Tonearm recommendation
The arm and cart work as a team and for the Rosewood and 103r you probably can't better the FR66s. If you want a mono cart, I suspect the same goes for the Miyajima Zero. With a removable headshell it would be relatively easy to switch carts. I was under the impression the Blackbird could accommodate 2 arms. I don't know what's involved, but that might be an option to add a lighter arm? |
Raul, "Dear fleib: why is the best team those cartridges with that 66?, maybe I'm missing something and always is time to learn so some " light " from you can help all of us." Sorry, I didn't see your post. Those carts are very low compliance. A low compliance cart needs high effective mass arm to control the cart and be a stable platform. Put a stiff, heavy tracking cart on a low mass arm and the resonant frequency approaches or goes into the audio band. The amplitude of the resonance can be quite high, producing colorations. On another forum someone mentioned that a "guru" advocated a resonant frequency of 18Hz for a particular cart. I can only assume this was to augment the deep bass on his records or system. We often deal with the opposite situation - a cart with compliance too high for a particular arm. In that case the resonant frequency goes low - easier to live with if SQ doesn't suffer from poor low frequency tracking and/or sluggish sound. Peter Pritchard (designer of 50cu carts), advocated a resonant frequency of 6.5Hz. This is above the warp region yet the arm will have enough mass to be stable. Arm damping (fluid) acts to limit the amplitude of the resonance peak and spread it across a wider frequency band, mitigating the affects. Regards, |
Raul, > "Mantain frequency resonance value, between tonearm/cartridge, in the range of 8- hz to 10 hz is something that many of us always are looking and is something all of us want it." The recommended range is 8 to 12 or 13Hz. > "Now, what happen during playing because the theory is on static way where the cartridge is not ridding the LP grooves." No, it's not about static. There is no resonance with static as the name implies. We're talking about dynamic compliance, arm mass, and resultant resonance or affect on performance. > "The theory of that cartridge/resonance frequency is that to low frequency like 4-6 hz cabn be exited and coincide with vibrations/resonances generated by the TT/cartridge and then can make that in some areas of the LP surface the cartridge/tonearm " jump "/mistracking." No one is talking about that. This situation is the opposite - a low compliance cart. No theory was proposed, especially about high compliance carts on a heavy arm. Arm/cart resonance is a measurable phenomena. It occurs. If it occurs close to, or in the audio band it will cause intermodulation. > "As I said the all metal FRs are because of that metal a natural/self resonace/vibrations generator device but along that is a NON DAMPED DESIGN!!!! go figure." Miss science class when you were a kid? Self resonance vibration generator? Would that be static or dynamic self resonance? That's a cute anecdote about the MC2000, Unfortunately, it has nothing to do with the situation at hand. Regards, |
Raul, You're looking for subjective proof? How bizarre. Crazy Bill has 2 low compliance carts and you start talking about one that resonates at a very low frequency, a high compliance cart on a heavy arm. This is supposed to refute some unstated theory. Apparently you don't know what you're talking about. You're the one who brought up recommended frequency range, so you can refute it as a theory? FACT - When a low compliance cart is mated with a light arm the resonant frequency goes up. If that resonance approaches or goes into the audio band it will produce intermodulation distortion. OPINION - The Rosewood and FR66s sound excellent together. Crazy Bill said it sounds better than his 12" Jelco, a fluid damped arm. IMO this is a great combination. I haven't heard the Rosewood sound better, maybe you have, but your lack of knowledge and vested interest makes you suspect. Are you selling arms now Raul? If so, I hope your partner knows more about this stuff than you. Sincerely, |
Raul, I think your patronizing attitude about others' knowledge on this and other subjects, is not appreciated, at least not by me. Mine is not a general recommendation. It is specific to Crazy Bill's two low compliance carts, and possibly a third, the Miyajima Zero. I admit the Zero recommendation is guesswork on my part. I think I stated as much on my initial post. I don't think the FR64s and 66s are a good choice for general use and cartridge swapping as some other people might, but in this case, mated w/Rosewood or a modified 103, it can sound quite good. In certain circumstances the arm is prone to ringing, but this is not one of those circumstances IMO. Ringing can be alleviated by damping the arm tube. Having a replaceable headshell allows finding a synergistic combination and adjusting mass somewhat. It was you who challenged my recommendation and started talking about ideal resonance range theory, yet you made no recommendation. Waiting for your arm to be introduced, or is that not imminent? This forum happens to be in English. If you can't understand what's being said or can't express yourself so you can be understood, whose fault is it? You're obviously remedial in some of these tech subjects, but I don't think challenging others is a good strategy to learn. Sincerely, |
Hi Nandric, In a literal sense the arm does not follow the groove, or only as much as the cartridge body. I agree, it's the stylus that tracks/traces, the groove. Considering different aspects of record player functions, it's usually simpler to reduce to two dimensions like horizontal and vertical, but tracking is in four dimensions in-groove (don't forget time). Rather than add dimensions with other functions, in reality the other functions also operate within those four dimensions. If you consider the movements of the stylus as being within an imaginary sphere of tracking, the movement of the arm across the record can be seen as a separate function operating in the same dimensions of time/space. The same would go for vertical movement - tracking a warp. Neither of those functions is completely horizontal or vertical. A record player is a bizarre device. Maybe that's part of why we love them. "They" used to say it's like a bumble bee, by the laws of aerodynamics it should not fly. It turns out they greatly underestimated the speed of the bee's wings flapping. Regards, |
Raul, You're trying to win an argument instead of making a recommendation or two. That was the request of OP. It's all right to support what you say with technical information, but if the only way you can do that is by insulting others, you're not going to win the argument you started. You seem to assume you're the only one who can hear (discern audio differences). You assume too much. If I may suggest, discuss something like the amplitude of resonance and ways it can intermodulate and affect the sound, and refrain from saying you can hear it and someone else can't. That last part is implied and saying it will only alienate others. You seem all wound up and out to prove something. Why don't you give that TEA BS a rest, and lighten up? Regards, |
Dover, Sorry I didn't see this sooner. You accept this nonsense as correct, or just the part about a noisy mechanism? >>additional we have to remember that the 64/66 are dynamic balanced designs and all dynamic balanced designs always generate ringing ( noise/distortions. ) through the dynamic mechanism but two tonearm design: the MAX 237/282 and Luste GST-801. Adding to that problem the micro and macro waves in the LP recorded surface makes that in a dynamic balanced tonearm design the " normal " continuous changes in VTA/SRA/VTF that always exist in any tonearm ( static balanced included. ) been more pronounced do that when there is a crest in the LP surface the deflection in the cartridge cantilever is higher in a dynamic balanced design that in the static balanced one that works with natural gravity where in the dynamic the mechanis always force to mantain the VTF but when is against a crest the cantilever is pushed up making a higher cantilever deflection. These are the ravings of someone who makes things up, or doesn't understand what he reads. When a static balanced cart is riding up a warp VTF is substantially reduced. The cart/arm is accelerating upwards. What happens when VTF is reduced? VTA is steeper angle. At the crest VTF/VTA are more affected with a static balanced cart and it's much more likely to mistrack. Due to the constant spring action a dynamically balanced cart will maintain a more even VTF. Back in the '80s we were setting up dynamically balanced arms by splitting the force. Regards, |
Raul, you're quite long winded and you bring a novel aspect to technical matters. Thought you might like to know, on another forum you're referred to as the 32 bit Bandito. Due to the length and number of your posts, I think Kraken might be more appropriate. To address your last post, did J. Carr say that all metal arms must be damped? I doubt it, but it doesn't matter. You use that as justification for: *IMHO no one can " to suck life out of the sound or smear it "" by damping a tonearm. You can't overdamp a tonearm.* With all your ear training I'm surprised you can't hear the affect of over-damping a tonearm. One can MEASURE a negative affect on transient response by over-damping. It also tends to kill the natural sustain of acoustic instruments. I agree with Dover, arms are easily over-damped. If it was Dgarretson who said that about vacuum hold down, I tend to agree with him. It's easy to suck the life out of the music by over-damping. I think you might be surprised by the number of people who add fluid damping to their arms. KAB sells a trough and paddle device that is popular, and it's very easy to DIY. Too many words Mr. Kraken, too many words. Sincerely, |
Raul, I didn't call you stupid. It was long winded, which I think is accurate. If you object to your nicknames I won't use them. It might interest you to know that the lower the compliance of a suspension, the lower the amplitude of arm/cart resonance. We happen to be talking about 2 very low compliance stereo carts. You previously talked about the metal arm generating resonance and distortion. That's impossible. The arm is not a generator. I assume you meant propagating or amplifying. There are many mistakes like that in your posts. I don't have the time or inclination to correct them. You've been posting on this forum in English for many years. I've long thought you use language to disguise lack of specific knowledge. If you look over this thread I think you'll see that you are the predominant responder. You say the same thing over and over. We heard you the first time. Why don't you give us a break? Sincerely, |
Raul, *I said " over and over " because almost no one post the right answer explain it why I’m totally wrong or why they are recomended " this or that ". * Because it doesn't work like that. You made a case for damping. Damping is one factor, not the main consideration. In the initial post we read that the Jelco arm is inferior. I think you would agree, yet the Jelco is fluid damped at the pivot. Clearly, there are other factors. You talk about ringing and amplifying vibrations. In my experience with these FR arms, the right headshell combined with a suitable low compliance cartridge, negates this consideration. I've heard them with a small amount of armtube damping and less than perfect match with cart compliance and still nice results. Maybe the 4 point would be better, I don't know, but I don't think it falls within the price constraints. This is a matter of opinion not a case of right/wrong. Sincerely, |
Raul, Did something upsetting happen in your life? To be honest, your posts seem irrational. Sometimes when life throws us a curve we react in strange ways. To avoid a negative situation it would be natural to go to something that gives us pleasure, like audio. I'm not being condescending, your bit about pure musical information going through the wires is bizarre. Of course you can overdamp an arm. Look at the output on a scope. In the past you've made some great contributions to our hobby. If something else is bothering you now, it might be better worked out with a friend or family. Regards, |
Raul, Still doesn't make sense: **What I’m talking is what in a non-existen " perfect audio world " we have in those internal wires: ideally a pure non-contaminated signal information. Overdamping is not going to cure the ills from the source. In fact, overdamping will take you further away from your "ideal signal". Specifically, overdamping a tone arm will negatively effect cartridge transient response - rise/slew. I think you call me dogmatic because I won't agree with the nonsense you post. All the BS about your ear training and you seem incapable of correlating what you hear, with what's going on with the record player. |
Dover, *I have also made a metal jig to ensure that the FR64S's that I use are installed with a 231.5mm pivot to spindle distance. It is accurate to 0.1mm and this pivot to stylus distance recommended by Dertonam makes for a considerable audible improvement over the factory recommended 230mm.* Any further explanation? Factory alignment nulls are 59.2 and 120.4mm? Somewhat unusual, inner null is close to Stevenson and outer is close to Baerwald. What alignment do you use? Regards, |
Lewm, Dover, I assume this is the UNI-DIN alignment I read about (Fremer?). Nulls at 66.3 and 112.5mm. If you hunt down the article you'll see the curves for alignment error. It looks pretty good. I'm reluctant to call alignment error, distortion. Unless/until someone correlates alignment error with a master type source and a distortion analyzer, I think the use of the term distortion is misleading. Some people throw this word around who clearly don't know what they're talking about. I don't have an FR arm and I haven't read the past threads. It's a little hard to imagine how or why increasing mounting distance 1.5mm would make a significant difference. The only thing I could come up with is a miniscule reduction in offset angle. I believe perception of differences is sometimes fueled by anticipation and expectations, although I'm not saying that is the case here. It could be that Jupiter aligned with Mars and Dertonearm is the 7th son of a 7th son born on a blood moon (whatever that is). Don't take offense here, I'm a sarcastic type. It's interesting to note, the factory nulls minimize inner groove problems with that null being close to the run out groove. The outer null is close to Baerwald. UNI-DIN moves the inner null out near Baerwald, and 112.5 puts the outer null in closer than Loefgren(B). I think this minimizes error in the center of the grooves where error is highest. Dover, VE has a free protractor called Chpratz. It's just a calibrated straight line. With it, you could experiment with different alignments, although it's not easy to set up like a Dennesen. Regards, |
Sorry Raul, You can't lump all types of vibrations into a pile and deal with them by damping. It doesn't work that way. Damping doe not kill vibrations, it mitigates the affects. In this case fluid damping an arm pivot can reduce the amplitude of resonance by approx. 50% depending on compliance, mass etc. Damping does not stop the resonance, it redistributes it over a wider frequency range with a less severe peak. Overdamp the pivot, and as the name implies it's too much, it impedes motion. That's why Stingreen and Crazy Bill experienced negative affects with overdamping. There are other ways to deal with vibration depending on type and situation. The use of mass is a way to convert vibrations to heat. Consider Mosin's Saskia table. It has a 200 lb. plinth made of slate. Even though slate is good at transmitting vibrations the mass converts them to heat. Another way is to dissipate vibrations and convert to heat or direct them out of the table. Some coupling should be rigid, not damped. Overdamp everything on a table and the sound turns to mush (opposite of live music). Regards, |
The simple definition of damping is to reduce oscillation. If we use a broader definition as in physics, it would be to reduce or dissipate vibration. I was making a distinction between different types of vibration control, but it does not matter. Critical damping is just enough to prevent vibration or enough to allow something to return to its rest position. Overdamping is a state where vibration is prevented to the extent that a moving part is prevented from movement. A fluid damped tonearm does not have to have the fluid located at the pivot, for the pivot to be damped. Attach a paddle to the base of an armtube and have it dipped in a fluid trough when tracking a record, and you're damping the pivot. Overdamp the pivot and you're restricting arm movement. |
Atmasphere, **I suspected that was the case and so made sure that I clarified my position, which is that there are two forms of damping- one of which cannot be overdone as I had previously stated, and the other (which I never use) which most definitely can!** You never used the fluid damping trough on the Triplanar? There are many kinds of damping schemes and it can certainly be overdone and/or misapplied. Try some rubber washers between cart and headshell and hear how it sounds. |
The unipivot has some advantages which are undeniable. Those advantages are reflected in the number of top performing unipivot designs. One advantage is damping, a feature so highly touted in this thread. When SME came out with the model V, many design features were to control resonance. That included the tapered armtube and the fixed headshell. High end "contenders" in the '80s were Zeta and Alphason 100S - fixed headshells. The advantage of a fixed headshell is to eliminate the physical boundary and its tendency to reflect vibrations back to the cartridge. This might not be an insurmountable advantage, but an advantage nonetheless. By its nature, a fluid damped unipivot can easily be critically damped. The potential to over or under damp a unipivot should not be considered a fault. Any arm can be set up improperly. Most of the mechanical energy from the cartridge does not get converted to electricity. That's why top cart designs today use exotic materials and design features to dissipate energy. An elegant solution for excess mechanical vibrations from the cartridge is to dissipate down the armtube and convert to heat by the mass of the arm or plinth, or run it out of a foot. The contention is, this is more easily accomplished by a unipivot; one clear path for vibrations to exit, while conventional bearings are a two way street. The task of a tonearm seems impossible and contradictory, to be a stable platform while completely free to move laterally and vertically. Two dimensions of movement is an oversimplification. If an arm is moving laterally and vertically at the same time, the movement is angular or three dimensional. Are conventionally pivoted arms necessarily more detailed and exact? I think performance defies that generalization. Our Mexican friend likes to use the word distortion. This is meaningless without supporting evidence. The Dynavector 507 II is a bi-axis design with intentionally high inertia laterally, and low vertically. This type of inertia scheme is used by the DP8, apparently to good effect. I'm not writing this in support of arms I haven't heard, but an arm designer shouldn't be expected to answer ignorant, unintelligible assertions. Regards, |
Raul, **Unipivots works during playing in continuous desequilibrium, its bearing damping is not to really damp the whole tonearm but, mainly, trying to put at minimum that unstability during playing and that’s all.** A unipivot maintains stability by the distribution of mass and the center of gravity in relation to the pivot. It's like a platter on the bearing. A well designed table will have the mass of the platter distributed so it does not have a tendency to wobble. If the center of gravity is too low or high, it will be unstable. Some unipivots use no fluid. How would they work if they relied on fluid? A unipivot feels unstable with manual cueing because there's no weight on the stylus. The system isn't loaded. As soon as you let it go, the cart straightens. If the bearing was in a constant state of disequilibrium (good one), you would not be able to listen to it. A fluid damped unipivot is damped, any way you cut it. There might be suggestions for the amount and viscosity of the fluid. Neither the DP8 or 507 II are unipivots. They both use high mass (inertia) in the horizontal plane to optimize tracking and bass response. The difference between bearing friction and high inertia is in the type of resistance to movement. Effective mass and inertia are the same. The 507 is designed to have high inertia (mass) laterally. You call it friction, but it's part of the design. Less than 50mg lateral sensitivity and less than 40mg vertically - also part of the design. The little vertical arm is so light, that pivot is damped to keep it from flying away. With all the damping going on, I would think you would be enthusiastic. You're innocent until proven guilty? You keep saying the same thing over and over as if that makes you right. As soon as the thread gets interesting you start up again. You're the only one trying to prove something. Lighten up, life's too short. Regards, |
Raul, Nice story, but it's a little hard to believe. You and your scientist friend are in a lab playing records and watching the stylus with an electron microscope? This was at normal speed and slow motion. You can't see a record groove with an electron microscope unless it's painted with conductive coating. Vinyl is an insulator. Must have been a pretty big scope to fit the record player. Check this out: www.youtube.com/watch?v=GuCdsyCWmt8 Even if your story is true, it's an anecdote about one particular unnamed pair of tonearms. You think there are better arms than the 507 II. Okay we get it, but not everyone agrees with you. I read 2 reviews of the arm and the reviewers bought it from Dynavector. Probably a decent arm? What don't you understand about bearing friction and inertia? Regards, |
ct0517, **The Air Bearing affords isolation, and allows me to run a straight shot of unshielded wiring. The person that makes the loom - Take Five Audio, tells me NO pivot arm customers can use this loom for two reasons. This doesn't make sense. Why would someone with a pivoting arm want to use a loom designed for an air bearing linear? Are you saying a pivoting arm can't use a straight run of wire? Of course you're not, you just want to get in a shot about antiskating. Hum issues with the arm being bolted to the plinth? Most arms are bolted to an armboard, but what's it made of etc. ?? I understand you like the ET, I've heard it sound excellent, but why the inappropriate comments from the guy who makes a wiring loom? Regards, |
Raul, **My first advise to any audiophile ( other that attend to listen live music. ) is to listen as many audio system you can listening ( if you can, sometimes we can't do it. ) to the same LP tracks that you know better that your " hands ".** Still don't get it? We don't want your advice, at least I don't and I think the majority of posters here. You think you're the only one who listens to live music? You think you're alone in training your hearing? You do get the award for checking out the most equipment and knowing the least about it. Regards, |
Don_c55, I tend to agree with your list of necessary features and I realize you said SOTA. I believe the OP referred to arms in the $6K and less range, and while all these features could possibly be incorporated in a $6K arm, sometimes the elimination of a feature is an engineering decision. For me, VTA OTF is a necessary feature and I would give up calibrated azimuth adjustment to have it. Azimuth is set-and-forget adjustment, and while a calibrated azimuth might be convenient for cart swapping, I think it's more likely to compromise performance. Even though this thread includes a lengthy travel log and fanciful stories, I enjoy reading personal opinions and comparisons and wish there to be more of that. I think these opinions are equally valid as a prof. review, maybe more so. In the spirit of time spent, already compromised, I ask everyone (not you Don), can't we move on? Regards, |
and we plod on..... Most manufactures do provide a protractor. Best reg. protractors are provided by arm manufacturers. What do you want, a Feikert? Add that to the cost of your arm and complain about that. Ct0517, I found other mfg. comments (Re. 507) you posted, interesting. Thanks. Lewm answered the bit about being able to use a straight run of wire in a pivoting arm. The rest of the quote from the loom maker is bizarre. It's the arm with exposed unshielded wire which is susceptible to RF and a Faraday cage won't help as long as the wires are exposed. ViV Rigid Float anyone? Interesting concept there, trading off alignment error for zero offset. This isn't a new concept. Yamaha had a YSA-2 upgrade for the GT2000, and the RS Labs which also had vertical cantilever offset compensation. |
Ct0517, James Bond Maneuvers? Is there a song to go with that? Is the ET grounded? Q ) In this application what's the difference between a Faraday cage and a 100% shielded cable? A ) A Faraday cage is grounded. I don't think you're suggesting a pivoting arm can not have portions of the wire exposed, but I'm not sure what you're suggesting. Regards, |
Ct0517, About the James Bond Maneuvers theme song, is it Kenny Rogers "The Gambler"? I have 6 tables and 7 arms in various states of modification and functionality. All the arms are conventionally wired and the cables are shielded, so there's nothing to see. When I rewired my Sonus Formula 4 I made the same choice as Griffithds. It has a 5 pin DIN on the bottom of the pillar. I don't use the original cable. Nice exit, BTW. Regards, |
Griff, Glad it's working out. Any thoughts on its relative quality, or too soon for that? I know you like the Victor 7045. What other arms, if any, do you favor? In the late '80s/early '90s my ex business partner had a Goldmund Reference. I spent a lot of time at his house. Fabulous table, and he designed a set-up jig for the arm, but I think the arm was outperformed by the ET. The Souther, later bought by Clearaudio, seemed better with MCs than it should. It was often paired with the Veritas cart and I suspected the low frequency resonance reinforced the bass. Synergistic distortion? Never heard the Trans Fi or other air bearings. Soldering tonearm internal wire can be challenging. It's easy to mess up. Hell, stripping the wire can be a challenge. Some techs burn it off and clean the carbon residue. Feasibility depends on insulation type. The Sonus now has 1877 OFC. My tech did the rewire job. He's a lot better at soldering. The Sonus is an interesting arm. It looks like a Mayware Formula 4 on steroids. Stock, it's 4.1g eff mass. I have a custom headshell that takes it a little past 5g. Regards, |
Griff, Our posts crossed. There is no conversion between 10Hz cu and 100Hz. 100Hz cu is a measure of tracking ability at 100Hz, not compliance. We've converted some AT dynamic cu by measuring resonant frequency on known arms, and have a sliding conversion scale, but it doesn't always hold true, especially at the extremes. VTF might give a better idea and better yet a test record accurate even for an individual sample of a cart model. Regards, |
Better look out guys, this is getting interesting and you know what that means..... The FR7 isn't high cu either. A 981 @ 30cu is pretty high, work on the 801? Maybe some med/high cu? Maybe there's something about steel, like a mass/ rigidity combo, which boosts arm performance. I don't mind a little mod to adapt an arm. We do it routinely with carts - glue a stylus, pot a 103, etc. but an arm is held to a higher standard. I have a titanium arm which needs a little extra damping. So what? I like the arm, it's a keeper as far as I'm concerned. Speaking of standards, an arm is designed with a particular alignment geometry. When mounted at specified distance with mfg. alignment, the plane of the cantilever points directly at the pivot or the intersection of the pivots. To set up or align an arm in some other manner is to defeat the design unless it's coincidental. When you adopt a different alignment you're also changing effective length and offset angle. |
Griff, If 30cu is extremely high, what's the Sonus Blue/Gold or some ADC models @ 50cu, the ultimate high? I thought that description pertained to something else altogether. (chuckle) I haven't done all of these measurements, but a 103 is about 12cu @ 10Hz. The AT95 or any Clearaudio MM is 15cu, and the 440/150 is 18cu. To confuse things further, Ortofon publishes lateral cu. You mentioned something about the 801 bearings. Could you be more specific? Regards, |
Raul, Remember on Halcro's 'DD living dangerously' thread, it was apparent you didn't know S/N spec limitations of a turntable? Guess what? ** """" When you adopt a different alignment you're also changing effective length and offset angle. """"This kind of sentences speaks of that audiophile mediocrity/low knowledge level where we " audiophiles " are " swiming " through.** You've done it again. Regards, |
Raul, You're fond of calling other people ignorant, questioning their sensibilities and powers of discernment, yet your ignorance is so great you're like a child who skipped school. Look what you've done. Nearly a day has passed and the conversation has stopped except for Raul trying to prove his superior knowledge level. I was trying to give you an easy out, but you're tenacious like a bull dog ripping someone's pant leg. You quoted a sentence out of context. Ironically, that sentence happens to be correct. The only stipulation is mounting distance remains constant. I thought that was obvious from the context which wasn't about either of the Loefgren alignments, so put it to bed. You don't know what you're talking about. Now you have an explanation why a table S/N can be 92dB or whatever and you're saying I'm dogmatic? Ignorante! What happened at Lenco Heaven? There's a wild story on your MM/MI thread about your emotional problems and cat photos etc. I don't want to embarrass you, but you make it impossible not to. I think you need a time out from here to straighten out emotions. Why don't you take a break and find someone to talk to? I won't be back to this thread. I'm too busy now and can read about any further developments. I was serious when I said you have many friends here and I don't think people will hold it against you. Regards, |
Raul, Sorry, I gave you credit for being a little smarter than that, but you've proven me wrong. I wasn't planning to return to this thread and now I'm teaching remedial geometry. **Dear fleib: Not really. Let that I try to explain all that. As you I 'm talking of standards alignments as both Loefgren A and B solutions ( Baerwald/Loefgren. ** I wasn't talking about Loefgren alignments. **In those Loefgren equations the main target is to find out the precise offset angle and overhang with foundation/knowing the tonearm effective lenght ( L in the equtions. ) and radius of the Lp grooved surface ( most inner and outer LP groove recorded area. ). For difference between that L and the overhang the Loefgren solutions achieve the distance between tonearm pivot to TT spindle. The L does not change in those Loefgren standard solutions, WHAT CHANGED IS OFFSET ANGLE, PIVOT TO SPINDLE, AND OVERHANG VALUES.** What don't you understand? Effective length = pivot to spindle (mounting distance) + overhang (spindle to stylus). If mounting distance remains constant, then effective length (L) must change with a different alignment. The rest is nonsense. The Loefgren alignments are close in headshell length and angle, especially for arms longer than 235mm. |
As long as we're talking alignments, here's a post from Audio Circle: **Not sure if we talked about this on this forum - UNIDIN alignment is a legit alternate alignment. Nulls - 66.3, 112.5mm You can read something about this in Stereophile or Analog Planet and see the alignment error curves. It looks pretty good. I was playing with the numbers and what you won't read is that the alignment is nearly identical to Loefgren, but moved inward about 5mm. The distance between Loefgren nulls is 46.3mm. UNIDIN is 46.2mm. Nice to get away from Agon. What'shisname is really a block head. Guess every forum has one. I wanted to have the 3 standard alignments posted so no one would have to look them up. Here's another: **According to VE the nulls for the 507 II are 60.1 and 116.6mm. That puts the inner null next to Stevenson at the lead out, and the outer null is Loefgren. This should optimize the middle and end of the record.** Many people dislike Stevenson alignment, but you have to admit it's the best at the end where the grooves are crowded and the tip gets pinched. Some people prefer it. That would include Peter Pritchard (ADC/Sonus). He also recommended a low frequency resonance of 6.5Hz. That would put the resonance as far away from the audio band as possible, just above warps. If someone has a big fat spherical stylus or inner groove problems, Stevenson comes to the rescue, especially with a cart that emphasizes "musicality" over detail. No, this isn't about taste or practicality. This is about distortion. People use the terms alignment error and distortion interchangeably. That comes from Loefgren - his description. There's no denying the cantilever excites the generator and lack of tangency is undesirable, but what's the exact correlation? Does 2° of error correspond to 2% distortion, and what kind of distortion? The reason some people find those zero offset arms sound good, is reduction of torsional forces on the cantilever. Do linear arms solve these problems? If and only if, they can maintain tangency at all times and otherwise behave as a proper tonearm Re: mass, friction, etc. Something to think about. |
Someone is not paying attention. Dynavector nulls were just posted and they are not Stevenson. The inner null is close to it, but outer null is Loefgren B. How does this change tangency and alignment error? http://www.vinylengine.com/tonearm_database.php?make=Dynavector&mdl=&sort=2&eflo=&ef...= Click on the nulls to find out. Scroll down to the columns headed with the stock and standard alignments. Notice the odd relationships between various alignments with regard to eff length, offset, and overhang. What remains constant? Pivot to spindle = mounting distance. The equation is L = MD + OH. Where MD is mounting distance and OH is overhang. If L remains constant, then the values of MD and OH change for different alignments, but still total to equal L. Forget about Loefgren's papers, it's all right there. You're confusing yourself trying to reinvent the tonearm. If you start doing the math for different nulls, your arm will be released around the year 2127, or the 2nd of never. What interests me is the DV total alignment error - looks pretty good. They say "Distortion figures are calculated from samples of tracking error in the modulated groove area." Samples? Sounds like smoke and eyewash. Distortion analyzer? |
Dover, Interesting comment. The straight zero offset arms available today address lateral torsional forces. The ViV Rigid Float requires little or no antiskate as a result of this. Skating force is increased by cart offset, that is lateral cantilever angular difference between pointing at the pivot and pointing at offset angle. There is still skating because the cantilever is tangent to the groove at only one null point on an underhung arm, but it's said to be insignificant. The only arm I've heard of that addressed lateral and vertical torsion is RS Labs. That one had the pivot elevated so the zero lateral offset cantilever would also approximately be vertical zero offset. The trade off with alignment error is significant, but reviewers say it's worth the trade. Ironically, they also say the shorter version sounds better. This is supposed to be because reduction of length also reduces arm resonances, or something like that. It's conjecture but makes sense. My skepticism with distortion figures and alignment error correlations isn't based on these arms. There is necessarily a phase difference between channels with lack of tangency, but it seems to me any other distortion would be cantilever and tip dependent. Regards, |
Raul, My job is being a consultant to you? This is news to me, am I on the payroll? Maybe a flat fee for consultation, or maybe I misunderstand. I thought this thread is about high quality arms around $6K or less. It looks like all the DV arms have the same geometry and the 507 may look a little weird, but I don't care about that. I thought I was your geometry teacher - remedial 101. I guess not because you're assigning the curriculum. This is confusing, and to be honest, Griffithds would be a better consultant/teacher. He comes highly recommended and has experience in the aerospace industry. He's practically a rocket scientist. I'm quite sure he's forgotten more than I know about math, the problem is how much does he remember? Remember his post admitting to brain flatulence? Not much to worry about on that score though, he can consult from home. You know the bit about feeding the hungry - teach someone to farm and he can grow his own, or something like that? That was my teaching plan. Know any algebra? You're supposed to pass algebra before you take geometry. How can you solve an equation without algebra? I think you just push buttons without understanding and want someone to tell you which buttons to push? Know what an equivalency is - 2 sides of an equation? L = MD + OH L = 10" = 254mm. 254mm = pivot to spindle + overhang. L is your constant and you need 2 numbers that add to 254 for the other side of the equation. To find those numbers for any standard alignment go back to VE calculator and put in 254 for effective length. If that doesn't work find a 254mm arm in the database and click on the nulls. That will give the other numbers. That's the best I can do. My specialty is solid geometry and my brain is farting like crazy. They told me I was filling in for Professor Timeltel. I thought he was an English Lit prof. I think I was conned. Did Timeltel retire? I don't know what's going on, but Griffithds is your man. Regards, |
Dear Raul, You wound me deeply. I was the greatest tutor in all of the Americas, and look what I have become. I have failed you. Now I am just a hollow shell of a tutor, like an empty tortoise shell in the sand, I'm a dead tortoise tutor, not to say I tutor dead tortoises, but my tutoring, he is very sick. I thought I answered all your questions, but usted no entiende. Si me lo permite. Yes, the Loefgren calculations are correct. They are the basis of all the others. The spreadsheets, VE calculators are the same thing in different formats. Your answers should be the same. If you start out with L the spreadsheet or calculator will show you M distance, offset, error, etc. for each alignment. I don't have your spreadsheet. I told you how to access the calculator. You don't need to log in. Follow my instructions and it's all there. If you can't use the spreadsheet or calculator I suggest you build something else. How about a nice headshell holder display block? Regards, |
Lewm, Is this UNI like using 2 protractors? Seems to me no individual protractor can align for both Stevenson on the inner and Loefgren on the outer. Regards, |
