses such as the Gyger S. I do not have a measurement grid so I have to ball park it and since you can not see the cantilever you have to make sure it is perfectly aligned in the field which with a decent stage is not that hard. If the styluses i currently own have an error I am confident it is less than 1 degree. If I bought a cartridge that had a significant zenith error I would not be sending it to Wally Tools. It would be going back to the manufacturer as defective.

@lewm , quite correct in an offset arm but in these arms the wand is straight so little to no skating force is generated. More bearings are always a liability as you suggest which is why I prefer the Schroder LT. It has normal vertical and horizontal bearings and a magnets control the position of the single secondary horizontal bearing.  I would have gotten the Schroder LT but it requires a turntable that takes a 12" arm. The only table I am interested in that will do that is the Dohmann Helix but I refuse to waste money having to buy the vacuum up-grade when it is released if ever. If not then I am not interested. I am toying with the idea of modifying the Sota's plinth for the LT but in order to get an idea of what it would take I would have to have an LT in hand meaning I would have to buy one. That is a pretty big leap for something you might not be able to do.

@dover that is not the way it works dover. The motor is running continuously and the laser is pinpoint. It simply adjusts the motor's speed. If you look at the arm wand it's vertical and horizontal effective mass is virtually identical. In the case of your arm it is wildly different. What this amounts to is a very low horizontal resonance point. Your arm bounces across the record at 2-3 Hz. You can stop this with damping but then you generate reverse skating. In short, It is a terrible design.