Changing the phono load resistors is neither a mod nor a tweak in my book. But why do you hold the opinion it shouldn’t be done?
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.
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- 60 posts total
Finding that load resister is not hard. It will be right off the phono input @retipper has already joined this conversation and is obviously loath to give himself business by making this suggestion but, I would suggest acting as an obvious shill for Soundsmith that you send him your amp and he will be happy to make that modification and sell you some loading plugs for a very reasonable cost. |
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. |
- 60 posts total