New Schroeder linear tonearm, any thoughts?

Hi Lewm,
That base in the Xact audio picture is just that: a base/armboard that's part of a/some turntable(a Kodo "The Beat" in this case), not part the arm. It can be mounted on any deck that allows for a spindle to center of main shaft distance of 276mm.

Best,

Frank

Hi,
The eff. mass was stated as ranging from 14-21gr. since one can exchange the Certal cartridge mounting plates for lighter or heavier types(phenolic, brass,etc...), just as on my "old" arms.
The eff. mass is only about 20% higher in the lateral plane vs. the vertical plane.
Why? Most of the additional mass(pivoting bar) is near the pivot AND the linkage isn't rigid, but the fluxlines will "bend" if accelerated swiftly(like when the lateral resonance is exited, which, for other reasons is nearly impossible in this design). At the same time, the magnet/guide bar acts a an eddy current brake.
"Conventional" linear tracking arms(not the Simplicity and some other pivoted tangentially tracking arms) typically have a 8-20 times(800-2000%) higher eff. mass in the lateral plane.....

Hope this helps :-)
Have a great weekend,

Frank

Hi,

" Apparently this helps nudge."...

Nope... it's just there to "equalize" all forces acting on the stylus. If it was some form of skating-compensation or -generation arrangement(to "nudge" it inwards), an increase of VTF would change the tendency to move either inwards or outwards. But it doesn't...
Kind of the same as if you were to raise VTF on an air bearing arm that isn't level. It wouldn't move/accelerate any faster if you were to increase VTF. Solely a question of gravity acting on the entire assembly.

Cheers,

Frank

Hi,
Nope... - "nudging" the arm towards the center of the record isn't required(that implies poor quality bearings are used...). The triangular base can be adjusted so that there is no tendency to move either inwards nor outwards. One can even compensate for the (very minute) influence of the wiring.
Two of the three screws that make contact with the turntable base(apart from the M6 locking screw) can be adjusted, so that the arm base allows for a little more than +/-1° change in horizontal orientation to i.e. compensate for an armboard that's not parallel with the platter.

Best,

Frank

Sorry for the (kind of) double posting. The first one didn't appear for a long time and I thought I had accidentally erased it...

Best,

Frank

Hi Lewn,
"What do you think?"

I prefer to refrain from criticizing particular design decisions of other tonearm designers or manufacturers, but I will try to comment( which will, inevitably, contain judgement, I know...).

In tangential tracking airbearing arms the disparity between eff. mass lateral vs. vertical is unavoidable, but could be reduced (Rockport, Versa Dynamics...). In order to achive that, the neccesary reduction in eff. length will cause warp wow and pronounced changes in VTA when switching from 120 to 200gr. pressings(to a lesser degree VTF too). Keep the arm longer and you'll have to add a provision for damping: eddy current brake(Dennison, Eminent) or add an anti-resonator(Eminent), all solving one problem for the introduction of one or several others.
If the arm cartridge resonance frequency is "split", a key argument by Dynavector, you will now have to avoid exitation of either(more difficult to achieve than you'd think), therefore Dynavector arms feature a massive eddy current brake. The "split plane " design is by no means an invention of Dynavector. Some famous arms(i.e. Gray 106, Shure M16 Dynetic...) preceeded them by decades. Those were used on non-suspended decks(broadcast console-mounted), so the risk of lateral exitation was reduced mainly to what record eccentricity could trigger. And they did it mainly to allow for the use of cartridges that "tracked lighter".
Bearing design for such an arm offers options not available to those sticking to "conventional" arrangements(like gimballed arms), so there are potential and in some cases realized advantages.

Once you use an arm with a high eff. lateral mass on a suspended deck or, to be found often, on top of a tall rack with tons of gear that is supposed to be rigid(hahaha....think Eiffel Tower with King Kong on the Observation platform swinging happily, huiii!), you'll invite all sorts of problems that may not manifest themselves directly, but through effects such as transformer saturation, increased power requirement or intermodulation distorsion.
Besides that, the shift of mass will shift the center of gravity of the deck, forcing it out of a level position. Not exactly desirable for zero friction arms...
An Oracle Delphi with ET2 tonearm was a rather popular combination at some time. While it could yield impressive sonic results, I never understood why it was promoted to that degree other than for marketing purposes.
The Dynavector's excellent bass rendition predominatly stems from the (eddy current)damping in the lateral plane. It's mass distribution is another reason.
Bass below 100Hz is cut in mono, purely lateral...

Best,

Frank

Hello Royaloak,
Skating force varies between 4 and 18% of the VTF, depending upon all sorts of factors. Any compensation will result in a compromise. My suggestion is such a compromise, reducing the sidethrust/lateral preload on the cantilever and, at the same time, retaining an amount of skating compensation that will be sufficient to keep uneven stylus/groove wear at a VERY low level.
The often described method of using the tracking ability("torture") track on a test record will lead to overcompensation due to the fact that there is no 70µ, 80µ or higher constant modulation to be found on any record. Peaks: yes! Permanent signal: not supposed to exceed 50µ, typically around 20µ.
Since modulation causes drag, it will also "modulate" skating, so why compensate for a maximum that rarely, if ever, occurs.
Overcompensation will often cause cartridge dampers to assume an asymmetrical position after a while(cantilever no longer parallel with the cartridge body/generator axis). Once you notice that, you ought to send it back to the manufacturer to have it re-aligned. The stylus(when kept clean) usually outlasts the damper/its proper orientation.

Try a dynamic Mono(i.e. Sonny Rollins - Saxophone Colossus) record and play the right channel only, then the left channel only. With the antiskating set as high as you mentioned (moving slowly towards the outer edge of the record), you are likely to notice one channel to sound more dynamic than the other. Reduce skating and listen again...

All the best,

Frank

Hello Royaloak,
The reason for the suggested undercompensation is the usually higher than acceptable sidethrust on the cantilever, caused by an antiskating mechanism. While the force excerted by the stylus/diamond on both groove walls may be equalized, it causes a permanent cantilever displacement( since the antiskating acts on the arm, not the diamond itself), resulting in a non linear behaviour.
Imagine a speaker being exposed to a certain amount of a DC voltage. The null position of the speaker(where it rests when no signal is present) will have moved forward or backward, depending upon the polarity of said DC voltage. The maximum cone displacement is reached sooner in one direction, it takes a different amount of force to move it forward vs. moving it backward.
Same for a cantilever that has a conventional suspension, dynamic gradation is foreshortened and the resolution of microdetail(what happens around the Null point) diminished.
If one is to reduce the skating compensation to zero, the non linearities caused by non-equal pressure of the diamond on the groove walls will have a larger influence, so zero antiskating isn't the answer either(imho).
And I have not even touched the issue of the coil position against the magnetic circuit when a preload is present. Not as severe an issue and highly generator design dependent, but...

As said in the manual of my arms, my suggestion is a starting point, not an absolute(ly perfect) setting. If your method yields better results, - or results you like better, then, by all means, go by that!

All the best,

Frank