Dover: I expect that the X88D was a typo for XL-88D. It could have also been a prototype, but XL-88D production started in either 1979 or 1980, so probably a typo rather than a proto (smile).
BTW, Mori-san is now doing a cartridge project with Takai-san of Final Audio. The cartridge features Mori's hallmark figure-8 coil, and I assume that the armature is non-permeable. I know that both Mori-san and cartridge were in the Final Audio room at Munich this year. I'd have loved to listen to Mori's latest, but unfortunately this year I decided to stay at home because I wanted to make more progress on design and development work.
Fleib: Before going further, I think that it is better if you first gain a basic understanding of what cantilever design is, next an understanding of the various issues that influence cantilever design (which may not be obvious to someone who doesn't design cantilevers). Talking about numbers without understanding what they mean and why will confuse rather than enlighten.
Please take a look at the following illustration of a cantilever cross-section. I wanted to find a better drawing, but thise was the best that I could come up with on short notice.
http://www7a.biglobe.ne.jp/~yosh/images/4209669.jpg
#1. cantilever
#1a. joint (or joint pipe)
#2. stylus
#3. armature (probably magnet for this particular cartridge)
#3', 3". suspension wire sleeve
#6. damper
#7. suspension wire
#8a, 8b. suspension wire holder (or stopper pipe)
The movement of the cantilever is accomplished by pivoting around the free section of the suspension wire (visible in the center-left section of the damper). But since the suspension wire is being pulled constantly by VTF and the drag of the LP groove on the stylus, it needs to be glued and crimped in place. There will be four such crimp / glue sections, at the heads and tails of the suspension wire sleeve and the stopper pipe, respectively.
Since a pipe cantilever is hollow inside, it is feasible to extend the pipe all the way back to the rear face of the armature, as we see in the linked drawing. But with solid rod cantilevers, the designer is forced to end the cantilever before the suspension wire sleeve (due to the presence of the suspension wire and the crimp), and use the joint pipe to connect the two elements together.
To envision what a solid rod cantilever would be constructed like, imagine that the outer diameter of the suspension wire sleeve is made equivalent to the outer diameter of the cantilever, with the tail of the cantilever rod touching the head of the suspension wire sleeve (more accurately it would be the crimped end of the suspension wire). The inner diameter of the joint pipe is made equivalent to the outer diameters of the cantilever rod and suspension wire sleeve.
The length of the joint pipe is up to the designer, which confers an additional measure of control over rigidity by setting the distance over which the joint pipe overlaps the cantilever (thereby creating a double-walled structure). Extending the joint pipe forward adds mass as well as rigidity, and it is up to the designer to make his choices, and to ponder why.
Choosing less than maximum cantilever rigidity (either via cantilever or joint pipe), along with allowing a bit of excessive movement in the suspension pivot, tends to make for a cartridge that is both easier to voice and easier on the tonearm. Conversely, reducing cantilever transmission losses and shortening the free length of the suspension wire tend to create a more peaky cartridge, in many cases with a visibly rising peak at the top end. However, when it comes to picking up everything that is on the LP, there is no doubt that a more rigid cantilever and a more tightly defined pivot point are superior.
When it comes to this kind of choice, it is very much about the designer's philosophy regarding sound reproduction, and to some extent, his subjective sonic preferences. And maybe it also depends on how much importance he places on measurements. A designer (or cartridge builder) that likes a smooth and friendly sound or wants perfectly flat measurements is likely not going to choose a super-stiff cantilever and super-short suspension wire.
Eddy currents can also affect the frequency response, again with some measure of lossiness or high-frequency core losses being useful if a flat frequency response is a high priority for the designer.
Measurable frequency response is affected by stylus tip mass, cantilever resonant characteristics (material and dimensions), overall cantilever length, overlap between cantilever and joint pipe, tightness of suspension pivot point, damper characteristics, eddy losses in the magnetic system, etc.
Measurable frequency response is also affected by the room temperature, and the LP groove diameter.
The subjective frequency response is affected by the cartridge body construction (materials, shape, presence and locations of voids etc), coil and armature materials and processing, choice of glues and bonding lacquers, and so on. In addition to everything above.
Regarding the Atlas's stylus mounting platform, it is a reinforcing metal plate added specifically to make it much harder for users to shatter the diamond stylus block, or break the adhesive joint bonding the stylus to the cantilever.
Until around the year 2000 I was using Ogura PA stylii with blocks that measured 0.06Wx0.06Lx0.5mmD. This is a comparable size and mass to what was used inside the Denon DL-1000A. The stylii had nice performance, but more than a few of the cartridges were returned to us because the diamond block had shattered, or the glue joint had failed. In many cases the failure was visibly due to user abuse (or perhaps abuse inflicted by their tonearms), but we did eat the rebuild costs for some of these cartridges. Eventually we came to the regrettable conclusion that the 0.06Wx0.06Lx0.5mmD diamond block size was simply too delicate for the kind of treatment that our cartridges were being subjected to in the field.
For this reason, from the Clavis Evolve 99 onward we shifted to a somewhat larger diamond block that measures 0.08mmWx0.12mmLx0.5mmD, and this is the size that we still use today (with the exception of the Delos, which uses a Namiki stylus rather than Ogura). It has been more rugged than our older 0.06Wx0.06Lx0.5mmD size, but our service records still showed that more cartridges that we would have liked were being returned due to breakage of the glue joint or of the diamond block.
The additional metal plate that you saw in the Atlas photo is a means to further increase the ruggedness of the larger-size 0.08mmWx0.12mmLx0.5mmD and of its glue joint. Hopefully this time it will be enough.
You are welcome to calculate the stylus tip masses if you feel so inclined.
kind regards, jonathan
BTW, Mori-san is now doing a cartridge project with Takai-san of Final Audio. The cartridge features Mori's hallmark figure-8 coil, and I assume that the armature is non-permeable. I know that both Mori-san and cartridge were in the Final Audio room at Munich this year. I'd have loved to listen to Mori's latest, but unfortunately this year I decided to stay at home because I wanted to make more progress on design and development work.
Fleib: Before going further, I think that it is better if you first gain a basic understanding of what cantilever design is, next an understanding of the various issues that influence cantilever design (which may not be obvious to someone who doesn't design cantilevers). Talking about numbers without understanding what they mean and why will confuse rather than enlighten.
Please take a look at the following illustration of a cantilever cross-section. I wanted to find a better drawing, but thise was the best that I could come up with on short notice.
http://www7a.biglobe.ne.jp/~yosh/images/4209669.jpg
#1. cantilever
#1a. joint (or joint pipe)
#2. stylus
#3. armature (probably magnet for this particular cartridge)
#3', 3". suspension wire sleeve
#6. damper
#7. suspension wire
#8a, 8b. suspension wire holder (or stopper pipe)
The movement of the cantilever is accomplished by pivoting around the free section of the suspension wire (visible in the center-left section of the damper). But since the suspension wire is being pulled constantly by VTF and the drag of the LP groove on the stylus, it needs to be glued and crimped in place. There will be four such crimp / glue sections, at the heads and tails of the suspension wire sleeve and the stopper pipe, respectively.
Since a pipe cantilever is hollow inside, it is feasible to extend the pipe all the way back to the rear face of the armature, as we see in the linked drawing. But with solid rod cantilevers, the designer is forced to end the cantilever before the suspension wire sleeve (due to the presence of the suspension wire and the crimp), and use the joint pipe to connect the two elements together.
To envision what a solid rod cantilever would be constructed like, imagine that the outer diameter of the suspension wire sleeve is made equivalent to the outer diameter of the cantilever, with the tail of the cantilever rod touching the head of the suspension wire sleeve (more accurately it would be the crimped end of the suspension wire). The inner diameter of the joint pipe is made equivalent to the outer diameters of the cantilever rod and suspension wire sleeve.
The length of the joint pipe is up to the designer, which confers an additional measure of control over rigidity by setting the distance over which the joint pipe overlaps the cantilever (thereby creating a double-walled structure). Extending the joint pipe forward adds mass as well as rigidity, and it is up to the designer to make his choices, and to ponder why.
Choosing less than maximum cantilever rigidity (either via cantilever or joint pipe), along with allowing a bit of excessive movement in the suspension pivot, tends to make for a cartridge that is both easier to voice and easier on the tonearm. Conversely, reducing cantilever transmission losses and shortening the free length of the suspension wire tend to create a more peaky cartridge, in many cases with a visibly rising peak at the top end. However, when it comes to picking up everything that is on the LP, there is no doubt that a more rigid cantilever and a more tightly defined pivot point are superior.
When it comes to this kind of choice, it is very much about the designer's philosophy regarding sound reproduction, and to some extent, his subjective sonic preferences. And maybe it also depends on how much importance he places on measurements. A designer (or cartridge builder) that likes a smooth and friendly sound or wants perfectly flat measurements is likely not going to choose a super-stiff cantilever and super-short suspension wire.
Eddy currents can also affect the frequency response, again with some measure of lossiness or high-frequency core losses being useful if a flat frequency response is a high priority for the designer.
Measurable frequency response is affected by stylus tip mass, cantilever resonant characteristics (material and dimensions), overall cantilever length, overlap between cantilever and joint pipe, tightness of suspension pivot point, damper characteristics, eddy losses in the magnetic system, etc.
Measurable frequency response is also affected by the room temperature, and the LP groove diameter.
The subjective frequency response is affected by the cartridge body construction (materials, shape, presence and locations of voids etc), coil and armature materials and processing, choice of glues and bonding lacquers, and so on. In addition to everything above.
Regarding the Atlas's stylus mounting platform, it is a reinforcing metal plate added specifically to make it much harder for users to shatter the diamond stylus block, or break the adhesive joint bonding the stylus to the cantilever.
Until around the year 2000 I was using Ogura PA stylii with blocks that measured 0.06Wx0.06Lx0.5mmD. This is a comparable size and mass to what was used inside the Denon DL-1000A. The stylii had nice performance, but more than a few of the cartridges were returned to us because the diamond block had shattered, or the glue joint had failed. In many cases the failure was visibly due to user abuse (or perhaps abuse inflicted by their tonearms), but we did eat the rebuild costs for some of these cartridges. Eventually we came to the regrettable conclusion that the 0.06Wx0.06Lx0.5mmD diamond block size was simply too delicate for the kind of treatment that our cartridges were being subjected to in the field.
For this reason, from the Clavis Evolve 99 onward we shifted to a somewhat larger diamond block that measures 0.08mmWx0.12mmLx0.5mmD, and this is the size that we still use today (with the exception of the Delos, which uses a Namiki stylus rather than Ogura). It has been more rugged than our older 0.06Wx0.06Lx0.5mmD size, but our service records still showed that more cartridges that we would have liked were being returned due to breakage of the glue joint or of the diamond block.
The additional metal plate that you saw in the Atlas photo is a means to further increase the ruggedness of the larger-size 0.08mmWx0.12mmLx0.5mmD and of its glue joint. Hopefully this time it will be enough.
You are welcome to calculate the stylus tip masses if you feel so inclined.
kind regards, jonathan

