Cartridge incompatibility, Soundsmith and Luxman


I have a Soundsmith Zephyr MIMC Star cartridge that sound really amazing, but I just changed to a Luxman L-590AXII and the gain and loading is fixed.

Output/loading for cartridge: 0.4mV, recommended load resistance 470 ohm

Input sensitivity/impedence for the amp: 0.3mV, 100 ohm

 

The gain should be ok, but the load is way off and you can clearly hear it. The highs are rolled off and I need to crank up the volume to be acceptable level.

 

So here's the question... what cartridge would work in this setup? Would love to keep the Soundsmith, but I'm not going to add SUT with additional cables and all that complexity.

128x128audiojan

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.

Larry, If you read the responses, you will know that the problem is almost certainly the fact that the fixed value of the load resistance at the phono inputs of the Luxman is 100 ohms.  The Zephyr is a rare low output MI type, which has high inductance compared to a typical LOMC type.  Thus it needs a higher value load resistor.  The high inductance cartridge into a 100 ohm load would be expected to exhibit all the characteristics that the OP is not happy with, and justifiably so. That issue would have to be dealt with before one could fairly evaluate other elements in this system.

First, I'm not going to open up the amp and modify it. By the time I do that, I might just as well spend the money to get a different cartridge. Yes, I do like the Zephyr, but there are other good ones out there.

 

Larry, yes, I do love the sound of the 590axii. It's ONLY the phono that sounds extremely dark. Switching to a different cartridge (I have a spare MM cartridge) opens up the highs to be just like my streamer (or CD for that matter). It's a compatibility issue between the fixed load and the cartridge.

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.  

Larry, The low output Zephyr already has a low internal DCR of 10 ohms.  That's not the problem.  The problem is its inductance, which, at 2.5mH, is about mid way between a typical LOMC (about 50 microhenries) and a typical MM (500 millihenries, or about 10,000X more than the LOMC).  If the Luxman was mine, it would have been "modified" last week. I don't really view this as a modification in the usual sense that we use it, because the change does not alter the circuit or alter ("upgrade") the parts content.  I'm envious of your Orpheus, BTW.

audiojan, I realize the die is cast, but to say you "might as well spend the money to get a different cartridge" indicates money is not an object. Because changing the resistor, even if you must hire someone else with the expertise to do it, is bound to be the less expensive alternative.  Anyway, your problem is solved one way or the other.