Different length tonearm why ?

[Barry]

Pivoted tonearms and linear tracking tonearms each have their own set of compromises - neither are perfect.

[Ammonite Audio]

Exactly!

[Qwin]

Again, what specific compromise, give me one thing to work with.

I can and have, named some compromises, that have to be made on a pivoting arms.

None of these apply to the linear tracker I linked to, so what is the trade off with that design?

You can't argue with generalisations.

[killie99]

Here's summary of problems with linear trackers http://forums.stevehoffman.tv/thread...orth-it.75901/

[Qwin]

Here's summary of problems with linear trackers http://forums.stevehoffman.tv/thread...orth-it.75901/

Comments made in 2006, not much relating to the design I linked to?

It names the same things I did, as design issues for a pivoting arm.

Other than saying an air bearing is superior to a ball race. The only criticism seems to be "what if the air pump packs in"

The vertical/horizontal mass is not an issue on my linked design as it is the reverse situation to what is suggested and the comments were probably referring to a specific type of design, so would be relevant in that case, and several older designs.

There are always going to be differences in individual designs, for both types and I'm not promoting one generic type as better sounding than the other, there will be good and bad for both.

But there is less compromise in a linear design, it is a more elegant engineering solution and I would say the article almost favours linear.

[Barry]

I wouldn't dispute the fact that your Terminator is a good tonearm, but it is not without compromises:

Dissimilar effective mass in the horizontal and vertical plane, leading to dissimilar cartridge-arm resonant frequencies,

Short arm wand length exacerbates warp-wow, and scrub-flutter effects,

Long length of unshielded cartridge wiring used,

Noise of the pump and of the air issuing from the bearing.

[Qwin]

I wouldn't dispute the fact that your Terminator is a good tonearm, but it is not without compromises:

1.Dissimilar effective mass in the horizontal and vertical plane, leading to dissimilar cartridge-arm resonant frequencies,

2.Short arm wand length exacerbates warp-wow, and scrub-flutter effects,

3.Long length of unshielded cartridge wiring used,

4.Noise of the pump and of the air issuing from the bearing.

Like you say all designs have issues and compromises.

On your points, I would comment as follows.

1. I don't know how this can be translated into audible effects, is dissimilar effective mass a major problem. The arm is less prone to cartridge matching issues due to compliance than most, it seems to work with a very wide range.
2. So if the record is poor (warp) it is likely to sound bad. Never heard the term scrub-flutter. In practice, many say with this design the shorter the better and they back the cartridge right up the slots. Can't vouch for that myself.
3. Has no audible effect in my set up with 700mm length cable. If it was a problem I could always use the balanced cable option, or short cable to Phono/Coax, much the same as conversional tone arm cable, then coax. So applies to both arm types really.
4. No noise from the pump as its in the next room. I can't hear any air from the bearing at 300mm with the system muted.

I think the post has been off topic for long enough, sorry to the OP for the deviation.

[paulf-2007]

The transfi linear tracker is somewhat ugly and lack of dimensions put me off as I couldn't tell if it would fit my turntable.
As a rough comparison I heard a 301 with air bearing arm and ortofon A90 cart against a collaro 2010 with Diy 12" oak unipivot with Benz micro gold belonging to me at the time and the owner of the 301 said he couldn't really say which was better but if pushed said maybe the Ortofon A90 just had the edge, at £3500 I would hope it would. The air bearing arm was set up optimally before you get started on that. I've always fancied a clearaudio linear arm but couldn't run to that kind of silly money.

[Barry]

1. I don't know how this can be translated into audible effects, is dissimilar effective mass a major problem. The arm is less prone to cartridge matching issues due to compliance than most, it seems to work with a very wide range.

It is the grossly dissimilar effective masses in the vertical and horizontal planes that most troubles me.

Let us take the case of a typical cartridge: the Denon 103. This has a mass of 8.5g. The quoted compliance (at 100Hz) is 5 10^-6 cm/dyne, so at ~ 10Hz it is 7.5 – 10. 10^-6 cm/dyne. With a quoted arm effective mass of 80g in the horizontal plane, the (calculated) cartridge/arm resonance will lay between 5.3 – 6.2Hz, which is low enough to show up problems with foot falls unless the deck is very well isolated from the floor. In the vertical plane, with a quoted arm effective mass of 3g, the cartridge/arm resonance will lay between 14.8 – 17.1Hz, which might cause any resonance to intrude into and effect the low frequency response of the system.

The situation is worse with Decca cartridges, which themselves have dissimilar compliance figures in the horzontal and vertical planes. Typical figures quoted by Decca are 12.10^-6 dyne/cm in the horizontal plane and 5.10^-6 cm/dyne in the vertical plane. The mass of a Decca Mk.V or Mk. VI is 5.8g, so in the horizontal plane the cartridge arm resonance will lay in the region 4.9 – 6.3Hz. Likewise the cartridge/ arm resonance in the vertical plane will lay in the region 24 – 28Hz. The latter, unless very well damped, will definitely affect the low frequency response of, and possibly overload the phonostage.

2. So if the record is poor (warp) it is likely to sound bad.
Never heard the term scrub-flutter. In practice, many say with this design the shorter the better and they back the cartridge right up the slots. Can't vouch for that myself.

Scrub flutter is a term, which describes the effect of longitudinal modulation of the stylus as it rides over a warp. If the warp is severe, the cartridge will bounce up and down after the warp (in much the same way as a car can bounce up and down after riding a speed bump, if the suspension is not sufficiently well damped). The result of this damped vertical motion is to cause the cantilever to pivot about the tip and the stylus tip will move back and forth longitudinally in the groove, hence the term ‘scrub flutter’. The size of this effect depends on the severity of the warp, the mass of the cartridge and on the compliance of the cantilever suspension. It is exacerbated in arms of short length.

3. Has no audible effect in my set up with 700mm length cable. If it was a problem I could always use the balanced cable option, or short cable to Phono/Coax, much the same as conversional tone arm cable, then coax. So applies to both arm types really.

I was referring to the fine wires emerging from the cartridge carrier, not to the cables between the arm base and the phonostage. Obviously those fine wires must be sufficiently close together to be able to reject common-mode interference such as RFI and/or mains hum. Do the wires have to be ‘dressed’ so as to minimise their effect on the motion of the slide?

4. No noise from the pump as its in the next room. I can't hear any air from the bearing at 300mm with the system muted.

Fair enough – though having to place the pump in another room is a bit of an imposition. Isn’t there a pressure drop over the length of air pipe?



Clearly you experience none of these problems, and are happy with your arm, but in my opinion they are compromises.

There are a couple of features which I do like about the Terminator arm: the ability to adjust VTA/SRA easily (and whilst the record is playing?), and the ability to change arm carriers should one wish to swap cartridges quickly and easily.

[Qwin]

Paul - Looks are a personal thing, for what its worth, I like it.

"and lack of dimensions put me off as I couldn't tell if it would fit my turntable"
I don't know how long ago your talking about, but there has been a dimensioned square on the Trans-fi Audio site for several years that I know of.
If you have a fixing hole on your TT, anywhere within the square, it will fit.