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

@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?

When you use a SUT you should use short, low capacitance cables. Under 1m for sure, ideally 0.5m or as short as you can go. It has to be low capacitance - for example, the Audioquest LP / phono cables, and their Bridges / Falls IC cables are good, but their higher end Elements interconnects are BAD for this. Cardas interconnects typically have extremely low capacitance and are good for this.

I’ve done the 10x SUT thing for a Benz LPS with 0.34mV and 470 ohms MINIMUM recommended load (it seems like it wants a higher number), not too unlike your SS but MC based. Tried a few SUTs, 8x - 10x. It was an OK result, not stellar. I feel like this kind of cart is a tough match to a SUT (all my other carts love a SUT). With the LPS, I got a slightly better result from a Hagerman Piccolo2 which is a JFET headamp that has amazing gain & loading options and only costs $289. But the best result I’ve gotten from the LPS so far is on a Hagerman Trumpet MC, which only costs $1100 new and has an improved balanced Piccolo built in. The MM stage is tube based and (mostly) balanced circuitry. It’s not as quiet and refined as my VAC phono stage (which is SUT based), and the chassis & wall wart are clearly built to its low price point, but for that tough-match LPS it gave a better result than the ~$16K of phono stage & SUT.

The resistor mod to you Luxman sounds like it might be a great idea though.

Dear @audiojan : " need to go down the route of an SUT. "

Well, due to what you have in the Luxman that’s the bad move ( is up to you. ) that degrades the higher the cartridge signal against a " simple " internal modification below Luxman advise. Maybe I have to say SUT is the wrong way to go for the quality level of the cartridge you own, can’t benefit you in anyway but the other way around but as I said: is up to you.

 

" 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.  "

 

R.

Purchasing I rather inexpensive dedicated capacitance meter 

with zeroing lead capability can be quite handy for confirming

cable suitability.

@audiojan You might want to take a look at this website

http://hagtech.com/loading

Since your cartridge is a low output, scroll down to where the low output calculator is.

I dropped the values of your cartridge (2.75mH) and input load (0.1KOhms or 100 Ohms) and it spits out a rolloff value of only about 5KHz. That might sound rolled off 🙂

So you either need a different cartridge or modify the input load to be something higher. I put in the the 470 Ohm value as recommended and the rolloff changes to 27KHz!

So I think we found the problem.