Dear Lewm: I owned the DV-505 and its a design that I respect a lot becaus e is unique, good for Dynavector.
You are right almost all japanese tonearms came with set up specs based on Stevenson.
When I try to mount my first cartridge on it I don't put to much attention to that fact and mounted according with the protractor at hand and I have trouble because the offset angle then I was aware of Stevenson and that's how I use it for some time but I changed to Löfgren B twisting the cartridge as you said ( I don't use it the Dynavector headshell and I can't remember wich ones I used because was years ago. ) and with the XV-1 mounted in that way I achieve better results that with the Stevenson alignment and that's the way I used. Maybe I could be wrong but that passed so many years that's dificult to be sure about. Yes, that tonearm conforms as no other tonearm with Stevenson.
In all audio alternatives exist trade-offs and perhaps those trade-offs " sounds " better for me. I don't mounted MM/MI cartridges down there but only LOMC. Unfortunatelly I don't have any more to test it again.
Regards and enjoy the music,
R. |
Btw, interesting: could you link your VE post to my email?. You know I'm willing to learn always.
Thank you.
R. |
Dear Raul, I have a few protractors mainly because I am still trying to find one that I really like. Personally, I like Mint protractor the best as far as ease of use, mirror surface and all. It is a lot easier to use for cartridges like Koetsu, Air Tight and Kiseki. However, now that I have 4 arms and most likely there will be more in the future, I don't want to keep buying new Mint protractor every time so I start looking around for universal protractor. I think Feickert is great and it has 3 geometries to choose but its finish make it harder for me to use on the 3 cartridges mentioned above. Clearaudio is fine but it has only one geometry with 4 IEC options. I figure since I spend all these moneys on cartridges and arms, why not experiment a bit more with various protractors if it may make a big enough difference in setting the arm/cartrige properly.
I am thinking of trying SMARTracker just because it seems that on the usability side, it is more well thought out that other protractors and seemed to be one that was really designed by end-user for user. It may not be more accurate than Feickert but at the very least, it would be more user friendly, I would guess. |
If I can find it, I will. I actually attached the post explaining my observation to a thread where the OP was talking about the question of having to twist the cartridge in the headshell, when he was using some other vintage Japanese tonearm with Lofgren or Baerwald alignment. At that time, I was just starting to use my DV505 and was not so happy with the sound, using Baerwald (with the necessary "twist"). He claimed the twist caused no problem, but I then found that protractor on VE and re-aligned my cartridge using Stevenson. There was a big and obvious improvement in sound. As mentioned, this may be especially relevant to the Dynavector tonearms, because the vertical pivot is so close to the cartridge. I believe the vertical forces on the cantilever would be asymmetrical, if the cantilever and the vertical tonearm pivot are not aligned (another problem in vector algebra), and this may be the cause of the distortions I heard. Just a guess. I don't know whether the principle should be applied to all tonearms in general. |
Dear Suteetat, I own 12 tonearms but use 'only' three of them. The Triplanar and the Reed 2A on my Kuzma S.R and the FR 64 s on my Sp 10. I also own some 'universal protractors' but when I got my first Mint LP I was 100%sure when I ordered the other two. Whatever the next one may be for $100 there is no contest in my opinion.
Regards, |
Dear Raul,
I have my SAEC WE 8000 quite a long time and will not sell it - never!
I will not repeat arguements on our discussion. You had not the best experiences with the SAEC or the FR-66s. So which tonearm "will beat" these two old designs from your perspective? And did you go for some better designs in your system? |
Dear Thuchan, I am really sorry for you but Daniel obviously love me more than you. However I like to think that my ingenious comparison between 'iron horse and locomotive' (aka the usual headshell versus Arche) moved Daniel in such a way that he decided to give me a present...
You as the owner of a company are of course familiar with the so called 'intellectual ownership'. When Raul refers to 'his' pre-amp, 'his' tonearm ,etc, 'his' , he rarely mention his employee Guliermos (or similar) who is actually the technical guy behind the products mentioned.
As you know the intellectual property is of the company and not of the employees inside the company. As Raul told us himself he managed to change some fuses, caps and resistors on his own. Well I am sure that my aunt Natalija in Serbia is also capable to solder such parts with their values writen on their 'heads' in whatever component. You can observe the same capabilities in the speaker thread. Unbelievable how many speaker experts are there, capable to discovere 'cheap wire' and/ or 'capacitors' in any speaker whatever. It is like this : 'Heureka'!: cheap wire inside! No wonder Nordost get rich with such experts.
Regards, |
Dear Nandric, you may be right regarding mint protractor.
I think I will try SMARTracker for a little while. At least I want to spend a bit more time experimenting with 230 vs 231.5mm on FR64s and once I made up my mind, then I get mint.
For FR66s, did Dertoarm have alternative P2S distance as well or only the FR's spec of 295mm only? |
For the FR-66s....Dertonarm is happy with the 295mm P2S distance.
For the 231.5mm P2S distance on the FR-64s.....be sure to amend the Overhang to 14.5mm for it to follow Dertonarm's geometry?
You cannot use any regular protractor for this....but the old Feikert Universal had an Overhang measuring scale. |
I asked Daniel (Dertonarm) about the 'geometry' of all those FR-7 versions. He still swears by those 'antiquity' while his answer surprised me very much. The stylus in
those huge headshells is not at the same distance by all of them. So, probable, even Dertonarm was/is not able to get the right geometry for his 66/ 7 (x) combos? If I was an Aussie I would inform by Daniel about my own specimen. But the most curious thing is that my FR-7 stylus follows exactly the curve on my Mint protractor made for my FR64
with 231,5 mm P2S distance. |
That's interesting information Nikola.....about the FR-7 cartridges.
Of course......if you one were to purchase Dietrich's new Axiom tonearm........one would be able....for the first time.....to adjust the Overhang for its correct geometry.
Although I have always liked you my Slavic friend.......I have never before appreciated your deductive mind?
The invisible Guliermo who is really the 'Technical Brain' behind the Essential Phono/Line Preamp and also the (in)famous tonearm and cartridge which are now......"not for sale".......?
Has there been a divorce with his erstwhile partner Raul?
The rumour mill is churning.......... |
Dear Henry, First of all we live in the so called 'global village'. While Germany is much nearer to me, Mexico is not at some far-away distance. Besides we have the internet
so one hears something or other. Regarding my 'deductive'capabilities you need to (re)read my post. Those are pure legal arguments based on the property laws.
If there is no logic in those laws than I am not able to see why you should blame me for this fact? If it is a fact. However I should provide more info about my beloved aunt Natalija. Uncle Boris (her husbend) got, according to his own story, the Russian oil capacitor of 3,7 mF value from Medvedev personaly. But my aunt Natalija soldered this cap on his tweeter.
Regards, |
Addendum, My aunt Natalija was the former employee by the
former 'E.I' (electronic industry) in the former Yugoslavia. |
Dear Nandric,
how old is your aunt and would you describe her as beautiful and eager to invest in an adventure? |
I know this Thread is about the FR-66s, but the FR-64s was introduced into the discussion and because its geometry is different to that of the FR-66s......I feel it needs some elaboration:-
Recommended for FR64s: 231.5 mm P2S, 14.5 mm overhang and 20.5° off-set angle.
This will give a very good tangential curve with very low maximum as well as very low average distortion figures in the last 2/3 of the record. For the last 66% of the groove this tangential curve outperforms Baerwald and Loefgren in any version by a very good margin.
With this geometry, the FR64s' tangential curve becomes very similar to the FR66s' original tangential curve.
This tangential curve honors the FR64s' original geometry - i.e. there is no additional breakdown-torque implied. |
Would the same geo suggested for the FR64s work for the FR64fx? More specifically I'm thinking about optimum geo for the FR64fx with an SPU. |
Halcro, I am very clueless about this and I am not quite sure what to do with the information that you give. I think I need a remedial study on this!
Came with my FR 66s arm, there is a paper protractor, is that the FR66s original tangential curve/geometry that you mentioned in the above post? I guess I need to give that a try. |
Suteetat,
I know it sounds very complex and most users do not really get involved with Overhangs and Off-Set Angles.
To make it easier for you....I think you can go in any of three ways:-
1. Use the FR recommended P2S Distances for both FR-64 and 66 arms and set the geometry for Baerwald according to any accurate devices you have.
2. Use a device like the Universal Feikert Protractor to set both the P2S Distance and Overhang of each arm. This is all you need to do to have the correct geometry.
3. Purchase the UniTractor from Dertonarm which will come with the correct Templates for both arms.....and any other arms you may have or may buy in the future. |
Halcro, thanks for your help. I am already doing No1 at the moment. My Feickert NextGen protractor does not have correction for overhang as far as I can tell. Just set P2S distance and choose geometry and that's about it.
A bit of a bummer as I chose to order SMARTracter rather than Uni-tracker (along with Arche headshell) just a few days ago. Oh well... a friend ordered Uni-tracter so at least I will have a chance to try it and see how that go. |
Dear Henry, I am a bit puzzled about a recommendation for a specific headshell offset angle to go along with the recommended P2S distance and overhang for the 64S. In the case of headshell offset angle, isn't one "stuck" with the built-in angle? In other words, I believe that both tonearms are S-shaped such that the orientation of the plug for the headshell pre-determines the offset angle. If that angle is not the above recommended 20.5 degrees, how do the other recommended parameters work? I am guessing that the built-in angle is 20.5 for the 64S, and there is no problem, but it would be good if you can confirm that. Anyway, I've got a UNI with the 64S template. |
05-19-13: Lewm
Dear Henry, I am a bit puzzled about a recommendation for a specific headshell offset angle to go along with the recommended P2S distance and overhang for the 64S. In the case of headshell offset angle, isn't one "stuck" with the built-in angle? Option 1 - Buy a headshell with slots Option 2 - Drill the headshell holes oversize Option 3 - Drill the cartridge holes oversize Option 4 - No bolts, superglue the cartridge to the headhsell Option 4 is the best sounding, but you need to keep the glue ultra thin for maximum energy transfer. |
Dear Henry, I've got my answer. No worries. |
Dear Thuchan, I will post to you the email address of my
uncle Boris.I am sure he will gladly exchange his Natalija
for your speakers provided he can use his 'Medvedev'
capacitors with your HF drivers. He will namely not part
from his Russian oil capacitors.
Regards, |
Halcro, thanks again for your information. I will wait for SMARTracker to arrive before experimenting. I assume that once setting P2S to 231.5 and using UNIdin and align it to null point properly, offset angle and overhang would be adjusted to the new spec automatically, if I am reading your post correctly.
This is a lot of fun and please hijack the thread as you wish. FR66s, FR64s, I needs all the help I can get for both!
I also recently got the B-60 VTA adjustment replica for FR66s which is great. Now I will have to save up for another one for FR64s. However, I will need to find a new armboard as my Micro Seiki armboard for FR will not accomodate the larger diameter VTA on the fly module. |
Thank you Nandric, I am very eager to get in contact with your uncle Boris. We may put his Nataljia into the speakers and tell him everything is fine. The speakers are big enough. Do you think it might become a bit risky for me...? |
Dear Dover, I am well aware that one can "twist" the cartridge in the headshell to obtain a non-standard offset angle. I suppose I should have acknowledged that possibility in my post to Henry. In fact, that's what one has to do, in order to use Daniel's recommended FR64S geometry. Twisting the cartridge in the headshell did not work well with my Dynavector, which experience I described elsewhere, maybe not on this thread. Thus I am biased against thinking of doing it. But I also think that the issues that arose with the Dynavector (nasty distortion) had to do with the unique design of the Dynavector, where the vertical pivot is distinct from the horizontal one and very close to the cantilever. Ergo, I am open-minded about twisting the cartridge in the FR64S headshell. More anon. |
I was as puzzled as Lewm with the offset angle .etc., and reread the article by Kessler and Pisha about the Tonearm Geomtery and Setup. I see that Lewm 'got the picture' in
his next post ( 05-19-13) but he is better than I in, inter alia, math and physics. The confusing part is the P2S distance. One should forget about this parameter and
consider that overhang and offset angle are also involved in tonearm geometry. According to Kessler and Pisha the most Japanese tonearms got the overhang wrong. That is to say not optimal in correaltion to the eff. lenght.
I got the answers from Daniel about his reasons to change his opinion about the 'usual' geometry but I need his permission to quote from his email first.
Now my own position is this. While I like to consider myself as 'pedantic' I am, lucky me, not an perfectionist. I made so much effort to get this damn distance for my FR-64 exactly at 231.5 mm and even more effort to adjust 7 headshells with carts on the 'line curve' of my Mint protractor that I have no intention whatever to mess with offset angle and overhang at all. O. Wilde wrote:'I have simple testes, I am always satisfy with the best'. My philosphy is: I am satisfy with the second best.
Regards,
|
I am privately wondering how one can cite the true pivot of the FR tonearms to an accuracy of 0.5mm, since the top of the bearing housing is a flat circular plane, IIRC. (The FR64S is not in front of me as I write this.) So, you need a REALLY good eye to find its exact center. And in fact, one has no way to be absolutely certain that the center of the circle is exactly above the center of the pivot point. Well, I will make myself satisfied by believing that it is, in any case.
Nikola, Here is a philosophical question: if you know something is second best, then you must have identified a "best" with which to compare it. Having done so, how do you know that your own best is truly best? Which means that second best might in fact be third best, or fourth, etc. Subjectivism rules. |
Dear Lewm: Agree with you and I could add that first than all how can we could be absolutely sure that the hole ( arm board ) where any tonearm is mounted had the accuracy need it because we are measuring the distance: Pivot to spindle and that pivot position is critical?.
Regards and enjoy the music,
R.
Regards and enjoy the music,
R. |
Dear Lew, Your philosophical questions are to difficult for me. Anyway the questions like: 'how do you know?' Should I say :'I have read this in some Magazine' to impress you?
But If you owned the Mint tractor specialy made for your FR-64 S in conjunction with the exact dimension of the spindle of the TT involved you would know when this exact
distance of 231,5 mm is 'there'. Namely when the stylus follows exactly the thin line curve 'cut' with the laser.
Regars, |
Dear Thuchan, It is risky to tease someone because of his
family. This is 'not done' because nobody can choose his
family. I wish I could so we could be the real twin brothers (grin).
Regards, |
Dear Nicola,
I have no wish to offend a man with "simple testes".......but by having a Mint tractor specially made for your FR-64s at 231.5mm P2S distance.......you are merely having a Baerwald geometry transcribed for the new distance.
You are not having the Dertonarm geometry with its 14.5mm Overhang and 20.5 Offset angle because Yip makes his Mint Tractor to Baerwald unless specifically ordered NOT to?
I thought you had Dertonarm's UNItractor with his Template for the FR-64s at 231.5mm?
If so........all you need to do is align to this to achieve the correct Overhang and Off-Set angle for the new geometry.
And after listening to the difference for a few days........your testes may become more cultured?
Regards |
Dear Henry, I explained my situation and prefrence already. I also mentioned my Mint tractor explicite so if I owned UNItractor I would certainly mentioned this. You stated in an earlier post to have problems with my 'deductive capabilities'. To demonstrate otherwise I only need to ask you to look at your first sentence in your post and correlate this one with your last sentence. While you was reluctant to 'offend' me with my 'simple testes' in the first sentence in your last sentence you want me to become 'more cultured'. Very strange logic I would think. Besides deed you not put your beloved question marks by the 14,5 mm overhang and 20,5 offset asking if this make any difference ?
Regards,
|
Dear Henry, I am sorry to have missed the Aussie humour.
I thought that we were talking about the tonearm geometry
while you was , as a good friend should do, worried about
my physical 'state'. Years ago I made similar lapsus by my
other Slavic brother Lewm with the compliment that he was
a smart gay according to me. To paraphrase Shakespeare:
'what is in one letter?'
Regards, |
Dear vinyl-o-philes, it is perhaps a bit late to chime in but I haven't noticed this thread until now.
For the FR 66S enthousiasts: I don't want to be the fly in the ointment, but some experts (like Jonathan Carr of Lyra) say that the FR-66S rings as hell.
What is your response to this statement?
I also have a technical question for you. I own a FR-66S myself, which I'm using with a SPU Anniversary 85. The length of the SPU is 52 mm instead of the 50 mm recommended by Ikeda.
So the effective length of the tonearm is 2 mm above the specified length and the overhang is more than 12 mm as specified.
What should I do to get the right geometry: leave it this way or adjust the S2P distance to 297 mm (295 mm is specified)?
Chris |
So Chris, As an owner of the FR66S, what do YOU think of JCarr's opinion? There is another guy who posts regularly on the Analog blog who also does not like the FR66S for the same reason. |
Dazzdax,
Have you checked the alignment with a good Protractor or Universal Template like the Feikert?
If it is easy for you to adjust the Pivot to Spindle distance of the tonearm....just do it so it aligns with the your preferred geometry (Baerwald, Lofgren, Stevenson).
Dertonarm has his own geometry which works very well for his UNIprotractor.
Just ensure that the off-set angle is OK at the Null Points and you should be fine. |
Hi Lew, I believe Jonathan Carr has a point here. Sometimes I do hear something that you can call ringing when comparing vinyl playback with digital.
Of course it is not a proof this is due to the tonearm only because many other things can also contribute to this phenomenon.
Moreover, I find the bass reproduction is not state of the art: it is rather pompous and lacks definition and slam.
Chris |
Hi Henry, I use the protractor which is supplied by the manufacturer of my turntable, Acoustic Solid. It is a Feikert like protractor.
Using the DB Technologies for the off set angle check at the null points.
Chris |
Chris,
The issue about P2S and overhang using SPUs is something I've also struggled with using my SME M2-12R. Especially aggravating is the small de facto variance among SPUs that purport to have the same overhang. I read surprisingly little conversation about this issue, which will wreak havoc if one's armboard and tonearm-mount are unmovable.
I do what Henry recommends, which is to adjust P2S so that the SPU aligns with my selected geometry. Fortunately, the SME has a sliding mount; otherwise I'd be out of luck. I use arc protractors from MintLP and Accutrak, and I'm able get the stylus to track the arc almost perfectly. The UNI-Pro, which I also have, doesn't really work in this instance because it is contingent on a prescribed P2S.
Bill |
Hi Bill, thank you for your recommendation. So if I'm correct the specified P2S distance is not a "holy grail" that cannot be touched by mere mortals?
More important is the correct geometry at the null points (that is that the cartridge is parallel to the grid on the protractor)?
Chris |
Hi Bill, thank you for your recommendation. It appears to me that the manufacturer specified S2P distance is not some kind of "holy grail" that cannot be touched by mere mortals.
According to an geometriy calculator as supplied by Vinyl Engine you can calculate the distortion if the geometry is changed.
If I change the S2P distance to 297 mm (instead of 295 mm) and the overhang can be kept at 12 mm, I would end up with reasonable distortion. But you will deal with other null points!
Chris |
Wrm57
If you use an integrated headshell cartridge like the SPU then you can't adjust the offset angle.
The SME arm you have is designed for LofgrenA (Baerwald). It is also designed such that that alignment can be set by adjusting the base for whatever cartridge is mounted.
In other words the P2S distance is variable, the effective length is variable and the offset angle is fixed. If you used a headshell and separate cartridge with sufficient clearance in the holes or slots, then the cartridge can be twisted to allow other alignments to be achieved (although Lofgren B doesn't require a twist, merely an adjustment of the sliding base.)
You can use any standard two point protractor to set up, or a the Dennison which works for any unknown mounting distance. (The Uni protractor uses the same principle, and doesn't require you to know or set the P2S, but it has to be Lofgren A/Baerwald.)
Unless you know the exact actual effective length, an arc protractor is not going to help, and if you did know it, it would only apply with LofgrenA/Baerwald.
If you have the wrong E.L, then the offset angle will be wrong for whatever P2S distance that enables the arc to be tracked.
John |
I think Bill's method is the only rational one for use with fixed headshell cartridges like the SPUs and FR-7 types.
Yes.....the off-set angles may be slightly different to the prescribed ones at the null points......but only by 1 or 2 degrees in most cases?
If you can align your styli to all be 'visually' within these limits......I'd suggest you're doing alright?
That's why I recommended to Chris to check the geometry of the stylus at the null points after adjusting the arm to follow a preferred arc geometry as Bill does.
John appears to be offering no solution at all......and if he thinks the UNI-protractor uses Baerwald alignment.....I believe he is mistaken?
Dertonarm has developed his own alignment called UNI-Din which places the null points differently to the others.
He also recommends moving the FR-64s tonearm to a S to P distance of 231.5mm rather than the recommended 230mm.
As he is a rather renowned fan of the FR-7 series of cartridges.......I can't imagine him sabotaging these cartridges with damagingly incorrect off-set angles? |
Chris,
If you change the mounting distance to 297mm it will be fine if this gives a 12mm overhang. If you are using an SPU the headshell offset is fixed, so the only variable is P2S.
If the arm was designed for a 50mm as opposed to 52mm pickup, then the real effective offset will be slightly less as the effective length increases, but the basic arm geometry remains the same, it just needs more P2S distance. You can use the original protractor to check, as the nulls will be the same.
John |
Hi John,
Yes, I've come to accept that the offset angle will be a little off using my arc protractors, both of which are designed for Baerwald, with the SME and SPUs. I just don't see any way around it. It seems to me that SPUs are inherently compromised in this regard--and inconsistent. For example, if I set the P2S to enable my Royal GMII to trace the Baewald arc and then swap on my Mono GMII, the Mono is slightly off, which I read as overhang inconsistency.
With the UNI-Pro, if I set the tonearm to SME's prescribed P2S and check alignment with the Baerwald template, which Daniel says is the one to use with the SME, it's way off, as one might expect. So, I can slide the SME along its base, changing P2S until the stylus drops in the template's hole. But then offset angle is wrong because the orientation of the template itself is no longer proper, seeing as how has been situated in relation to the prescribed P2S. And because the UNI-Pro is orienting the stylus using a single point rather than the multiple points available using the arc protractors, I trust it less--unless its controlling parameters like P2S remain fixed.
I suppose I could reorient the template and further change P2S until the stylus drops in the hole and the cantilever looks aligned (which I would take to mean offset angle is correct). However, I assume that the setting on the Uni-Pro's micrometer has been determined according to the manufacturer-specified P2S. Is this not so? Then changing the P2S scrambles this variable, too, doesn't it? With these two primary coordinates thrown to the wind, this alignment procedure seems rather random and chaotic.
But I'm certainly no expert in these matters, just a guy wrestling with SPUs and alignment tools in hopes of good sound, so please correct me if I'm not seeing things correctly.
Hi Chris,
Yes, that's what I've come to accept by shifting the P2S: slightly different null points and slightly incorrect offset angle in exchange for minimal overall distortion. I just don't see another way with SPUs.
Bill |
Bill, With the UNI-Pro, if I set the tonearm to SME's prescribed P2S and check alignment with the Baerwald template, which Daniel says is the one to use with the SME, it's way off, as one might expect. So, I can slide the SME along its base, changing P2S until the stylus drops in the template's hole. But then offset angle is wrong because the orientation of the template itself is no longer proper, seeing as how has been situated in relation to the prescribed P2S. The Uni Protractor functions in the same way as the Dennesen - the principle does not require the actual dimension in millimeters of P2S distance to be known. It is irrelevant to the principle, and for some arms with sliding or movable bases like the SME, saying that it is necessary to measure P2S is just plain wrong. It is not my opinion, just a fact. The micrometer function adjusts for the different alignment options and, if it is set for LofgrenA/Baerwald IEC, then, just like the Dennesen, when the movable arm is correctly positioned over the tonearm pivot point, the null is correctly orientated, and the cartridge should line up with the grid lines. SME give an effective length dimension, but it is nominal, based on a notional standard cartridge mounting hole to stylus dimension. And the related P2S refers to this. The SME sliding base accommodates variations in cartridge dimensions (which alter the effective length and cartridge offset), thus allowing your SPU to be set up correctly even though is has no adjustment. However, I assume that the setting on the Uni-Pro's micrometer has been determined according to the manufacturer-specified P2S. The micrometer setting relates only to the particular alignment (LofgrenA, B Stevenson) which is initially derived from the inner and outer recorded radii (IEC, DIN etc), which gives rise to fixed numbers for the linear offset and the nulls, which in the case of your arm (and any other using that alignment of whatever effective length), LofgrenA/Baerwald IEC. It is easy to get lost in all this stuff. And I know there are many people confused by it, which is why I try to comment when I see misunderstandings. Regarding the SPUs, the fact of differing compliances might cause slight variations as VTF and VTA change when changing from one to another. How much of a variation is there in effective length? John |
John
Thanks for the explanation. I stand corrected on the relation between P2S and alignment using the UNI-Pro, and on how the micrometer settings are determined. I had concluded (erroneously, it turns out) that they were related because the UNI-Pro requires centering over the pivot, which, in turn, has typically been located according to the manufacturer's prescribed P2S. I use the UNI-P2S, which is extremely handy.
As I recall, the variation between the SPU Royal GMII and Mono GMII is tiny--easily less than 1 mm off the arc. But that's too much.
I hadn't thought of it as a VTF and compliance issue. Could be. The differences between the two SPUs are a non-negligible half a gram in tracking weight (3g for the Royal v. 3.5g for the Mono) and 4 µm/mN in compliance (8 v. 12). I imagine that the extra weight and higher compliance of the Mono could cause it to splay, pushing the stylus beyond the arc, which is the direction of the error. That's a very good point.
Still, I've felt more comfortable--and gotten better sonic results--using the arc protractors on this arm with SPUs. After this discussion, though, I'll experiment further with the UNI-Pro.
Apologies to the OP if I've pulled the thread off topic.
Bill |
John, Is it not the case that for your statement that the P2S is irrelevant for the Dennesen or the UNI to be true, the cartridge must be aligned (ideally) perfectly with the long axis of the headshell. If the cartridge is "twisted" inward or outward with respect to the headshell, then the P2S dictated by the alignment grid on the template surface would put the pivot at some position different from ideal. I guess this would still "work", in the gross sense of the word, but if you want highest precision for a particular specific classic geometry, what I say must be true. Yes?
Of course, for an SPU cartridge, the point I raise is moot. |
Halcro, Yes you are correct: the only way to adjust cartridges like the SPU on arms like the FR64 and 66 is at the base, as the headshell offset is fixed. Which is why on a specific arm you have to use the existing specific arm alignment which uses that headshell offset. In other words, the given nulls. Only by doing this will the cartridge line up correctly. John appears to be offering no solution at all......and if he thinks the UNI-protractor uses Baerwald alignment.....I believe he is mistaken? The solution I gave for SPUs is straightforward: adjust the base to fit the original nulls. Don't use an arc. If you have two SPUs or FR7s or whatever, and they don't have the same dimensions, then the base has to move or you accept a compromise. For removable headshells with slots, you can use whatever alignment you like, but as I have told you in a past post, if you want to swap with an SPU you have to set it up first, and only then use a slotted headshell to mount and adjust another cartridge, without moving the P2S. and if he thinks the UNI-protractor uses Baerwald alignment.....I believe he is mistaken?
Dertonarm has developed his own alignment called UNI-Din which places the null points differently to the others. You are right to question your belief ;-) As it is the Uni (for universal) protractor, DT has incorporated an adjustment to allow different alignments, one of which is LofgrenA/Baerwald IEC, and another is his version of LofgrenA which is derived from inner and outer recorded radii parameters which differ from IEC and DIN, thus giving different nulls. In the case of the SPU, unless the arm has an offset which corresponds to that alignment, then the alignment can never be achieved, and the cartridge will only ever align at one null. That is the way it is. All else is compromise. Whether the compromise is to accept a misalignment of a couple of degrees is up to you. In the case of the FR66 the original P2S and overhang seem fine to me. A change to 296 makes little difference. Nulls around 63 and 115 would work ok. The thing is to get the offset as accurate as possible, as this is the parameter most prone to error. John |
