Hi again Neil:
>I do think the two-magnet design precedes the single-ring (not absolutely sure)
In general it doesn't (as I mentioned about the Philip GP-922 of the late 1970s), and I believe that the AF (IIRC) which I occasionally used in the early 1990s was Transfiguration's first product. This was definitely of the single-magnet type. This is not to say that Transfiguration's present single-magnet design has been revised and improved substantially - it most probably has.
>As for the tension string, all I know is I never saw one in any of the Temper series diagrams.
I also sometimes make drawings for the purpose of explaining technical matters to the general public, and when doing so, I normally leave out details that are not relevant to the issue being discussed. Including too many irrelevant details that the reader has never heard of is a hindrance to comprehension. I wouldn't be surprised if Transfiguration is doing the same thing.
There are companies who have used non-tension wire suspension systems, like Ikeda, Satin, and Glanz, but in these cases the use of a non-tension wire suspension system almost always required an accompanying revision in overall mechanical structure, which is quite obvious if you open up the cartridge and peek inside. Sometimes things are so obvious that you don't even need to open up the cartridge.
>I don't think I can agree with that (remaining content deleted for brevity)
That's not how a cartridge suspension and damping system works. First keep in mind that a cantilever only moves up (pull) and down (push) - there is no "pull" or "push" in the strict sense of the words. If a cartridge suspension is in a state that it really allows pull and push to happen, it is broken.
>because when you 'pre-compress' the suspension material by applying tension to the string/wire, the suspension material will always be in compression (just more or less of it.)
Next, you are confusing the dampers with the suspension wire. The suspension is a piece of flexible and usually springy wire (sometimes of metal, sometimes not), which is stiffened over most of its length so that only a very short section can actually move. This moving part is the pivot point. The length and placement of the pivot point is defined by how the cartridge designer draws up the cantilever assembly design. It doesn't have anything to do with the dampers. The dampers are normally elastomer donuts or disks that fit over the stopper pipe that secures and stiffens the suspension, and they will be pulled up snugly against the core (armature) and coils.
The suspension wire is deliberately designed to be too soft to support the tracking force, and it needs extra support from the dampers. To supply this support, the cartridge builder pushes the core and coils rearward so that the dampers are compressed between the core & coils and the magnet (or yoke, or cartridge structure). There's your "pre-compression". This is done as a matter of course by every cartridge builder that I know of - it isn't unique to anyone.
>What's important here is that this strategy moves the 'virtual pivot point' closer to the axis of the coil, instead of the traditional position behind the coil.
As I stated earlier, the position of the pivot point is determined when the designer makes the drawing for the cantilever assembly. Stiffening most of the suspension wire and leaving only a very short, precisely made length for movement is a far better strategy for defining the pivot point than relying on damper compression (which changes according to the individual damper - dampers are neither precise nor consistent parts).
However, the free length of the suspension wire is a somewhat ambivalent choice for the designer. Kept short, it offers more accurate transduction, but puts a greater strain on the tonearm regarding tracking. Kept a little longer, the transduction is less accurate, but the tonearm has an easier time. I personally keep the suspension wire as short as I can, in the full awareness that some tonearms may have difficulties with my cartridge designs as a result. Other designers that I have talked to prefer to keep the free length of the suspension wire a little longer, for better compatibility with a wider range of tonearms.
>Miyajima and (I think) ZYX are two other makers who have incorporated this idea as well, although using different methods to achieve it.
Miyajima appears to be using a suspension concept similar to the old Glanz designs (check out US patent 27437). ZYX seems quite orthodox to me, and there is nothing wrong with that.
hth, jonathan carr
>I do think the two-magnet design precedes the single-ring (not absolutely sure)
In general it doesn't (as I mentioned about the Philip GP-922 of the late 1970s), and I believe that the AF (IIRC) which I occasionally used in the early 1990s was Transfiguration's first product. This was definitely of the single-magnet type. This is not to say that Transfiguration's present single-magnet design has been revised and improved substantially - it most probably has.
>As for the tension string, all I know is I never saw one in any of the Temper series diagrams.
I also sometimes make drawings for the purpose of explaining technical matters to the general public, and when doing so, I normally leave out details that are not relevant to the issue being discussed. Including too many irrelevant details that the reader has never heard of is a hindrance to comprehension. I wouldn't be surprised if Transfiguration is doing the same thing.
There are companies who have used non-tension wire suspension systems, like Ikeda, Satin, and Glanz, but in these cases the use of a non-tension wire suspension system almost always required an accompanying revision in overall mechanical structure, which is quite obvious if you open up the cartridge and peek inside. Sometimes things are so obvious that you don't even need to open up the cartridge.
>I don't think I can agree with that (remaining content deleted for brevity)
That's not how a cartridge suspension and damping system works. First keep in mind that a cantilever only moves up (pull) and down (push) - there is no "pull" or "push" in the strict sense of the words. If a cartridge suspension is in a state that it really allows pull and push to happen, it is broken.
>because when you 'pre-compress' the suspension material by applying tension to the string/wire, the suspension material will always be in compression (just more or less of it.)
Next, you are confusing the dampers with the suspension wire. The suspension is a piece of flexible and usually springy wire (sometimes of metal, sometimes not), which is stiffened over most of its length so that only a very short section can actually move. This moving part is the pivot point. The length and placement of the pivot point is defined by how the cartridge designer draws up the cantilever assembly design. It doesn't have anything to do with the dampers. The dampers are normally elastomer donuts or disks that fit over the stopper pipe that secures and stiffens the suspension, and they will be pulled up snugly against the core (armature) and coils.
The suspension wire is deliberately designed to be too soft to support the tracking force, and it needs extra support from the dampers. To supply this support, the cartridge builder pushes the core and coils rearward so that the dampers are compressed between the core & coils and the magnet (or yoke, or cartridge structure). There's your "pre-compression". This is done as a matter of course by every cartridge builder that I know of - it isn't unique to anyone.
>What's important here is that this strategy moves the 'virtual pivot point' closer to the axis of the coil, instead of the traditional position behind the coil.
As I stated earlier, the position of the pivot point is determined when the designer makes the drawing for the cantilever assembly. Stiffening most of the suspension wire and leaving only a very short, precisely made length for movement is a far better strategy for defining the pivot point than relying on damper compression (which changes according to the individual damper - dampers are neither precise nor consistent parts).
However, the free length of the suspension wire is a somewhat ambivalent choice for the designer. Kept short, it offers more accurate transduction, but puts a greater strain on the tonearm regarding tracking. Kept a little longer, the transduction is less accurate, but the tonearm has an easier time. I personally keep the suspension wire as short as I can, in the full awareness that some tonearms may have difficulties with my cartridge designs as a result. Other designers that I have talked to prefer to keep the free length of the suspension wire a little longer, for better compatibility with a wider range of tonearms.
>Miyajima and (I think) ZYX are two other makers who have incorporated this idea as well, although using different methods to achieve it.
Miyajima appears to be using a suspension concept similar to the old Glanz designs (check out US patent 27437). ZYX seems quite orthodox to me, and there is nothing wrong with that.
hth, jonathan carr