Cartridge incompatibility, Soundsmith and Luxman

@lewm Greatly appreciate your knowledge and input!!! In theory, it should work, but it's clearly rolled off (quite a bit...). The only logical answer I can see is the mismatch in loading. Gain should indeed be no issue. And I do really love the Zephyr Star, so I want to make it work if at all possible.

It seems like the options are either modify the Luxman or get an SUT... since I can only imagine is going to be pretty close to a wash cost-wise, I might just as well accept that I will need to go down the route of an SUT..

So with that said, any recommendations for a SUT? Don't want to break the bank (let's try to keep it less than $1k used), but sound is much more important than cost, so if that's the path...

Also, no experience with SUT's, I assume I should use phono cables out of it into the MM, but not just "regular" interconnects. Is this assuming correct?

I looked at the specs for both the Zephyr Star and the Luxman 590. There is no obvious reason why this pairing cannot be made to work well. First, I don’t understand quite why SoundSmith recommends a 470 ohm load for this cartridge. It’s internal DC resistance is only 10 ohms, so in theory it should be able to drive the 100-ohm load of the Luxman MC input stage. The problem might be that this is not actually an MC cartridge; therefore it has an inductance much higher than that of a typical MC. (About 100X higher, if a typical LOMC cartridge has an inductance of about 25uH. Inductance of Zephyr is 2.75mH.) Maybe Atma can comment on how that would be an impediment, but perhaps that is also why SS recommends a 470 ohm load. We also know from specs that the output of the Zephyr (0.4mV) is not too low for the MC inputs to handle, because Luxman tells us that the MC gain (NOT stated on the Luxman website but can be calculated) is adequate for a cartridge with an 0.3mV output. Before doing the research, I had assumed that the MC gain of the Luxman is derived from using a SUT placed ahead of the MM stage, but the website, while very lacking in phono-related info, suggests that MC gain is done by an active stage. For one thing, in their many photos, I see nothing on the PCBs that looks like a SUT. OK, so if there is no SUT, then there is no problem to replace the 100 ohm load resistor with a 470 ohm load resistor. Any skilled technician can do that. I would do that way before throwing either baby out with the bathwater. I am a big fan of MI or "fixed coil" cartridges.

Oh, by the way, this problem cannot be fixed by paralleling an external resistor with the 100-ohm input resistor, net parallel resistance is always lower than the value of any one resistor in the bundle.  So paralleling an external resistor can only lower the net input resistance, not increase it.

Per Raul, get some in-line RCA resistors to try.

I can't recommend a particular cartridge but the right outboard phono preamp will give you the adjustments you need to keep your current cartridge or any future cartridge. Perhaps a high output MC will work better for you. Personally I would not have a low output MC without an outboard phono preamp. Talk to your dealer or the manufacturer about matching a cartridge to your amp. 

Dea @audiojan  :  I think that before you pull the trigger for a different cartridge put in contact with Luxman and ask if exist a posibility that they can change the impedance to 400-500 ohms. You can try and maybe find out the solution.

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

Yes, MC setting. The load is not variable however, I think this is what's causing the issue.

Based on all I've read, I think you are correct.

@atmasphere Yes, MC setting. The load is not variable however, I think this is what's causing the issue.

@russ69 Which then means yet another piece of equipment, another set of phono cables (Cardas Clear Beyond sounds amazing, but they're not inexpensive...). Completely defeats the purpose of going with an integrated to simplify things...

Just get a Puffin and don't look back. It is adjustable to any and all carts.

but I'm not going to add SUT with additional cables and all that complexity.

It's the best option and makes your system future proof. It's not that complex and you can stash the preamp anywhere. 

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.

@audiojan 

Are you using the 'MC' setting on the front panel of the Luxman?