Finally had time to try Dertonarm's VPI template. It is very close the VPI jig. The stylus hit the stylus mark on the template exactly. I saw it was canted slightly with the stylus end of the cantilever closer to the spindle. I made the adjustment and am listening now. The cartridge is the Grado Statement1 on a VPI 10.5i arm. The LP is John McLaughlin's Extrapolation.
Compared to the VPI, the music sounds more open and the individual instrument's are more clear in the stereo mix.
I don't have any idea what Daniel's VPI template is based on but it sure sounds good. This is the setup I will be using with my VPI table. Thanks, Daniel. The only wish I have is to have an easier way to find the exact center of the pivot. I found the regular pin easier to "see" the center of the pivot than the reticule.
Overall, I am quite happy with the Uni-Pro. The led light is very useful and the setup makes it very easy to see the cantilever. |
Dear Lewm, and this is exactly what the UNI-Protractor does ... ;-) ...
Seriously, the UNI-Protractor works in exactly the very same way as the Dennesen, - which I have worked with for 25 years.
This discussion started by the reviews of the uNI-Pro by Downunder and Halcro was about the actual measurement of the spindle to pivot (i.e. mounting distance or P2S) distance which is not incorporated into the UNI-Protractor's design.
In the UNI-Protractor's set a stainless steel metric ruler with 0.5mm scale was included as a handy tool for the owner to check the P2S if one is curious. This however raised the question why it wasn't incorporated into the positioning arm - just like in several other templates on the market. This of course can't be an option due to geometrical reasons.
Originally I had in mind a super-precise P2S measurement device as a stand alone tool. To me mounting distance was rather a different topic as alignment and a pre-determined condition on most turntables anyway. As the UNI-Pro - just as the Dennesen to Baerwald IEC (Löfgren A IEC) - aligns to a certain geometry independently of the mounting distance, I originally saw no need for measuring the mounting distance (P2S). Some owners of the UNI-Pro did however find this to be the one shortcoming and thus I want to address the issue with an optional P2S-tool which can be incorporated into the UNI-Pro at wish.
It will now come as a relatively inexpensive add-on which can also be used as a stand alone instrument.
An option like the UNI-Scope - not mandatory at all for perfect function nor alignment with the UNI-Pro.
Cheers,
D. |
Dear Dertonearm,
I have not been following this thread, but as you know, I have a Uni on order. Please tell me, can the basic Uni that I will be receiving, without any of the extra and extra-cost items you are about to introduce, accurately cite the location of the tonearm pivot using the spindle as a reference? That's how I use my Dennesen and partly why I bought the Uni. Thanks. |
Peterayer, You may be interested in what I deed. My Kuzma
Stabi Ref. has just one armbase but because I own Basis
Exclusive phono-pre with two separate pres I wanted an second tonearm to put next to the TT. Both the arm pod and the tonearm are made for me by the Reed (www.reed.lt).
Thy produce those armpods on order. Ie according to your ownspecifications. On their web site you can see 'my' solution (by feedback) and the arm pod by the accessory.
Regards, |
Dear Peterayer, there is an overhang gauge coming with the UNI-Protractor set to measure direct spindle to stylus distance (overhang).
The UNI-P2S will integrate into the UNI-Protractor as well as can be used as a stand-alone-device and allows precise spindle-to-pivot measurement.
Cheers,
D. |
Dertonarm,
I apologize but I think I may have missed something in your thread. Is the P2S for measuring the pivot-to-spindle distance or the pivot-to-stylus distance (overhang)? Could your device be used to measure either?
I am considering a separate dedicated arm pod for mounting an additional arm. I would think that your UNI-P2S, if pivot-to-spindle, would be indispensable for this purpose.
Keep up the good work. I'm beginning to wonder what other devices you have up your sleeve. All this for improving analog playback just as I read from Raul (in another analog thread) that he thinks the best digital can now compete and even surpass good analog. (Sorry if that is a bit controversial to introduce in this thread) I think it is all about tiny improvements in accuracy adding up to real sonic gains in either medium. |
Dear Thuchan, yes I have a schedule. The UNI-P2S will now come as a tool which can easily be incorporated with the UNI-Protractor (without any alternation !!) as well as stand alone as a precision mounting distance measurement instrument for it's own sake.
It will be introduced next week (i.e. first week of May ).
Cheers,
D. |
Dear Dertonarm,
do you have a launching schedule in mind?
Best & Fun Only - Thuchan |
Dear Thuchan, dear Downunder, originally I designed the UNI-Protractor as a tonearm alignment instrument. Measuring P2S is a matter of tonearm set-up and should be done prior to any alignment (usually you have to drill a hole in an armboard and so the mounting distance is kind of "pre-determined" before starting any alignment).
That's why P2S-measuring wasn't include din it's design. I now realize, that including the stainless steel metric ruler kind of woke up the wolves....
In any case - I will come up with an add-on to enable precise P2S measurement with the UNI-Protractor soon. This will NOT need any alternation to be done to UNI-Protractor and will come with a precise manual and installation instruction.
It will be a 5-minute plug'n'play device.
However - please accept my initial concept, that in my - sometimes strange and weird - mind, P2S was not an integral feature nor request in an alignment instrument for tonearms.
I still think that P2S is a part of tonearm set-up.
But - I will address it due to "public demand" ...;^) ....
Cheers,
D. |
I was always thinking about how to combine my measurement suggestion with the Dennesson and also the alignment by the Uni-Pro. Therefore only using one tool!!! For me the quest is over! You may see the result on my page (last image)
Best & Precision Only - Thuchan |
maybe the simplest solution is to print an exact scale meter on the Uni-Pros arm and supply an extra transparent block using parallel lines and matching the layout of the Uni-Pro just at the spindle site . You may then put the extra block over the black round spindle positioning it exactly over the middle of the spindle and facing it towards the scale meter as I have tried with my Dennessen approach. You are then able to read the distance easily. No more Feickert, no more Dennessen necessary. Dertonearm may provide a modified Uni-Pro arm and the block as a substitution package.
Best & Fun Only - Thuchan |
Dear Albert,
you may get some comfort in changing headshells if you are using those ones with a fixed cart like the Fidelity Research FR-7 series in the same arm. This is among other reasons why I have one FR-66s on each Micro. Also the EMT JSD 6 Jubilee which I regard as a best buy for its quality and its wonderful sound provides a fixed solution.
The Ortofon RMA 309 allows changing EMT & Ortofon carts "nearly on the fly" not changing anything even not the weight in most cases.
Bu to be honest the real fun we have when "working on our arms and carts". Otherwise we cannot use our alignment tools resp. the Uni-Pro.
I also wonder why it shouldn't be possible to move the Uni-Pros arm to the middle as you describe it. |
Thanks Jazzgene and Downunder,
It's interesting to read all the first impressions as they begin to trickle in?
It seems there are some who like the full mirror whilst others may prefer a 'frosted' mirror? Personally, I never understood how to correctly use the full mirror in a parallax reflected mode so perhaps that would be an advantage?
As Daniel is now finding.......you can't satisfy everyone?!
Thuchan, who always strives for the best possible solutions, has devised a perfect way to utilise the supplied steel rule but his description is not as good as his photo of the solution (a picture is worth.........). Hopefully Eckart, you can find a way to post your picture?
I have been rethinking the steel rule comments and in Daniel's defense, there are many more turntables with 'fixed' tonearms than those accommodating changeable tonearms. I myself lived for 25 years with a Rega Planar 3 with a 'fixed' Hadcock GH228 so why would I worry about Spindle to Pivot dimension?
Of course in those days before the Internet Forums, I didn't even appreciate the importance of critical alignment?
And those of us who in fact do have adjustable tonearm mounting devices, would certainly already have a Spindle to Pivot measuring device already.
So I can understand Dertonarm's thinking here although something tells me that whilst the UNIprotractor 'arm' is not centred on the Spindle, there might be some mathematical formula which, when the micrometer is wound down to its minimum position, could still be used to check Spindle to Pivot dimensions?
Perhaps Daniel could consult with a mathematician about this?
This leads me to another question about the UNIprotractor.........if someone has a turntable with a fixed arm which had been incorrectly positioned by the Dealer or Manufacturer by say 2-3mm (which is very easy to occur), what effect does that have on the accuracy of the UNIprotractor?
Another question which gives me even more nightmares?.........if each arm is set according to a different geometry/alignment, how do those with cartridges mounted in interchangeable headshells swap those headshells between arms?
I certainly don't want to have to align each cartridge when I change headshells and then change it again on another one?
Life is for 'listening'.......isn't it? |
Dear Halcro,
After further engagement with the Uni-Protractor I can share your experiences. Especially regarding the "frosted mirror design". It is sometimes very difficult to hit the point. If I am using a lamp into the direction of the needle it helps a little to find the exact location.
regarding the P2S measurement I have made a suggestion in my answer to Downunder. At the moment I do think a two step approach, P2S measurement, then using the UNI , makes the most sense.
It is not a 9000 Dollar arm which comes in a 200 Dollar box, but you understand that this tool is designed for other purposes. Nevertheless I wish i had a wooden box to put in the fully build up Uni-Protractor just to take it out for usage when neccessary.
Best & Fun Only - Thuchan |
Downunder, I fell into the same trap as you, and you are completely right: The Feickert provides a comfortable distance measurement.
What I did: I fixed Dertonarms scale tool on the Dennessen, putting the black middle round over the spindle as a horizontal bases, and put the Azimuth transparent block on top running it against the scale (see last image on my page).
I am now absolutely precise on the distance and in the next step I do use the UNI-Protractor.
Of course you are right it would be fine to have it within one tool. maybe Dertonarm will consider a UNI-Protractor v2 combininig these capabilities.
Best & Fun Only - Thuchan |
I think Daniel added the ruler as a "estimate" tool and not for a precise measurement. If you look at the positioning arm, it does not go to the spindle so it can't give P2S measurement without a complete re-design.
I believe if you are very careful, you can get a very precise measurement of P2S with the ruler supplied, though. Use some CD cases to lift the ruler so it is completely parallel to the platter. Look at the ruler directly from above as well. |
Nice reviews Jazz, Halcro & Genesis. I received mine on Thursday. I said I would be honest and open, so here it is. Halcro, I especially liked your photo's and you gave me the rather obvious position in hindsight to place the led light on the inside of the tonearm. First up, the packing, quality and german engineering excellence of the package is there for anyone to see. First class. You actually feel that you are purchasing something of class. Issues for me first. Giving out a bendy small ruler for P2S measurement is a bit of a joke IMO, regardless of .5mm accuracy. You will be more than .5mm out on the P2S measurement given the inadequacy of the ruler. Given the entry price, a better tool should have been provided in the package like with the cheaper direct competitor, the Fiekert. It has an excellent P2S measurement device as part of the alignment tool. This may be my oversight, however when looking initially at the photo's and given that the alignment devices in competition are Fiekert I thought the positioning arm was also the P2S measure. Given P2S is measure is such a critical part of any alignment tool, that one was not provided is poor IMO. back to the review the instructions in the manual are very detailed and straight forward - excellent This device will take you longer than the Mint or Feikert, however you IMO get much better precision than the Feikert. The Feikert is poor with its generally fat lines painted onto steel compared to the Uni-tractor. The Mint has always been a poor cousin to the Wally tractor and the uni tractor with its lazer etching is a lot better than the Mint's lines under the mirror approach. It was easier to align the stylus point onto the exact lazer dot on the uni template compared to either Mint or Feikert. That is the beauty about the lazer etching. I, like the others struggled a little bit with the two etched lines on either side of the middle line, in how they curve slightly due to the magnification. like anything, after a bit of practice it got easier. Once that was done, you were complete. two points vs one point. Frankly, with the Mint. If you aligned the initial null point perfectly, I always found the 2nd one lined up as well. So the Uni-tractor having only one meassure point is no big deal, you just need to concentrate on getting it correct up front. The Azimuth tool was cook and very good to use next to the tonearm to see how level the tonearm was. - non standard uni-templates. I guess a lot of people are interested in the specific aligment templates. to quote Daniel the EA-3 template is based on the EA-3's geometry, but a bit
"optimized" by myself - so kind of "my brew".
- same for Graham and Ortofon - very slight corrections, but better
distortion figures than manufacturer's specs. I used the Exclusive EA-3/10 alignment template to compare with the Stevenson alignment from Mint. Yes, I know, not really a fair comparison. The Stevenson vs Stevenson will come later. I buy mostly modern LP's but many have music right to the inside label. I much prefer Stevenson/VPI type alignment than L or B. Mainly due to the fact that the inner 3rd of any LP(which is getting smaller and smaller with each revolution)to my ears has the most obvious distortion compared to the rest of the LP. Overall the slight increase in brightness on the 1st 3rd is more than compensated with the better sound of the last 3rd with Stevenson. Right, my listening bias are out of the way. The EA-3 alignment was more relaxed in the first 3rd vs Stevenson and as good ads B or L from memory. It was better sounding than either B or L in the last 3rd to my ears. Not quite as good as Stevenson, but overall something I can live with. I'll go back to Stevenson in a couple of weeks. My Mint tractors will be soon for sale on audiogon. The Feikert I am afraid cannot be sold ATM as detailed above. I believe the adequate P2S tool should be part of the Uni-Tractor price given its importance for correct alignment, not offered as it seems to be next week as an additional extra. I would be interested if anyone else shares my view on this or I am out of line. Overrall a 1st class product is the Uni-tractor and oozes quality. |
My Uni-Protractor had just arrived. Although I am not yet in position to put to use, may I offer a quick initial impression. As a watchmaker for many years I developed an utmost appreciation of finely crafted precision tooling. Overall, I am very impressed. The price outlay is very small compared to my, or many others, TT setups. I feel very good costumer service here, and that this is just a beginning for Dertonarm. |
Here is my review of the Uni-Pro. Received it in great shape. Well packed and bomb proof. I liked how you packed the unit. I did notice a few freebies such as the ruler and the light?
Upon setup, I noticed a few things that could be improved.
1. the center pin is a little short for my liking as my Dynavector has a lower pivot piont. I think a longer pin would work much better and would not hurt the design.
2. like Jazzgene said, The lines on the centering device is very difficult to see on lighter/shiny tonearms especially the FR66s and my DV507. I believe should the lines be anothter colour instead of white would be much easier to see.
3. Numeric markings on the acrylic arm like the Feikert would be a bonus.
Now to the strong points.
This thing is built like all German made stuff. Serious, tough and the word precision written all over it. Looking into the magfier proved an easy task on this system as it has a large enough lens.
Upon checking my setup, I noticed my alignment off by a little. Correcting it via the Uni proved easy enough.
Now to the sound. The setup (DV507) after using the Uni was more solid and focussed. It also proved itself as after the adjustment as there was slightly less surface noise (quieter) and less grain in the music.
So far this is the first tonearm I have setup with the Uni. Will do my other tonearm when I get time this weekend.
Now to the milloin dollar question.....Is it worth $800? I will leave it up to you. If you are like me who regularly sets up turntables, It is definitely worth it's asking price. Also if you own a resonably priced analog rig and plan to go deeper into analog, You owe it to yourself to get one of this UNI's and setup your own turntable instead of getting someone to do it for you. |
I am very happy that you can change the color of the reticule. Thanks. Great customer service. Looking forward to getting it. |
Dear Jazzgene, good point here ! On black colored finish tonearms the UNI-Pro's reticle will be best as it is, but I will pick up your suggestion and will have a batch of reticles w/black hairlines made in 2nd production run. I will provide a reticle with black hairline once the 2nd production run is ready to ship, which will be end first week May.
Cheers,
D. |
I enjoyed your review.
For me, I want to do a better job finding the center of the pivot on the 10.5i arm with the Uni-Pro. Perhaps the reticule can be of a different color? Since it is white, it is a bit tough to see against the silver of the 10.5i arm. This issue is not limited to Uni-Pro. Feickert and Clearaudio also has this issue. The center rod is too skinny for the center hole of the 10.5i arm pivot. At least the Uni-Pro provides a reticule. |
Dear Henry,
thank you for this throughout comprehensive and dedicated review.
Please allow me to briefly address the points of concern in your post/review about the UNI-Protractor.
* MA-505 / Grace 940.....
While both tonearms do indeed share the same overhang, mounting distance and effective length, they had different destinations from their designers.
Hence the two templates have very different null points.
Consequently the micrometer scale must show different values for these two templates too.
The Grace 940 follows an unusual alignment curve with VERY little distortion in the 2nd half of the record.
The MA-505 does follow (according to it's designers) rather the Stevenson DIN calculation. I have a bit "optimized" the MA505 calculation alignment, while letting the Grace 940's alignment stand as it is.
* ruler as P2S......
Well this was included as a handy tool ( and not mentioned in the initial Audiogon listing, but added as a "freebee" later. This is just intended to serve as a quick check whether the mounting distance is correct. I thought it to be a nice add-on, as it offers ( not common ...) 0.5mm scale.
Please note, that this can not be incorporated in the positioning arm, as the positioning arm does not aim direct over the spindle.
Since the UNI-Protractor was designed to offers precise alignment for all mounting distances, it's positioning arm can not aim direct over the spindle and must be variable too in it's distance to the spindle for different null-point-alignments ( please see Dennesen's original patent for further details and perfect explanation of the geometrical background ).
BTW - "my" P2S-tool - the UNI-P2S - will be introduced (finally) early next week.
This however will be much too much for most and is only a suitable tool for professionals who do set up tonearms on a daily/weekly basis and want the most precise.
* "full mirror" vs "frosted mirror"
That may be a matter of personal preferences - to my eyes the full mirror parallax is much better, as it allows for clear view of even the most minor declination (especially the helping lines left and right wing of the cantilever center line).
* geometry - name engraved on template
Those templates following any of the "standard 3" (Bearwald/Löfgren A, Löfgren B or Stevenson ) have been named so.
All the others do either follow their manufacturer's geometry or have been re-calculated by me. In those cases where I have recalculated a specific tonearm's alignment, I have named it so (i.e. FR-64s 231.5 D.B.) as this most often goes hand-in-hand with a mounting distance different from the manufacturer's specifications.
If my "correction" was rather marginal (i.e. MA-505) I have not left my signature.
Again - many thanks for your time and effort to supply this review !!
Still worth a smile IMHO is the fact that the birth of the UNI-Protractor was initially provoked by the deleted "FR-64s geometry" - thread of past early winter.
Cheers,
D. |
When I first tried to actually use the UNIprotractor, I wished I hadnt have volunteered to do a review. No matter how hard I tried, I couldnt see the stylus?! The package from Germany arrived many days ago and at first I was slightly disappointed at the appearance of this plain brown cardboard box. Surely a white or black box with some unique graphics was warranted to encase the high-tech machine-like tool within? Of course that would have increased the costs and Daniel did not at first know, how many of these machines he would sell? Once opened, the contents were convincingly revealed to be well packaged and a few surprises, such as an LED high-powered lamp and a pair of soft white gloves were included. Prior to its arrival, Daniel had Emailed the coloured Instruction Manual together with the appropriate micrometer settings for 5 of my 6 arms and let me say that with the exception of the Copperhead, these instructions are better than those which came with all my tonearms. But back to the turntable. I had easily assembled the UNIprotractor as detailed in the Manual, and had it positioned on the nude Victor TT-81 with the Fidelity Research FR-64s tonearm as the first patient. This was not a fair test admittedly, for the Dertonarm recommended geometry for the FR-64s does not follow Baerwald or Lofgren and the spindle to pivot distance recommended by the manufacturer, is not followed by the UNIprotractor. I had already adjusted my spindle to pivot distance for the arm to be 231.5mm instead of 230mm and had aligned it via the Feikert protractor by utilising its overhang alignment rather than its Baerwald alignment. This also required a twist to the tracking angle but I didnt have the correct null points to accurately gauge this angle so I knew my set-up was inaccurate. The cartridge was a MM favourite of mine
the Signet TK-7e mounted in the FR-3 headshell and for the life of me, I couldnt see the stylus, head-on, through the magnifier. After developing mild backpain crouching for over an hour, I decided to switch off the lights, have a coffee and a well-earned rest. During this interlude, I pondered whether Dertonarm had erred in his design by using only modern LOMC cartridges rather than my preferred vintage MMs which had their stylus tips generally tucked well back from the fronts of the cartridges. Had I just purchased a white elephant I wondered as I gazed at the trees framed against a deepening blue sky? After an hour, I returned to the turntable, switched on the LED lamp and peered once again through the magnifier. Could it be? Was that it? A stylus tip? I grabbed my hand-held magnifier and held it behind the fixed magnifier and there I saw it
.a clear stylus and its black cantilevered shaft framed against the mirrored gridlines of the UNIprotractor :-) Most new tonearms are somewhat intimidating on first set-up but once familiar, they become easier and eventually simple to adjust. The same must be said for alignment tools. The Feikert was initially difficult and is now childs play as is Yips MintTractor and the WallyTractor. Once I knew what I was looking at and for, it became easier and easier to use the UNI protractor until by the fifth arm, I was laughing. The Signet TK-7e was out by nearly 2mm and its tracking angle was also off. Easily fixed using the UNI. My previous defacto set-up tool of choice has been the Feikert which is a one-point devise like the UNI. Whilst I use it to set spindle to pivot and overhang (based on Baerwald), I like to use the Mint to adjust the correct tracking angle at the Null points because it is so easy to see compared to all the other devices I have. The Feikert came with my DaVinci 12 Ref Grandezza tonearm and whilst one face of the white Tractor Disc is marked as a Universal template, the other face is dedicated solely to the DaVinci. As such, you would expect it to be ultra accurate and so it was. The UNItractor proved that the DaVinci was as good as you can get. With the other arms and various cartridges, the UNI showed some to be ALMOST perfect, whilst others required adjustment. None was perfect like the DaVinci, and having the UNItractor prove this fact, I trust it implicitly for the other arms. So is the UNItractor worth its price? If you have several arms and/or interchangeable headshells equipped with multiple cartridges, I would say yes. If you have only one arm and want the most accurate tool available to align an arm/cartridge then again I would say yes. Is the UNItractor perfect? No, I think it can be improved
..and quite easily. Firstly, being a one-point device rather than a two-point arc protractor, the spindle to pivot dimension is critical. There seems little point IMO, to have the accuracy and tight tolerances of the UNI if you can be 2mm-5mm out in your spindle to pivot distance? The best device I have seen for measuring this dimension, is the adjustable Feikert aluminium sliding beam and locator. This is rigid and super accurate but what does the UNI provide?
a floppy steel rule. There is simply no way that anyone can come close to accuracy with this means other than by fluking it. And this is so silly because the UNItractor already has a device which is nearly as good as the Feikert. The locating device which locks onto the spindle and hovers over the tonearm pivot could easily have a scale on its base which can measure the spindle to pivot dimension. I know that Daniel is soon coming out with a proper measuring device but this IMO is unnecessary. Another improvement I could suggest is that the mirrored templates which click into the protractor for each different arm, should be a frosted mirror like the Mint instead of the full mirror which is more difficult IMO to see clearly. A further suggestion I have is that the selected arm geometry should be engraved on these mirrored templates. At present one does not know if one is setting the arm for Lofgren A, B, Stevensen or something else as Daniel pre-selects what he considers is best for each arm. In some cases that is simply the arm manufacturers recommended geometry so that for my Grace 940G and Micro Seiki MA-505S which both have the same effective length and overhang, Daniel supplies two separate templates. Apart from these easily incorporated improvements, I have nothing but admiration for Dertonarms UNItractor. A serious device for the serious analogue audiophile. UNIprotractor |
Dear Thuchan, .. and your RMA 309 features no antiskating device at all - for good reason.
Cheers,
D. |
Maybe all said about antiskating. Nevertheless it was quite an exiting expedition and I am still admiring my Ortofon RMA 309 how it manges all these requirements. No I don't need an answer - not this time and not here.
Best & Fun Only - Thuchan |
Dear Jazzgene, serving as the advocate of mechanics here let me briefly add that skating force does NOT increase with increased VTF.
Why so - since friction is of course direct related to pressure (here: VTF) ?
Because the friction increases on both groove walls - thus the relation of the side-wards pulling skating force to the downforce becomes less ( for those preferring the illustrative real-life picture: the resulting force of "your" sidewards pulling "wife" ( mine rather pulls on the same end of the rope as me .... ) becomes ever less dominant the higher the pressure of your "friend" nailing down the stylus .....).
Not my idea - it's simply mechanics here on our planet under the dreadful influence of gravity.
That's why in general skating force becomes negligible with very high VTF (talk about Ortofon and old SPU's running with 4 - 5 gr. VTF).
If you draw a force vector diagram it will nicely illustrate the point.
The skating force is a product of several sources.
However - the portion which starts it all comes from the breakdown torque of the offset angle.
That's the reason why pivot tonearms with full lateral balance ( direct addressing the static breakdown torque where it originates) and long effective length ( = smaller offset angle ) do display less skating force to start with. Now add higher VTF and the skating force - as a resulting force relative to forces aiming in different directions - becomes less and less with increased VTF.
In contrary this the reason why 9" tonearms working with low VTF and high compliance MMs do of course need anti-skating to address a problem VERY dominant in their particular situation.
Skating force in analog playback is diametral inverse to VTF.
No question about it, - anti-skating is desperately needed with shorter tonearms running with high compliance/low VTF cartridges. Here it resulting side-force is comparatively strong.
Influenced by many parameters all working to add to the skating force.
A longer effective length tonearm with ever smaller offset working with low compliance cartridge and high VTF is the exact opposite situation. Here all corresponding parameters do work to ever lessen the resulting side-force of skating.
BTW - how about starting a "skating - anti-skating"-thread ?
Cheers,
D. |
Thuchan
I often sweep things under the mat.... Most people probably do too. Especially the hard things, like precision in areas where it is hard to be accurate or measure reliably - antiskate is one, and, for me, setting cartridge offset is another.
I was playing with an angle protractor this evening and trying to see how repeatably I could measure an angle. Where it was possible to physically set the protractor against both objects it was easy, but by eye maybe within 0.5 degrees.... that is one place we need precision.
|
Jazzgene you said The thing is if the anti-skate force differs from the beginning to the end of an LP, how can a constant weight compensation like the VPI weight on a string work correctly on the entire LP? It can't, I would think. If your antiskate is the JMW 9 then the force will increase as the arm moves towards the centre if the little arm with the weight is horizontal when the arm reaches the run out. if it is literally a weight on a string, like the old SME, it can aso be set to apply an increasing or reducing force depending on the angle it makes with the arm, though this doesn't apply if the string run round the diameter of the pillar and the radius it is acting at doesn't change. Check the output wire and make sure it is not counteracting or adding to the antiskate. You can use headphones and a test record to check for distortion on one channel more than the other. If it distorts on the right, you need more antiskate.If the left, less. If it still distorts on the left with no antiskate, the wire is pulling outwards. Using a greater VTF stops the distortion by nailing the stylus in the groove, but it also increases the skating force because friction is proportional to VTF. If this was not so, our cars would go faster as the braking force increased... |
Dear Mesal, John stated (04-11-11) 'It would be possible to
to design a cam system given different leverages so as better to follow the average variation...' Well this was
the Sony solution as I mentioned before. One get the impression that the issue is rather avoided then solved by
adding more(confusing) variables. But looking to the actual constructions of the antiskate mechanism one can conclude that not much thought is implemented. And those are all mechanical issues that can be measured as well as covered by Newton. Or so I thought.
Regards,
Regards, |
Hi John_Gordon, like it what you you said: we can`t just sweep it under the mat... this is also the case regarding precision! we don`t like to listen under the mat and you don`t do it too.
Best & Fun Only - Thuchan |
Dear John,
Thanks for your response, I appreciates. |
Mesael Sorry. I said The angle changes towards the centre not varying much, but under 7cm radius, the closer to the spindle it gets, the greater it becomes, until at 0 it is a right angle.. What this means is that the inward force trying to rotate the arm stays more or less constant within a few percent reducing slightly following the tracking error curve of the arm (not the tracking distortion curve) which varies across the record. Depending on the overhang used and the arm effective length, at the inner null the force starts to increase rapidly. So it would appear that the ideal would be to follow this curve, reducing slightly then increasing. However, it has been shown that there are other factors which increase the friction force as the radius decreases, which would skew this result and make it more likely that the force should at least be constant then increase, or even gradually increase all the way across the record When I designed my arm that's what I did, as I thought that, like tracking distortion it seemed to be worse towards the inner grooves, and less of an issue further out, and should be weighted that way. But it was all "suck it and see". So, really, a tonearm should perhaps give the user the option of trying different things. The actual amount of antiskate needed is very much dependent on stylus profile and downforce. With enough downforce the stylus will never meet a modulation large enough for it to lose contact with the outside wall, or even throw it up out of the groove. However there will still be unequal forces on each side of the groove unless there is some kind of compensation. As Dertonarm says, a longer arm has less skating force than a shorter one. But it is still there, and it has to be dealt with somehow - you can't just sweep it under the mat.... |
Dear John,
You didn't answer my question, or might missed it. How should anti-skate work in a pivot designed tonearm ?
From outer groves to inner groves :
1. decreasing
2. increasing
3. decreasing then increasing
Or none of the above.
Regards, |
Dear T_bone, yes, different alignments do alter the shape of the tracking error curve. However - it is always a bundle of effects which you can't actually isolate from each other and their dependences. The more "flat" a tracking error curve becomes, - it goes hand-in-hand with longer effective length and less offset angle. All these do influence the skating force. A zero offset angle (tonearm and cartridge body ..) would result in zero breakdown torque and thus any remaining skating would just be a function of friction due to contact area size. That would diminish even further with increased VTF. But even in a zero tracking error point - i.e. "null point" (strange blend of german and english here..;-) ... ) there is still the breakdown torque of the tonearm itself as the ever dominant source for skating.
You are right - a skating force "curve" across a record's groove will never be linear. Not with a pivot tonearm ( not even with the Thales).
The groove's radii change - so does the friction on the inner groove's wall. The tracking error decreases and 2 times and increases 2 times during the groove.
IMHO the most suitable way to handle this practically was always the same: - 12" tonearm w/low offset angle, low compliance cartridge with high VTF, lateral balanced pivot tonearm.
In other words - all measures taken to minimize breakdown torque so to minimize the evil at the source. Better to minimize skating to a value negligible then to fight a constant war with lots of friendly fire (anti-skating...) and no aspect to win.
That way of mine does of course limit the choice of cartridges and tonearms.
As my prime choices in both categories do however qualify in all points to this schemata I am kind of lucky..... ;-) ...
In any case - it is a path as suitable as some other.
It just suits my personal way of addressing problems at the source rather then seek painful cures for situations which have already evolved way past practical solutions.
Cheers,
D. |
@John,
I might install the VPI after market Anti-skate weights again just to re-confirm what I heard the first time.
The thing is if the anti-skate force differs from the beginning to the end of an LP, how can a constant weight compensation like the VPI weight on a string work correctly on the entire LP? It can't, I would think. |
Regards, T_bone: If I understand your point then an alignment with zero overhang would result in all relevent forces coming into balance at the spindle, progressively increasing overhang would bring "stasis" at incrementally greater distances from the center?
Peace, |
Perhaps it might be a good idea to go back to basics. There are two aspects to this issue. One is to acknowledge what the force is and how it originates. Second to see how it manifests itself on a record deck.
While we might call it antiskate, or bias, or whatever, the force which pulls the arm inwards is not specific to tonearms. It can apply in any situation where there are two forces opposing each other.
To illustrate the simple example of a linear tracker. (Those of you with linear trackers can start practising your smug grin.)
Say you hold one end of a short rope. You are the Tonearm bearing. You put a conical blob of blutak in the middle of the rope - the Stylus. Your wife holds the other rope end. She is Friction.
Friction acts on the Stylus by pulling it along the groove in a direction directly opposed to the Tonearm bearing. It reacts by holding on and pulling back. The rope is straight. The Stylus remains unmoving in the middle. As friction moves to the side, Tonearm bearing follows every move (hopefully).
Now a Pivoted arm.
Friction takes a different tack. She pulls at an angle. Tonearm bearing reacts against Friction. It is immovable. It holds on to the Stylus. but the rope wants to straighten, and Stylus will be pulled sideways, unless......
Help arrives. Another pal called VTF, stands on the Stylus. now it's harder for Friction to pull Stylus sideways. Then yet another pal, Antiskate, comes in and pulls the Stylus in a direction which stops the rope straightening, just enough to stop the Stylus moving without pulling it in the opposite direction.....
Ok, this is simplistic, but relevant. First, note that we have no mention of cartridges, only the stylus which is simply the name for a point on our rope. The angle we talk about is the angle formed by a line from pivot to stylus and stylus to groove. Which is not quite the same thing as cartridge offset.
Forget about cartridge offset for the moment and just imagine your arm with no cartridge, just a sewing needle on the end where the stylus would be, and then follow its arc on a record. Follow it beyond the inner groove, beyond the label, beyond the spindle, and out the other side. See how the angle between pivot, needle, and groove changes. Think of the rope story and in what direction the arm will be pulled. The angle changes towards the centre not varying much, but under 7cm radius, the closer to the spindle it gets the greater it becomes, until at 0 it is a right angle..
That is the basis of the antiskate issue. Does it exist as a force. It exists, yes, it definitely does. But why some people prefer no antiskate, that is for them to say. My arms had an antiskate mechanism, using lever and thread, which allowed for varying the force, and the ratio to some extent across the record, or it could be removed completely. But it was not any more sophisticated than that (It could even have been used to apply a reducing force like the Morsiani,though I am not aware anyone ever did, and not a negative antiskate as in their example of the blank disc; I think there's something wrong there.)
It would be possible to design a cam system given different leverages so as better to follow the average variation, though not the instantaneous.
Whether you can adjust for it totally and in every way, I doubt. As there are many other factors involved in the friction calculation. Some people are more sensitive to its effects than others. Personally, I always tried to compensate for it. I was concerned with its effects on imaging, soundstage etc
|
DT,
I would have figured that different alignments altered the shape of the tracking error curve (this is indeed the critique of using a Stevenson vs a Baerwald - that the tracking error curve is "worse" than the Baerwald over the whole of the recrod) and/or tracking angle curves as functions of radius, even if ever so slightly. If they did so, would the skating force curve not change as well? |
@04rdking
It's okay if you don't understand it.
The Uni-Pro allows me to try out different alignments. I just didn't like the Lofgren IEC compared to the VPI. I will try the Baerwald IEC and the VPI specific alignment later this week. Perhaps I'll find one of them preferable to the VPI alignment.
Oh, I also want to add that the Uni-Pro is much more precise than the VPI jig. The VPI jig has a certain amount of play between the jig and the metal piece that moves to contact the pivot base. The parralax effect can throw you off on the vpi jig as well. |
Dear 04rdking, please read Jazzgene's full post - he did not like Loefgren B IEC (which is a standard calculation ) and will try the special VPI-template supplied with his UNI-Protractor and the Baerwald/Loefgren A instead. It is a choice of alignment-options - not of the alignment instrument.
Cheers,
D. |
To Jazzgene,
"To note, I did not like the sound of Lofgren IEC and reset my cartridge to VPI's own jig which has a sweeter timbre and less harshness on grand pianos."......
"Is Uni-Pro worth the 700 bucks? That would be up to the individual and their wallet. For me, it was a great purchase as it makes setting up my cartridge so much easier with no fuss. So a yes for me......."
So, you say it's worth the 700 bucks, just to go back to your old original alignment with the supplied jig......
I don't understand that....... |
Dear T_bone,
a correct calculated alignment curve - much to my regret ... ;-) ... - has practically almost zero influence on the skating force. Unless the alignment curve is really VERY bad and raises to astronomic values.
Cheers,
D. |
@Ct0517
Yes, I find my VPI 10.5i arm to be best without a twist in the cable as well. |
Dear Timeltel& Mesael, Those are HUGE confusions I should think. On an 'blanco' LP or an LP without grooves one can
observe the acceleration of the arm toward the spindle if no antiskate is used. Ie the centripetal force as Timeltelt stated can be seen in action . The Morisiani story is the opposite one. Ergo it is logicaly as well as physicaly impossible for both to be true. However those
forces should be the basic one for all of us to understand.
Regards, |
DT and Timeltel,
Given the nature of how the tracking angle changes over the course of the record (for any arm), I would expect the skating force to fall on its way inward and then start to rise again as it moves past the peak tracking distortion area between the null points. The changes in friction coefficient (which will, of course, depend on stylus shape) would affect this, as would any changes in VTF as the cart/arm track the record. Different AS methods should actually affect the VTF 'curve' (as a function of groove radius), as should the fact that the VTA/SRA angle will actually start to get steeper on the way back in. Kind of interesting to think about...
I am assuming that one's choice of alignment (or perhaps more particularly, the location on the record of the peak tracking error between the null points) will have some effect on how much skating force ceases to tail off in the last part of the record...
I've just given myself more stuff to muddle through, obviously... |
Regards, Mesael: Thanks for the link to "morsiani". The thought of skating forces increasing towards the spindle was not consistent with what little I understand about Newton's concept of centripital force.
Peace, |
Dear Daniel, why don't you get a cup of hot milk and get a good sleep also?
Ooops! I forget. I promised not to ask anything. |
Dear Mesael, Morsiani is right.
He is right in that the skating force get's lower/less towards the inner label - i.e. decreases with decreasing groove radius.
As the contact area towards the inner groove wall decreases with decreasing radius, so does the friction - ergo the related skating force.
So Morsiani's concept does address the problem rather smart.
Cheers,
D. |
Dear Nandric,
Not so fast. I'll show you examples of tonearms.
Anti-skate from outer grooves toward inner grooves:
Constant : Clearaudio Unify, and simple counterweight
with string
Increases: Clearaudio Satisfy, and those using spring, and
most of magnet design
Decreases : Morsiani.
Here's the link :http://www.morsiani.it/
So, which one is correct or none of the above ?
I'll wait for John. He's a designer,and seems knowledgeable.
Cheers, |
