I missed this thread earlier in the year when it was more current but Spirit's latest message revives it, so I'll add a few comments I would have offered earlier.
I worked with Sean Casey and Adam DeCaria on the Zu103 project. In fact, they "discovered" the Denon DL103 in my living room back in 2005 when they visited to install a mod in my first Zu Definitions (v1.5). By that time, I had already been using the DL103 in one form or another for over 30 years, alongside a variety of other cartridges over the years. Being physics-minded, Sean and Adam had two immediate reactions to the Denon 103 (they were listening to a 103D at the time): 1/ music sounded tonally vivid and holistic, and 2/ "What's the deal with that lossy plastic body?" That started a conversation that became an on-again/off-again investigation that became an experiement and then a prototyping project and finally a product Zu chose to produce. My involvement was informal and "donated," as I just wanted a better 103. Zu did the hard work, with me as Alpha tester and field guide.
The entire focus of the Zu103 project was to repackage the cartridge to avoid wasting the energy and information the 103 motor was extracting from the moving groove. Everything was examined, from improving the rigidity of the mounting scheme to damping the motor assembly, and a variety of materials and dimensions were trialed. The result was a cartridge that retains the essential 103 characteristics of holistic tone, dynamic realism and excellent spatial projection, while elevating what's good considerably beyond the stock cartridge and sharply reducing its liabilities. This is another way of saying that a careful listener will hear the Denon DL103 through the Zu103, but someone who only knows the Denon 103 in stock form is likely to underestimate the Zu103. The Zu103 does exactly what Sean and Adam intended: without any change to the cantilever, diamond or suspension, the Zu103 yields a 103 that tracks clearly more intricately (makes a 103 conical stylus sound more like the 103D's elliptical), gains speed and dynamic impact, and levels the octave-to-octave balance with more extension up and down. Bass quality is also cleaner, deeper and more articulate. It is a 103 in another league yet still forgiving as the original.
I mention this all because anyone using this cartridge who is contemplating a stylus/cantilever "upgrade" should know that what they get back will sound substantially different from the Zu103 sent for modification. I'll go so far as to say that your Zu103 with a ruby/OCR (or line contact) cant/stylus will never sound like a Denon or Zu103 again. Whether you think it is better or worse will depend on your preferences and sonic priorities.
The Denon 103 dates to 1962 and was initially intended as a broadcast cartridge, not for consumer use. It found a following among hifi listeners and for good reason. Denon itself has issued many variants to the original plastic-bodied/aluminum cantilever/conical diamond 103. I have, for example, DL103, 103D, 103S, 103SL, 103FL, 103M, 103R, 103GL and have had a few others in the past. They are all different, and except for the uniquely deviant 103M, generally each includes just one significant upgrade from the original, plus a few more minor refinements. Generally, however, I have to say that the organic sound of the 103 is very much related to the robust aluminum cantilever and the conical or not-very-eccentric elliptical stylus shapes. If you change your Denon 103 or 103-based cartridge to a ruby, beryllium, quartz, diamond or other cantilever material, it is going to sound somewhere from "huh, that's different..." to radically different. What it's not going to sound like is a 103 just more so. And a highly eccentric stylus shape is going to widen the delta between what it was and what you get back.
I just went through a variation of this some days ago with a local friend who asked for my help. His turntable had been out of commission for a short while and he had his Denon DL103SA upgraded to a ruby cantilever with line contact stylus but he didn't tell me that initially. His exact complaint: "I'm just not getting the sound I used to from my Denon 103. What am I doing wrong?"
I drove over for a look and listen and immediately could hear why he wasn't pleased. I checked his setup and his signal chain (103SA into Cinemag 3440A SUT into phono section of his Cary KT88 integrated). All was as it should be. I removed the headshell from the tonearm for close inspection of the cartridge and it was only then that I saw the red cantilever. The story came out and no amount of fiddling would ever make that 103SA sound like a Denon 103 again. Now, it's a fleet tracker and it has sharper top end. But it also sounds more like a good CD player and it's completely unforgiving of aged LPs. The cartridge gained articulation, agility and speed, but it lost tonal realism, holistic spatiality, human presence and grace. BTW, I also have a spare SPU Meister Silver that a prior owner had sent to Soundsmith for a Ruby cantilever/eccentric stylus upgrade. I bought it specifically to lean more about how the change affects the SPU. It's also now a different animal, like my friend's 103SA.
It turned out he had a DL103R in stock form. Installing that in the right headshell restored his musical equilibrium and then we dug into the box of SPUs and Zu103 I brought with me. Now I can understand someone acquiring the upgrades to a 103 and liking the outcome, but it will be because you made it more like a Lyra or Sumiko than a better Denon. If you must replace a Denon 103's cantilever and stylus and want to retain its musical 103 essence, replace aluminum with aluminum, and don't go any more eccentric on the stylus than simple elliptical. That's my advice, anyway. The aluminum cantilever is part of the voice.
All of the disagreements expressed above about the Soundsmith Strain Guage sound very familiar to me because they are almost exactly the range of things people said about Sao Win's strain guage cartridge 30 or so years ago. I've heard the Soundsmith and it is undeniably vivid and excellent. On some systems it may sound lean or ascetic but it will invariably excel at presence and articulation, and prove exceedingly competent in extracting minute detail from the groove. The strain guage cartridge and electronics are a closed system so you're in for the whole shebang. It isn't inexpensive but it can be a revelation depending on what qualities you appreciate most.
Other than the obvious Koetsu vector as more expensive departure from Denon 103, I encourage consideration of the excellent and under-rated 47 Labs MC Bee, and exploration of Ortofon's SPU line. Yeah SPUs are even older than Denon 103 and you're not putting it in a Rega. But nothing in phonodom has the presence, weight, tonal heft, dynamic vividness and intrinsic emotion of the SPU. You need the right tonearm. It isn't the fleetest tracker nor is there anything analytical or "neutral" about SPU. If can be intensely intimate when music calls for it, or swell to bombastic scale when appropriate. It's more articulate than you expect it will be, used in an appropriate mass tonearm with great bearings ala the Thomas Schick. Most of the time I encounter DL103 or Zu103 devotees wanting the next step, it's an Ortofon SPU Synergy or Meister Silver that makes them more ecstatic still. For context, right now I am using five tonearms on three turntables with seven cartridges in stable: Ortofon SPU Synergy, Ortofon SPU Meister Silver, Zu103, Denon 103D, Denon 103FL, Denon 103M, Signet TK10LC (MM).
Most new design cartridges push vinyl to sound more like CD. There are exceptions, of course but you have to decide for yourself whether you want that. Of course if you're buying new vinyl of new releases you're usually getting a digital recording sometimes remastered for vinyl, so perhaps a CD-sounding cartridge is appropriate. The Soundsmith Strain Guage is not among them. It's its own thing, able to convey classic analog attributes without the sloppiness of exceesively romantic cartridges while being modern in speed & agility -- with energetic presence. It can be a tone monster on a great recording but often it's not. And it's not forgiving. If you have a chance you should hear it. I haven't needed Soundsmith's services yet (though I surely will at some time) but I have seen Peter's work and it is of high craft indeed. I hold Soundsmith in the highest regard for pushing analog vinyl playback into stratospheric levels of refinement. But sometimes their basic options are going to be the option than returns the cartridge you want.
Phil
