MM or MI Cartridge?

Soundsmith makes a strain-gauge cartridge. This type does not use an RIAA network/phono stage. It does the equalization mechanically. It can drive a line stage - eliminating the phono stage. I listened to the Panasonic strain gauge at a friend's house. It fed the line stage of a Marantz 7 tube preamp into a pair of Futterman H3aa OTL amps into Quad 57's. I was impressed! Soundsmith claims their strain gauge cartridge is a superior improvement over the Panasonic.

Jason, kudos to your friend with the Marantz-Futterman-Quad system. That’s a vintage combination to rival many modern high end systems except it needs a subwoofer. Back in the early 70s, I owned a similar system save for using KLH9s, first one pair and eventually two pairs, in lieu of the Quads.

The Nagaoka MP-500 is the closest sounding cartridge to my London Decca Reference. I have bought a couple of spare styli for it, plus a tonearm to mount it on. It's that good, and clearly beats the Grado Statement 3 and the SoundSmith Sussurro MkII. I do run a table with two MC cartridges (Ortofon Cadenza Bronze and Mono) as well, but they come behind the MP-500 for musicality.

The big difference between MC/MI/and MM cartridges boils down to a very few factors, most notably stylus profile, of which much ink has been spilled, and inductance, which is rarely mentioned. Moving coil carts have the lowest, then Moving Iron, and then Moving Magnet. why does this matter? Inductance directly relates to a property called hysteresis, the delay between a change in input and a change in output. Google 'hysteresis curve' and you'll see the characteristic 'S' shaped hysteresis curve, and its return, the hysteresis loop. Ultra low output MCs sound fast and detailed in large because they have low inductance, thus low hysteresis. MI carts like Grado and Soundsmith  have greater inductance, roughly in the 50mH range, but the difference is incremental. Most Moving Magnet carts have 10X more inductance around 450-550 mH and accordingly 10X more hysteresis, more delay between changes in input (stylus motion) and a change in output voltage. They simply cannot respond without 'smearing'. The tradeoff in general is output voltage, where MM carts win by a mile, thus making preamp design easier and more forgiving. This is why most MC carts require an additional level of gain, and usually worse S/N ratios. There are other factors, to be sure, vibration control, compliance, tracking ability, and several more but all of those can be controlled independently of the electromagnetic performance of the generator which is determined in large by the cartridge designers choice of MC, MI, or MM. I haven't gone into cartridge loading which is important, but cannot compensate for the hysteresis inherent in the design.

I have a Viv 9" as well, with the carbon fiber tube. The Royal N hasn't spent that much time on it, I'll have to give it another chance.

My favorite MM/MI's are all from the golden age of analog. The Denon 109D (with Jico stylus) is an exceptional all-around performer with a lot of punch. Technics 207C w/Jico SAS, Signet TK-7lca and Shelter 201 w/Jico SAS are also winners.