I know it's absolutely ok to use sapphire guides for your own use, it's just that, if you want to sell tonearms using sapphire guides to someone else, that person need to have the same care and be instructed on the thing very well so that accidents happen less often.It's just not reliable enough for commercial use withought a very good understanding of what sapphire operation means.
Last edited:
This is not a commercial product and I have no intention of making it so. I'm retired so have more time than money these days. It was a challenge to make a TA that out performs anything commercially available. Have I achieve that, I don't know because I have not heard a SAT CF-09. Is it better than an SME V and a Technics EPA-100, significantly better.
You shouldn't probably be too worried about SAT tonearm performance.Great reviews and hyped marketing aren't making great products too often ..If you like the sound of your cartridges it's all you need.Every single human have its own opinions and perceptions and very rarely two opinions in audio converge...I'm still pissed by the thing that i can't build a 2.5 grams tonearm withought counterweight as B&O made for its carts so i won't be able to hear the original cart as it was intended by B&O until i buy a B&O turntable with a working tonearm.Yet i'm very satisfied with what i could do even with very limited resources as using pcb flat tonearms.
Last edited:
If the balance of the tonearm is neutral, why does it not go deeper when you put the weight on it?
The carbide pivots are not pushing against balls. The carbide pivots are resting in M4 setscrews that have had a 0.5mm radius forged in the end and polished. The horizontal pivot is akin to a captive unipivot. Both pivots requires very close adjustment to ensure the pivot is not too tight or loose.
Last edited:
@alighiszem The reason the arm does not keep traveling down is the COG is coincident with both pivots so 4mg is not enough mass to move the COG far enough forward for the arm to keep moving down. 16mg however is enough for the arm to keep moving all the way down.
BTW 16mg is still lower than many commercial tonearms. Jelco spec about 20-30mg for their arms.
What is important with a TA is how much force is needed to start the arm moving, ie break bearing stiction. This arm that's 4mg to commence movement.
One easy way to determine if the arm is neutral balance is to float the TA and move it to any position. A neutral balance arm will stay where it's put.
If the COG is above the pivot the arm will have a tendency to move all the way up or down once it's no longer horizontal. A low COG and the arm will go back to horizontal and pendulum.
BTW 16mg is still lower than many commercial tonearms. Jelco spec about 20-30mg for their arms.
What is important with a TA is how much force is needed to start the arm moving, ie break bearing stiction. This arm that's 4mg to commence movement.
One easy way to determine if the arm is neutral balance is to float the TA and move it to any position. A neutral balance arm will stay where it's put.
If the COG is above the pivot the arm will have a tendency to move all the way up or down once it's no longer horizontal. A low COG and the arm will go back to horizontal and pendulum.
Thanks, I was curious about ball bearings, due to the first image in post #38, which looked like a miniature ball bearing of some sort. I just ended up biting the bullet and buying an arm finally after fooling around waiting for a year and a half. While I wait for it to arrive, I think I’m still going to make one, and have something to compare. This thread and some others I have seen have been interesting to follow to give me ideas.
The first image in post #38 is taken from my USB microscope. It's a pic of the inside of the M4 setscrew. The green dots you can see are the reflection of the LED's in the microscope.
Making a TA is a great way to learn. Every single TA is a compromise and deciding what compromise you are prepared to live with and the equipment you have to make such TA will determine what type you can make.
Mechanical Linear Trackers are the easiest to build with minimal tools. Unipivots are also easy to build as there is no requirement to line up pivots. Gimbal bearings are the hardest as they need micron precision to ensure the pivots are lined up or stiction increases to unacceptable levels.
Making a TA is a great way to learn. Every single TA is a compromise and deciding what compromise you are prepared to live with and the equipment you have to make such TA will determine what type you can make.
Mechanical Linear Trackers are the easiest to build with minimal tools. Unipivots are also easy to build as there is no requirement to line up pivots. Gimbal bearings are the hardest as they need micron precision to ensure the pivots are lined up or stiction increases to unacceptable levels.
Mechanical linear trackers are much to fidgety for me, even though simple in principle. I like things that simply work and do their job with minimal effort on my part. But I’m also curious to push the envelope and like to tinker with things sometimes. I have access to any tool I could wish for, time and motivation are more of an issue.
I'm not a fan of wood for tonearm wands. A TA wand needs to be as rigid as possible. Wood will bend microscopically more than AL. The other reason for choosing AL is to provide an easy path away from the headshell (HS) for vibration energy. This energy must be dealt with to reduce to a minimum any reflected energy back to the HS. This TA deals with the energy in CW stub and CW. The brass CW stub is bolted to the arm wand with a disk of Lead between the 2 and the CW is made from Lead. Lead significantly improves energy transfer between different metals. In order to reduce energy reflected back to the armwand the CW stub is profiled so reflected energy strikes the Lead disk at greater than the Critical Angle meaning most of the energy is reflected back to the CW stub. Any energy that does make it back to the wand is dealt with via the differing tapers in the wand which causes the energy to bounce around in the wand.
I am currently using a Pickering XSV-3000 body with a Stanton CS-100 stylus.
Even though this TA is massively heavy armwand and CW stub weigh nearly 200g and the CW is nearly 300g it's effective mass is on the low side of medium at about 11g. This is due to the way the mass in the TA is distributed. A lot of attention was paid to mass distribution in the arm so as to produce a TA that is as neutral as possible.
I am currently using a Pickering XSV-3000 body with a Stanton CS-100 stylus.
Even though this TA is massively heavy armwand and CW stub weigh nearly 200g and the CW is nearly 300g it's effective mass is on the low side of medium at about 11g. This is due to the way the mass in the TA is distributed. A lot of attention was paid to mass distribution in the arm so as to produce a TA that is as neutral as possible.
The hardest part of the build for me was getting the pivots to operate with very low static friction. The pivots need to be lined up within 10um or the static friction increases. I spent many hours on the pivots, profiling the radii then burnishing and polishing.
I'd be more than happy to help you duplicate it.
I'd be more than happy to help you duplicate it.
This is absolutely incorrect. My sister is a gemologist and also is an expert on the hardness and durability of all stones, metals and their strengths. Corundum is the strongest and longest lasting element that can be formed into industrial bearings PERIOD. She had to laugh at the idea that rubies were delicate. At a rating above 9 and lower than diamond at 10 which cannot be formed into bearings, the ruby is the industry standard for strength an durability https://www.industrialjewels.com/ruby-jewel-bearing/. Tungsten is not even in ballpark of this level of strength and ability to keep it's shape under even high duress over time. Brittle they are most definitely NOT. This is also why the sapphire bearing of the SOTA tables last forever under a heavy platter with no degradation unless there is a problem in manufacture. The same problem with 1970s cartridges which crush the newer units of idiotic pricing with Sapphire cantilevers that measured on a B&K at 35db separation, frequency response from 15-50Khz and tracked at 100 or even better at 315hz or any frequency and the best tracker which is first before being able to extract the details of which Tracking ability ALWAYS comes first before getting to the nuances, with the Shure V15 type VMR with hollow beryllium cantilever and the best attachment of a superior diamond compared to the competition and a weight of the entire moving structure less than 1/2 of most MC garbage today, able to track at 90 at 1 gram and 60 at .5 gram. Doug Sax stated the best cartridge he ever heard was the Stanton 881S with the sapphire cantilever and stereohedron diamond. The EPA-100 is able to move laterally and vertically at 3mg deflection but still stays in the groove better than any arm ever made. It is capable of any compliance but low compliance on a disc is death to music and most MC at stratospheric prices are lucky to read 60muM at 315 tracking at 2.5 grams destroying the delicate micro ridge and cutting new grooves into the vinyl. (Vinyl should be played once and let return to original form and the weight / sq. in is very high. The Micro Ridge is essentially from Fritz Geiger and his stylus of which is now called an Ortofon Replicant.
The very best part of good engineering a platter is the flywheel effect which Technics, Kenwood (L-07D the best turntable arm combination ever made), and the Denon direct drives are fetching very very high prices. The "hunting" is nothing as once the initial torque is applied the platter does NOT exceed the desired speed and take microvolts to keep at speed and the best platters are those with the majority of weight on the outer rim and are absolutely balanced. Sound deadening materials have been in Technics tables for a considerable amount of time and the SL-1200mk V for instance is layered with it above and below within the base and also has a VTA with Lock. It is too bad that these older companies that knew what they were talking about in physics, chemistry and electrical engineering along with their vertical manufacturing are now lost. Look at the L-07D and the anti-vibration technology in the entire system including the most sophisticated head shell ever made at https://www.l-07d.com
https://www.diyaudio.com/community/threads/diy-4-point-pivoting-arm.375071/post-6808955
I thought so about the l-07d in the past but l-07d owners very often say they need to change the original tonearm as they don't like it that much...
I have an EPA100 it's a very good arm and according to the manual sensitivity is 5mg. My DIY arm with the carbide pins and M4 setscrew pivots is 7mg, so all in all a good result, especially for an arm this massive.
With the sapphire / carbide pivots the problem was not the sapphire cups but the but the pivot pins were too small for the arm. Once the carbide broke it damaged the cup.
I'm experimenting with headshells ATM in an attempt to reduce needle talk. The arm wand is massive (the wand has a 1.5mm wall at the HS and 10mm at the bearing) so I doubt the wand is resonating, so the HS is the likely culprit.
With the sapphire / carbide pivots the problem was not the sapphire cups but the but the pivot pins were too small for the arm. Once the carbide broke it damaged the cup.
I'm experimenting with headshells ATM in an attempt to reduce needle talk. The arm wand is massive (the wand has a 1.5mm wall at the HS and 10mm at the bearing) so I doubt the wand is resonating, so the HS is the likely culprit.
I really enjoy the topic of MM cartridges. I hope you can write more in a separate thread. (Perhaps with less run on sentences? 😁) Thanks!