Eminent Technology ET-2 Tonearm Owners

Ct0517 - further to my previous post, my experiments with copper mats is that you get more out of them when used in conjunction with a record clamp to ensure tight coupling of the record to the copper.

06-23-13: Richardkrebs
My TT and Pre happen to sit on granite surface plates, surplus left overs from our machin shop. They are used, not of their flatness but their energy sinking properties.

This is not correct. Granite is very very hard and therefore tends to pass energy straight through in both directions, it does not sink energy in of itself. Therefore what the granite sits on becomes important. For example HRS use a polymer to dampen the natural resonance their granite shelves.
Readers should also be aware that granite contains high levels of uranium and can be considered radioactive.
My own experience with granite is a hard edge to the sound in the upper mid lower treble - granite has a definite sonic signature related to it's natural resonance.

Slaw - I assume you've seen the 3D printed VPI arms... any thoughts?

Slaw I have owned the JMW 12 in the past. Here is a pic of my past JMW 12 with a pic from the web of the new VPI 3d tonearm.

http://cgim.audiogon.com/i/vs/i/f/1372035211.jpg

Other than materials they still look really similar to me? The wire placement doesn’t seem to have changed. It was used for antiskate as it would push back. The newer VPI arms have additional antiskate on the new arm. Not sure how this tonearm can be one piece?

what does the point in the cup rest on? I would think some stainless is needed on the inside of the female part.

Dover
Correction, you have not heard the full krebs upgrade.Two people in NZ have.
Please confine your comments in posts to those that are actually true.

06-24-13: Richardkrebs
Dover
Correction, you have not heard the full krebs upgrade.Two people in NZ have.
Please confine your comments in posts to those that are actually true.

Richardkrebs
Your assertion is wrong.
I have listened at length to the Technics krebsupgrade on 2 occasions in the past few months. I stand by my comments. At least 3 of your turntables are in NZ and some overseas. I know some of the owners well.

In order to maintain standards and ensure authenticity, I have initiated the use of identification labels on my upgrade. Going forward, only TTs that meet these standards will be shipped with this authentication. Every TT done by Bill meets these standards. In contrast the 2 off MK2s done in NZ do not, being prototype mules 1 and 2, they were effectively a work in progress. Both of these owners are aware of this and are getting their units brought up to spec FOC. This developmental work has meant that any brand DD TT can now be upgraded with a high level of confidence, circumventing the prototype stage.
Baring imports, there is only one TT in NZ that meets my requirements, a MK3, and that is mine.

Back on subject, Chris, we are waiting to hear about the mag wand performance.

06-25-13: Richardkrebs
In order to maintain standards and ensure authenticity…
In contrast the 2 off MK2s done in NZ do not, being prototype mules 1 and 2, they were effectively a work in progress. Both of these owners are aware of this and are getting their units brought up to spec FOC. This developmental work has meant that any brand DD TT can now be upgraded with a high level of confidence, circumventing the prototype stage.
Baring imports, there is only one TT in NZ that meets my requirements, a MK3, and that is mine.

Richardkrebs
The fact that they are advertised as having your US$800 upgrade says otherwise. I quote from the published advertisements here in New zealand -

The Technics SP 10 MK II has had the Richard Krebs US $800 upgrade.

I was advised that they had your upgrade and at no time was the word mule or prototype mentioned.
Your explanation conflicts with both the advertising and the descriptions given to me by the retailers.
Your post of 06-24-13 accused me of making untrue statements. You owe me an apology.

The Mag Wand after a couple listens.

Just thinking about it - we have talked at length here about the vertical and horizontal masses. My personal experience has been any time I can increase the vertical mass of the ET2 arm itself - it is a good thing to my ears. With that increasing the armwand weight itself also increases the ET2’s horizontal mass. So its a kind of game. You need to trust your ears.

Turning the counterweight cap down is significant in my system. I keep the weights at around 3:30 on the clock. If you don’t believe it try turning the weights up to 2:00 and see what happens to the sound using the middle of the air bearing spindle at 3:00 as a reference.

I left the MM that was on there as to change only one variable at a time. What I got was more impact, presence, aggressiveness, attack,.... weightier sounds overall.

One example Dire Straits – self titled album. Guitar plucks on Water of Love. The Bass impact on Six Blade Knife. The weightiness to the voice. This is immediately apparent and then you settle into the sound. So would more weight and attack be a good or bad thing in your own system ? Only each of us can answer that. When my teenage daughter plays our 1958 Heintzman piano - her mood - affects her play. Sometimes the piano has more attack and weight sometimes less. I have learned she is more approachable when the sound has less attack in it and the sound is more delicate and graceful.

I asked Bruce how he makes the mag wand.

Chris,

It is turned from one piece of magnesium solid bar stock. We turn the O.D., bore the I.D. and then heat the tube to 450F to form the headshell end of the tube in a die. Thank you very much.

brucet

Can someone explain to me what “turn the OD, bore the I.D.” means ?

It required one extra skinny lead weight for balancing over the Carbon Fibre armwand with lead (only) weights setup according to Dorothy.

OD is 'outside diameter'.
ID is 'inside diameter'.

Chris
Good to read about the mag wands performance. Thanks for giving us a clear view on what it does. Also impressive engineering all over again from Bruce.

Thanks Henry – its the words turn and bore that are intriguing to me.
Richard - I would like to see a video of this whole process.
I have seen many videos of how records are made and have been to one record plant many years ago.
The old record making videos always show a bunch of ladies at the end of the process just prior to inserting them into sleeves; They could all pass for your Aunt (fill in the name). They represent quality control as they eyeball the records. :^)

Chris.
When Bruce machines the wand, I assume that this is what happens...
The bore thing is basically drilling a hole to create the ID dimension. Sometimes the drill is rotated, some times the work piece (bar) is rotated. It depends upon the machining centre. For complex internal shapes it is possible to undercut the workpiece such that a larger ID is created say in the center section compared to the two ends of the resultant hole.
The turn process is like moving a chisel along the outside axis of the spinning bar to create the OD dimensions. The chisel can be moved in and out to create different ODs along the length of the bar.

I could send you a video of our milling machines running but you don't see a lot as the work piece is flooded in cutting fluid to keep it and the tools cool, lubricated and help with swarf removal.

The art in this process is getting the feed ( how fast you pass the cutting tool along the surface ) and speed rates ( how fast you spin the work piece or cutting tool ) optimized to produce the required tolerances and surface finish, in sync with the conflicting requirement of finished product thru put, tool wear, and machine loading.

Thanks for the info Richard.

I have watched my Brass Armpod being cut from this

Blurry picture – it was moving I had to make sure I wasn’t hit as it swung over to the cutting table.

I also watched my SS Legs that are bolted into my previous version SP10 setup being made. The current version has threads at both ends.

This magnesium armtube is a very different beast. :^)

Cheers

Dover.
Please contact me via my website. There, I can answer your questions and any others you may have in detail.
Thank you for your interest in the upgrade.

I hope everyone is enjoying summer.
At least those on this side of the equator.
I am enjoying my summer

I have an extra aluminum arm wand if anyone needs one.

It can be used as is or you can have Bruce convert it to Carbon Fibre.

If anyone is interested contact me by pm. Its available with
stock wiring or without.

Cheers

Richardkrebs: I have aquired the necessary equipment and will be constructing my TT in my own shop. Your comment regarding constructing the arm pillar and pod ( assumming we are talking about the same thing) as one, doesn't seem necessary to me and in fact seems a step backward, IMO. I choose to go with Bruce's original design as much as possible, bowing to his expertise on design and knowledge. I will be using the 'granite surface plate' to have an accurate 'plane' as a reference for the build and final placement in my system, not for actual use in my system. The arm's final trueness will have at least one separate adjustment, the 3 point ET arrangement. My focus is to make each of the four portions 'true' in every step of the build process, all the while knowing I have multiple other options available in my personal system/set-up that I can count on to get me to the 'true' point. My personal goal is perfection, then knowing that isn't always acheivable, I can rely on the ET adjustment/ arrangement.
I have to say that as regards to using acrylic as a platform for the vinyl record and in my own system, IE: the armboard, I do agree with Fremer that this isn't the best material for great transient response, tight, controlled musical bass @ realistic sound that I crave. Of coarse this is solely from my own system experience and personal preference.

...... another important factor. I, as I'm sure you all are aware, from decades of listening, the effects of certain materials on sound quality. This is where most of us have experience that novices don't or will have to wait for, until these important factors can properly be evaluated in your projects. This is where time listening, experience, and most of all, patience is critical in going forward with aftermarket projects.

An lp recommendation... Jason Isbell "Southeastern". STRONG!

Slaw.
It will be intersting to read about your TT project.
Re the arm pod and pillar, perhaps I have missunderstood?
If the arm pod has three adjustable feet it would be possible to replicate the effect of the three feet currently used by Bruce in the arm pillar. It would be easy enough to replicate the curved VTA arrangement of the pillar in a one piece pillar / pod. The three adjustable feet would need to employ finer threads on the screws to avoid them being too coarse in adjustment due to the longer fulcrum. Is this an option?

Agree with you on the acrylic thing. It can have the negative effects you describe. I think that a lot of this has to do with how it is used though. That said if/when I build another TT, I will almost certainly use a different plinth material. Probably durallium or austenetic cast iron.

I use discarded surface plates under the TT and Pre for their vibrational energy transmitting characteristic. They then sit on soft wood and sand which should dissipate this energy. Like you, the original TT and Arm made extensive use of other surface plates, during the build process, to ensure their trueness.

It is great to read about people taking the big step of commiting time and effort to a major project like yours.

Slaw
"I do agree with Fremer that this (acrylic) isn't the best material for great transient response, tight, controlled musical bass @ realistic sound that I crave."

Interestingly, last night, I stumbled on the following comment re the VPI Scout 1.1 platter (Joel Salcido, TAS 40th anniversary issue): This one is Not acrylic and to hear Harry (Weisfeld) tell it, acrylic platters are a thing of the past. It's simply easier to machine metal to tighter tolerances, and the fact they sound better ices the cake.

Back in the Goldmund days, I understood their acrylic platter was for optimum impedance matching (with vinyl). Life moves on huh.

Slaw
"I have to say that as regards to using acrylic as a platform for the vinyl record ......"

Further reading, TAS 40th issue.
Wayne Garcia on the new Rega RP8:

"Most notable is a two-piece, 16mm thick flywheel platter made of float glass, a technique wherein molten glass is Floated over molten tin in order to create the flattest possible surface and overall uniformity of thickness. To form the flywheel platter, Rega joins two separate pieces of float glass to the underside .... adding mass to the circumference.

Damn marvellous I say!

Yes, some interesting materials and ideas being used in platters these days. Isn't VPI also making a ceramic one?

Then the Clearaudio, in their Statement and Basis are using plastics.

Take your pick.

John I have owned 3 regas........all digital

Planet, planet2000, my current Saturn of 8 or so years ?, is one of my current digital players.
It sits on 3 symposium rollerblocks

Rega was one of the last companies to enter the digital world.

So I guess I like the company but I have no experience or knowledge of their analog items.

The RP8?

how do you put an ET2 on that ? :^)

I imagine TT designers trash many prototype materials before arriving at what they choose for their product. It should be a requirement imo, especially for some of the higher priced tables to understand the room/gear used to arrived at a turntable design.
This should be published information.

Regarding building turntables and materials used.

Here is a list of materials along with a number beside them. The number indicates the materials ability to pass thru sound (a high number) or hinder sound (a lower number).

The higher the number allows a better pass thru of sound. the lower number deadens, inhibits, absorbs.

Material Z0 [MRayls]

aluminium.........17
brass.............37
copper............42
cast iron.........37
lead..............25
magnesium.........10
steel.............45
tin...............24
tungsten..........101
araldite..........4-13
brick.............15
concrete..........7-10
glass.............10-15
granite...........27
marble............10
slate.............12
all plastics......1-4
all wood..........1-4
except cork.......0.1
carbon fibre......30

This data is informational only and was taken from this site.

http://qualia.webs.com/plinthbuilding.htm

"Another property of materials is the acoustic impedance, that is, how easily sound passes from one material to another. Nearly all the data available is concerned with supersonic frequencies of sound, typically 5 MHz, so not really useful in the audio range. However, it does suggest that getting sound from one material to another seems to be dependent on their respective acoustic impedances, easily calculated as:

Z0 = p x c where Z0 is the acoustic impedance, p is rho, for density, c is the speed of sound through the material [longitudinal wave velocity]
Some acoustic impedances of common materials: Z0 in N•s/m³ /106"

So to transfer sound from one material to another effectively may mean using materials with similar acoustic impedances, or, to hinder transfer, (as in isolation), choosing materials with very different acoustic impedances.

What about rounded edges for the plinth/armpod materials themselves over straight edge; to better deal with resonances? This is done with speakers.

Chris.

My trash bin....
Too many years ago to count, I went about building 5 off BD TTs in quick succession. The platter was aluminium, bearing had a tungsten carbide thrust plate with replacable steel ball on the shaft. All five were of the same design, the difference being the plinth material. I simply changed the bearing, platter, motor and arm from one to the other.
#1 Laminated MDF. Slooow and colored
#2 Laminated hardboard( like compressed MDF.) Better but still slow and colored.
#3 Concrete. Hard and bright
#4,5 Slate. Quite good, slightly bright, which was mitigated with a lamination of MDF on its base. I sold #5 to a then Linn owner.
After this I went on to build 4 off unipivot arms. Based on the geometry of the Hadcock CH228. They all had saphire bearing cups with ss pins. Brass pillars and magnesium headshells.The only change was the wand material.
#1 epoxy resin infused balsa wood. This was not as stiff as expected and this was reflected in its sound, smeered and soft.
#2 hard wood dowel. Lovely, glorous, romantic but colored.
#3 undamped aluminium tube. Nice and clear with a slight rising top end.
#4 damped thin wall glass tube. Easily the best. Clear and articulate. This was broken awhile later during transportation and I was too devistated to rebuild it.

Does any one else have similar war stories? I am interested in your findings.

Richardkrebs,
With all due respect the sonic signature of the different materials you outline are meaningless unless the rest of the system is described at the time of testing. For example it might well have been that the system was slow and the concrete, whilst sounding hard, may have been showing up coloration elsewhere. I see very little science and no concrete evidence to support your observations.
Furthermore, it is well known that the geometry of the original Hadcock 228 was in fact incorrect and if you had built an arm to that geometry then I'm surprised you could not hear the high tracking error and distortion. Specifically the offset angle was incorrect and this was remedied with the release of the 242 in recent years.

Dover, you wrote regarding Richardkrebs (and Chris/Ct0517 when he changed to his magnesium arm wand, as they used the same methodology) ....

"I see very little science and no concrete evidence to support your observations."

With all due respect, would you please articulate what 'science and concrete evidence' you apply in similar situations.

Richard – interesting findings – thanks for sharing. Sorry to hear about that glass armtube. Would have liked to see a picture of that one.

Chris.
Yes the glass arm was special. I used magnesium from a broken aeroplane wheel hub to mill the headshell. Slotted mounting holes to facilitate correct cartridge alignment.

I have one of the slate TT's somewhere in storage in the attic. Will see if I can find it amongst the detritus of time, maybe post some pics.

Imo – the only thing an amateur (hobbyist / audiophile / music lover) can do is to keep to the golden rule.

Change only one variable at a time.

As an amateur I only need to please myself. I am selfishly in this hobby for me only. I am also my own worst enemy. I know this.

I have known amateur audio friends in the past - who seemed to want to please their friends more.

Now - if I wanted to analyze what I did and tried to put some science at it.

Going back to the post about materials ability to pass sound/resonances.

Higher number being easier to pass – lower meaning it hinders.

I went from a Carbon Fibre wrap aluminum armwand with a Teflon insert.

carbon fibre......30, all plastics......1-4, aluminium.........17

to a heavier Magnesium armwand.

magnesium.........10

everything else stayed the same.

Yes indeed Chris, that is a time honoured method, and can satisfy oneself.

But not Dover - it lacks 'science and concrete evidence.'

Chris: further to your comments on changing to the magnesium wand.

According to Dover, what you heard was meaningless, unless the system was described at the time of testing - it could have been due to colorations elsewhere in the system.

Additionally, without science and concrete evidence, its useless 'just' describing what you heard.

what you heard was meaningless, unless the system was described at the time of testing

John - I list out my gear as well as pictures of the room. I am very interested in seeing what some of the rooms look like downunder. I don’t even need to see the gear. Rooms and speaker (type) placement tell a good story that I find fascinating.

re: science and concrete evidence.

fact - there is no perfect room.

fact - no one has perfect ears.

fact - this means if all our gear was the same our speaker placement would all differ - the room rules.

its the elephant in the room.

cheers

its the elephant in the room

The Room

:^)

I hope no ones counterweight cap looks like the one in this link? This is a easy replacement for a new one - $50 or so.

http://www.ebay.ca/itm/Air-Bearing-Tonearm-Eminent-Technology-Model-two-/330963316997?ssPageName=ADME:B:SS:CA:1123

Not affiliated with this ad.

A good test to see if your ET2, ET 2.5 is set up to play the inside of a record properly.

I mentioned this album earlier.

Dire Straits – self titled 1978
Side Two - finish of the Lions

Not much plastic left at the end of Lions before the label!

Cheers

Been away for a while, hope everyone is well. Chris, the Forsell is still packed in it's boxes. I hope to be able do a shootout between it and my TNT6/ET2 before too long; will keep you posted.

Re your most recent post: just wanted to remind all about the importance of not overtightening the bolt that secures the elbow to the bearing tube (any and all bolts, for that matter). Doing so will certainly misshape the bearing tube and affect tracking the inside of a record.

Hi Frogman

the Forsell is still packed in it's boxes. I hope to be able do a shootout between it and my TNT6/ET2 before too long; will keep you posted.

Exciting shootout ahead. Brings back memories for me. Please let us know how it goes.

Actually Frogman with your knowledge of the ET2; I selfishly would like for you (if you don’t mind :^) - to drill a very small hole (no big deal) in the Forsell and mount your ET2 on it if possible. Compare your ET2 to the Forsell tonearm - on its own home turf. Sort of like vinyls version of “mano a mano” ?
My ET2.5 reached new sonic levels with me once it went onto a table that does not require the thrust bearing. Bearing resonance is real and they (bearings) impart their sound on tables I have owned. Anyone that has tried different bearings and lubricants with their tables know this. Thicker lubricants slow and dull the the music; thinner oil makes it leaner but it loses texture. My JN Lenco bearing is self lubricating. So I was aware of the bearings impact on the sound; but it did not hit home to me until I used a table that had no bearing.
I am willing to bet 100 Canadian Loonies that the Forsell will forse (sic) you to convert the TNT to thread. :^)
Cheers

I may just do that; would be the only fair comparison of the two arms. Interesting comments re thrust bearings; makes complete sense. Re thread drive: I have no doubt its the way to go; just one of the many
unfinished projects and will definitely try it. BTW, spending most of the summer at our upstate place while I play at a couple of summer music festivals and finally had a chance to get the system up here up and running. Vintage Luxman DD has been showing the advantages of DD's pitch stability. But, boy do I miss the tonal qualities of my TNT/ET setup. Also, speed stability yes, but also a strange lack of rhythmic impetus; almost as if the music doesn't move forward the way it should. More tweaking is in order. Regards.

Frogman - I may just do that; would be the only fair comparison of the two arms

That is a review of impressions I would be willing to cough up some coin to read.

something a little different - I came across this.

The man behind this thread. Scroll down to the bottom for a picture of Bruce. His rotary woofer is the only loudspeaker in the world that can reproduce the sound of Niagara Falls accurately.

Falls Fury Rotary woofer

Interesting comments on the Terminator linear tracking arm from Dgarretson on the MM thread who has fabricated a lightweight carriage from carbon finer instead of aluminium....

08-16-13
The wand has dual front and rear counterweights for continuously adjustable vertical effective mass.
Total horizontal mass of arm, cradle, and carbon fiber sled is 45gm, and can be increased by weighting the air sled.
08-18-13:
I've tried it with as little as 35gm horizontal mass and as much as 100gm-- approximating the range of horizontal effective mass from ET to Kuzma airline. So far less horizontal mass sounds better in all instances. This does not hold true for vertical mass.

Just another reminder that the best place for adding lead mass is on the end of a fishing line. It has no place on the ET.

08-19-13: Dover
Interesting comments on the Terminator linear tracking arm from Dgarretson on the MM thread who has fabricated a lightweight carriage from carbon finer instead of aluminium....
08-16-13
The wand has dual front and rear counterweights for continuously adjustable vertical effective mass.
Total horizontal mass of arm, cradle, and carbon fiber sled is 45gm, and can be increased by weighting the air sled.
08-18-13:
I've tried it with as little as 35gm horizontal mass and as much as 100gm-- approximating the range of horizontal effective mass from ET to Kuzma airline. So far less horizontal mass sounds better in all instances. This does not hold true for vertical mass.

Interesting comments from DG as they relate to the Terminator arm. I have only seen pictures of it.

imo - it is not valid comparing the ET2, 2.5 and Kuzma Airline in this manner because although the later Kuzma resembles the ET2 in appearance their design objectives are as different as apples and oranges. This has been discussed here.

Some facts

The Kuzma Airline requires the wires and air tube for damping of the cantilever.
Through private Kuzma owner emails I have learned the Kuzma has difficulty with lower VTF and higher compliant cartridges.
Requires a heavier cartridge with a stiff cantilever. Any Airline owners disagree with this comment? I don't own it and the reason I ask.

The ET2 (2.5) in contrast can play a light high compliant (how about a sonus blue gold at .2gm) or an Acutex 4 series then turn around and play a stiff cantilever on a heavy MC.
The ET2, 2.5 requires neither the tubing or wiring for damping and tracks best with no wiring.

I know this because I use it this way (no wiring) now to level it and have had it track the record this way - once.
I say once because I haven't figured out how to get any sound when I run it this way.

again I ask - how do we make it wireless ?

Johnathan Carr, Peter Ledermann or another cartridge designer if you see this - this thread is at over 150,000 views.

Does anyone have any plans for a wireless cartridge ?
I will buy your beta cartridge even if it means putting in some kind of computer chip in my preamp.

C'mon Nobody likes wires anyway. They just get in the way.

Unless you can set the wires up like Frogman.

http://cgim.audiogon.com/i/vs/i/f/1366422461.jpg

Then we can call it Art.

I have no problem with that.

Remember when phones needed wires. My kids don't - they laugh when I tell them.

The ET2 also has VTA on the fly that doesn't change parameters like VTF.
Set your Airline at the highest and lowest setting and you'll notice your VTF has been altered.
This is an owner confirmed comment.

Does "any" other arm exist that does vta on the fly?
Same thickness records have included cut angles that are random from the different record plants.
How do you guys deal with this?

The ET2 can also be tuned for different compliance cartridges MC and MM.
Cheers

08-21-13: Ct0517
08-19-13: Dover
Interesting comments on the Terminator linear tracking arm from Dgarretson on the MM thread who has fabricated a lightweight carriage from carbon finer instead of aluminium....
08-16-13
The wand has dual front and rear counterweights for continuously adjustable vertical effective mass.
Total horizontal mass of arm, cradle, and carbon fiber sled is 45gm, and can be increased by weighting the air sled.
08-18-13:
I've tried it with as little as 35gm horizontal mass and as much as 100gm-- approximating the range of horizontal effective mass from ET to Kuzma airline. So far less horizontal mass sounds better in all instances. This does not hold true for vertical mass.

Interesting comments from DG as they relate to the Terminator arm. I have only seen pictures of it.

imo - it is not valid comparing the ET2, 2.5 and Kuzma Airline in this manner

Dgarretson is not comparing the ET2 & Kuzma. His post is quite clear - it is a report on the effect of running the Terminator with different horizontal effective masses.
At no point in his post is he comparing the ET2 and Kuzma tonearms.

Dover

Point taken - for some reason these comments from DG

08-18-13:
I've tried it with as little as 35gm horizontal mass and as much as 100gm-- approximating the range of horizontal effective mass from ET to Kuzma airline. So far less horizontal mass sounds better in all instances. This does not hold true for vertical mass.

Represented results and reference points to me and assumptions got made. This triggered a need in me to summarize some of the discussions that have been held here on this thread between the two tonearms. This is an unfortunate habit (summarizing) from my work career and the comments were not related to DG’s comments.

imo - it is not valid comparing the ET2, 2.5 and Kuzma Airline in this manner

bad wording on my part.

I certainly hope DG took no offence. I blame the summer heat.

Thanks for letting me ramble on and get off with only a warning – this time.

Hello Ct0517 & Dover, of course no offense taken. The discussions about the significance of variations in horizontal mass have been of interest here and in several AA and DIY forum threads. I have yet to try a really low-compliance cartridge on Trans-Fi-- which may change my current opinion that "less is more" w/r to horizontal mass. I've experienced this with a large number-high compliance MM/MI cartridges and a small samples of medium-compliance MCs.

I'd have to dig for the URL, but I recall that either Mark Kelly or Poul Ladergaard calculated the lateral stylus force applied by a linear tonearm as compared to force attributable to overhang and off-set in a conventional pivot arm. If as modeled, the lateral forces of a pivot arm(to which we must also add the tonearm's effective mass) are significantly greater than that of a 100gm linear arm, then this may suggest that a linear arm(whether 35gm or 100gm) cannot be faulted for its large lateral mass. Perhaps this is what F. Kuzma meant when he said that 100gm is "no big deal." In any case, I was not suggesting the relative superiority of any of the three very different linear arms under consideration.

Dgarretson.

I look forward to your tests on stiffer carts.

Also re pivoted arms, I argued inelegantly a way back that the offset angle on a pivoted arm has a multiplying effect on the effective mass as seen by the cartridge. That is, the cartridge is not expending all its effort in trying to rotate are arm but a vector of this force due to the offset angle. Then of course we have to take into account the asymmetrical nature of anti skate. This could be what Mark or Poul are referring to?
With these parameters at least, chalk up a big advantage to a linear arm.

Richardkrebs
the cartridge is not expending all its effort in trying to rotate are arm but a vector of this force due to the offset angle.

Actually it is the tracking angle that propels the arm inwards, which is different from offset angle. The skating forces are proportional to the tracking angle and tracking force. With higher tracking forces the skating force reduces. It also reduces with longer arms due to the reduced tracking angle. If you are tracking from about 2.5g with a 12" arm the skating force becomes very small, and if the tonearm is designed with breakdown torque taken into account at this point it is possible to run a pivoted arm without anti skate. Stylus profile also impacts the skating force. Ladegaards theory ignores these causal factors and assumes no anti skate is applied, therefore it is a worst case scenario and improbable in reality..

Conversely on eccentric records the high horizontal mass of a linear tracking arm will create tracking distortion. Very few records are truly round, and increasing the mass with lead on a linear tracker will increase the inertia of the arm in the horizontal plane and increase distortion on eccentric records due to cantilever flex. Thigpens' recommendations are that with records with an eccentricity of 1/8" a low mass pivoted arm will be superior.

Dgarretson - your listening experience that lower mass is giving superior results with the Terminator mirrors most ( actually all except for one ) of the users of the ET2 on this thread that have attained optimum sound quality from the correct application and tuning of the low mass/decoupled counterweight design parameters that the ET2 is based upon.

Hi Dgarretson – Does the wiring on the Terminator play a role in damping (stabilizing) the stylus ?
cheers

Hi Richard - are you up and running with the new pump yet?

Cheers