Weather it will have any effect will depend on the length of the slots in the head portion when the cartridge is mounted. Their slotted for a reason. 5mm is only 2 tenths of an inch. Not much. Most slots are quite a bit longer that that so if using the recommended mounting distance would have placed the cartridge in the center or even forward of center of those slots, you just might not have a problem.
Regards. |
The ''Zupreme'' sold by LP/Gear has the slots quite a bit forward. This head shell is Magnesium with the screw for azimuth adjustment. Litz leads and are the same head shell as the Sumiko's. Their just not branded as such and sell for $50 instead of the $90 that Sumiko's get!
In my opinion, the best head shell available!
Regards, |
Lewn,
The problem with 'trusting' the given dimensions for spindle to pivot is that it is expected that everything else will just automatically falls into place (dimensionally). Well, that isn't always the case. What you are trying to accomplish is for the stylus tip to correctly trace a given curve line. BTW: All tone arms with a cartridge mounted will make a perfect circle it they were being used to draw with. You want the stylus tip to follow a section of that circle (part of that curve), in which the record is going to be placed on. The setting up of the spindle to pivot distance only ''assumes'' that the stylus tip is then going to follow this curve. It just might if you only use the head shell that was or is provided by the tone arm manufacture. That is because he has provided those head shell ''slots'' to be in a position that would allow you to mount a cartridge so that it will follow that curve. Use some other head shell and those slots might be in the wrong place. I use the Mint LP Tracker or sometimes referred to as the Best Tracker as my cartridge set-up device. If you were to 'hold' that stylus tip onto that curve line, and you had the cartridge mounted in a head shell with very long slots, could you not move that pivot point in or our (closer to or farther away from the spindle), without moving that stylus tip? Yes,moving it out 6 feet would change the curve but we are not talking feet. Not even inches. We are talking 5 milimeters. The change in the curve would be even smaller that what the difference is between the Stevenson and the Baerwald. Not to even mention all the other variable alignment protractors that are out there! I find it more important to decide what head shells you wish to use, and then set up for it. Not the other way around and have your hands tied sort of to speak, being forced to use what ever head shell (slot position), that the manufacture decided upon. I like Magnesium for head shell material, and I like to have adjustable azimuth. Most tone arms do not provide this Azimuth adjustment feature. My Graham arm does, but neither my JVC 7045 or my Lustre GST-801 do. I do not want to shim head shells, so I have chosen the Sumiko's, or cheaper yet, the 'Zupremes'.
There is no industry standard as to where these head shell ''slots'' are suppose to be. This is sad but true.
The JVC 7045 tone arm came with its own head shell. I marked a dummy arm board (made out of plywood), per the spindle to pivot dimensions given and drilled it. I then mounted the arm, the provided JVC head shell with a cartridge installed. It followed the Mint tracker curve perfectly. I then remove the JVC head shell and mounted a head shell with a cartridge that was not a JVC head shell only to discover that I could not get the cartridge to slide far enough back in the slots to trace this curve. I tried several other brands of head shells that I have with cartridges mounted in them and none of them would allow me to position the cartridge so that it would trace that curve line. So where is the problem? Is it the spindle to pivot distance dimension? Well, if you only use the supplied head shell from JVC, then the answer is 'No'. But if you wish to use head shells supplied by other manufacturer's then the answer is 'Yes' . That spindle to pivot dimension is wrong. I did finally drill my arm board but I didn't use the supplied dimension given on the drilling templet. I drilled the hole so that my cartridges sit in the center of the slots when they are mounted in one of these Sumiko's. The stylus tip traced that Mint Tracker curve line perfectly. I don't know nor do I care what the spindle to pivot dimension is. I only care that it traces the curve correctly.
Regards, |
I'm sorry Raul, but I do not listen to 'white papers' so I do not know what they sound like. I listen to records and know what I 'hear'!
What you state about there only being one correct number for overhang and offset angle of any particular tone arm length is true. But that doesn't meant that the person who came up with those numbers on my JVC templet are the correct ones! Nor does that meant that the numbers for set-up in the tone arm in this thread are the correct numbers because they are ''only'' numbers printed on a form. Nothing more, nothing less! The proof is in how it traces after set-up. Not how it measures in regards to some printed number on a form! The arm in question was not actually measured so how do we know what its 'overhang and offset angle' should be? You 'assume' that its length is what is stated on the templet. You 'assume' that the dimensions stated on the templet is correct. You 'assume' that to drill this hole for the arm to mount into will be correct. Sounds to me like you are ''assuming'' far to much and not doing enough 'actual measuring! After drilling, it either tracks that Mint Tracker correctly, or it doesn't. That is all, and nothing more. If to do so, some other number had to be used to drill the mounting hole distance from the spindle for the arm, so be it. The point is to track the curve line. Not ''what does it measure''?
Regards, |
Lewm,
I should also mention that the supplied head shell from JVC also is usable after my drilling. But instead of the cartridge being mounted in the center of their slots, the cartridge is now mounted near the forward most location of their slots. All other brands of head shells allow the cartridges to be mounted some where around the center. Some more forward, some more towards the rear. But all will follow the Mint Tracker curve perfectly.
Regards, |
Hi Lewm
My main point is not to dispute overhang dimensions but to dispute the assumption that because a templet says a arm is a certain length then the arm that you are mounting "IS" that length. Measure it and then determine what the overhang is suppose to be for the arm that you are mounting. Not some factory manufactured arm that has been made from tooling that has +/- tolerances built into the assembly tools and possibly put together by some guy on Monday morning with a hangover!
BTW: I also agree with what Raul and you have stated. But text book definitions are not what the question here was. I think the arm in question does not measure in length for what the overhang dimension given is suppose to measure. This particular arm just might sound better positioned at a location other than what is printed on a templet.
Regards, |
Raul, read the opening post. A tone arm was bought. Should he drill the mounting hole at the given dimensions per the manual? You say yes. Why? Because the manual says so? Sorry but mistakes often get made on drawings. I'm a Aerospace engineer and I have correct hundreds. Who said that the arm in question actually measured what the manual says they all are expected to measure? To drill a hole in your arm board because some stranger says that is where most of the arms he has manufactured should be located is just plain wrong! That arm should be measured. S2P determined. Then drilled. It is not rocket science. It is just plain common sense. We are not talking text book geometry here. We are talking about one particular tone arm.
Regards, |
Lewm,
If you are given a spindle to pivot distance mount point of 215mm, then there must be a arm length that was used by the person who approved that 215mm position. Measure your arm and verify that it measures what is assumed to be its length. If it doesn't measure that length, and I have one that didn't, then that mounting hole you are about to drill (using that 215mm dimension), is going to be in the wrong place.
My JVC UA 7045 tone arm is the arm that has convinced me to do the critical check and not just 'blindly trust' those printed templets.
On the templet for the JVC 7045, the spindle to pivot dimension is 130mm. The templet shows that the head shell arm lift (which btw, attaches to the cartridge), would then be in the center of the slots. I drilled my dummy plywood armboard as stated. 130 mm from center of spindle to pivot point. The cartridge when mounted in the Technics head shell, when set-up using the Mint Tracker curve device sat in the most forward locating of the slots. This is and of itself would not be a problem if I only used one cartridge and had only this one head shell. But I own 80+ cartridges. All mounted on various head shells. What I discovered is that this particular Technics head shell has its slots are not only longer, but are also positioned 50mm farther to the rear than any other head shell I own. Its most forward cartridge location position is to the back side of some of my other head shells and beyond the slots on most others. I even have other Technics head shells who's slots do not even come close to this original head shell that came with this tone arm.
Now ask your self. What is it that you want to do? If you are using a curve checking device to set up cartridges with, then is that not what your goal is? To set the cartridge so that it traces that curve.
I wanted to know why no other head shell will work with this arm except the one provided by Technics if that is, I drilled my arm board where I am being told to drill my arm board via their templet.
What I discovered is that my arm does not measure in length what it states it to be on that templet. It is slightly long. How long? By close to 5mm. I thought about removing the head shell collar and machining the end of the arm tube to shorten it by this 5mm. (The company I worked for has a rather large machine shop so I could have pulled in a favor and had this done for free). But why take that route. Why chop up the arm when it was obviously the numbers on that templet were not representative of what my arm measured. Why not just take the arms current measurements and reconfigure that spindle to pivot distance so the the hole I drilled actually is where is should be in reference to my actual arm length. Not where I am being told to drill it. My arm hole currently measures 135mm from spindle to pivot. 5mm more from the spindle that stated on the templet. All my head shells, now are usable. Even that original Technics allows the cartridgde to be mounted closer to what is depicted on the templet. When I state ''are usable'', I am referring to setting them up correctly with the use of the Mint Tracker. If the stylus tip deviates from that curve line anywhere on that line, whether it be near the spindle or near the records edge, then it is not set up correctly.
I have a picture taken of the original Technics head shell sitting along side a Sumiko head shell. Give me an email address and I will gladly send it to you so that you can see for your self. Once you see it, then picture in your mind if a cartridge was mounted in the center of the slots on the Technics, where would it be in the Sumiko which is sitting right along the side of it.
Now put yourself in my place at the time I was trying to figure out where in the hell to drill this hole. At that moment in time, where did the actual error lay? Was it the arm length? It might be correct pertaining to the drawings being used to actually manufacture the arm. Then Is it the drilling templet that is wrong? Would you have just blindly gone ahead and drilled that S2P distance hole as stated by the experts who included this templet with the arm? Well there is an error here somewhere and it certainly wasn't going to be the hole that ''I'' drilled!
Any other questions? Just ask.
BTW: You have resurfaced memories of this experience that I had sincerely tried to forget! (gran)
Regards,
|
Lwem,
Who exactly are you to trust if you have bought a tone arm in regards to setting it up? 'dangcaoguyen', the gentleman who initiated this thread, provided the information given to him and and asked if he could move the mounting hole over 5 mm? Then gave reasons why when mounted using the supplied set-up dimensions, His Quote
"the cartridge could not reach the cross point on my Dr. Feickert NG Protractor (I extended the cartridge all the way out from the Pivot) it was 4mm short. Unless i have a longer head shell or i will have to mount the arm 4mm closer than spec. (5mm to be sure)".
Sounds rather familiar to me!!!! Once you digest my thread, it should also sound familiar to you.
I addressed his question. I didn't expect others to give a destitation of text book arm geometry! He wasn't asking for a schooling in arm design theory but just a simple answer to what he discovered. His suggestions and discoveries, mirror mine!
Regards, |
Raul,
Quote:
Dear Dangcaonguyen: """ I mounted the arm 5mm shorter than manufactor reccomedation. The result was terific. """
IMHO what it's terrific down there are only " terrible " and high distortions not real music information. End Quote:
This is your idea of helpful? To criticize by questioning his findings after his deviation from the printed hole location. Did you actually hear what his system sounded like? It his system. If it sounds terrific to him, then I believe him. But to tell him that that what he is really hearing is ''terrible'' and high distortions not real music information is plain B/S!
Regards, |
ebm,
You are correct if that is what the final setup actually measures. That the position of his actual arm is 5mm out of the correct spindel to pivot dimensions for the length of his actual arm.
5mm off is 5mm off! But what is implied from the beginning of this thread is that there is 5mm difference between the the information given to make this setup and what the actually set became! One of the two options is right and the other was wrong. Is it the final position of the arm that is wrong? The owner of the arm says it sound terrific in its current location. This location is 5mm off from what was stated for it to be positioned. Because 'crappy sound' has not become the outcome of him moving the mounting hole over by this 5mm, then I would say that the spindle to pivot distance number he has been given was incorrect. His is not incorrect to have set up his arm correctly, only incorrect for not using the numbers supplied. If 'not crappy sound' is what his goal was, then what he did was correct. If following supplied dimensions was his goal, the he was wrong. I would prefer the 'not crappy sound' outcome over the following of supplied dimensions!
regards, |
