Cartridge incompatibility, Soundsmith and Luxman

How does the Luxman sound when playing other sources, such as CD player or streamer, as compared to your prior rig?  It would help to know if the basic sound of the Luxman is to your liking.  If you like the sound, then it is the phono stage that is an issue (either not very good, or incompatible with your particular cartridge or other aspects of your set up).  How much have you experimented with other aspects of your phono setup--have you played around with VTA, for example?  A higher VTA (pivot of tonearm elevated more) will tend to shift the tonal balance more toward the high end.

I have read the responses, and in fact, I suggested a cartridge with a source impedance below 10 ohms, in acknowledgment that that might be a way to avoid the incompatibility problem.  I just wanted to be sure that the OP did not get off on the wrong track.

I hesitate to offer specific recommendations because cartridge preference and system matching is so personal.  If I were to hazard a guess, a Lyra cartridge might be a good match--most have quite extended highs, a very clear sound, and have a fairly low source impedance that would be compatible with the 100 ohm loading of the phono stage.  I own an old Lyra Titan and I like its sound, although these days I run a Transfiguration Orpheus L.  

Yes, I agree completely.  I made the recommendation for low impedance cartridge because I thought the OP is set on finding a MC replacement for the Zephyr and I was trying to suggest staying with low impedance cartridges to avoid the same sort of loading issues.  
 

I think am guessing that the $1,000 comes from the amount you are willing to spend on a SUT, such that paying for a modification would have to be at or above that amount to be out of the running as an alternative.  Most repair places will charge for the modification by the hour, with one hour at a minimum.  I would expect that one hour’s labor would be charged, and the lowest charge I would guess is $120 per hour.  I would guess $160 per hour is more realistic, so expect $180 as the total cost. For future versatility, you should consider a very high value resistor (meaning LOW loading), with the use of loading plugs to set the particular value for your cartridge; that might mean paying the technician make loading plugs. The ideal approach would be having cheap plugs of various values (e.g. 80, 160, 320, 1,000), and after ascertaining the correct value, I would hard wire a quality resistor between the positive and ground of the back of the input jack (easy to do and safer than desoldering the resistor on a circuit board which may accidentally damage a trace).

The SUT approach would require not only the SUT, but also a decent interconnect (shielded interconnect to minimize noise pickup).  This is an expensive approach and you run some risk of noise problems that are hard to resolve by finding the right location of the SUT, but, I personally like the sound of them.

Would the quality of the resistor matter differently if the loading resistor is a voltage divider in parallel with the signal from the cartridge vs. the loading resistor being a shunt to ground?

If you cannot find a technician to switch out the built in loading resistor (assuming this IS the issue), and you are against using an external SUT feeding the MM input, you will be in the still troublesome spot of finding a cartridge that works.  Do you have a dealer that is willing to allow you to audition cartridges or allow you to bring in your integrated amplifier to see if sounds okay with particular cartridges the dealer has to offer? 

I would hate to hazard a guess as to which cartridges might be compatible, not only with your integrated, but with the rest of your system and your particular taste.  The 100 ohm fixed load suggests a cartridge with a low impedance of the coils in the cartridge itself-at most an impedance of 10 ohms, and much lower would be better still.