I had ...@dsper It looks like your journey is never ending, like most of us.
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Your Jolida phono pre should be more than adequate to reveal the wonderful sound AT150mlx would produce. You might still want to check the tubes.
I have not heard of MC AT150MLA cartridge. Are you sure about the model number?
If I were you, I would buy another brand new cartridge and test the overall setup. Any cartridge at over $100 should sound much better than CDs. Shure M97xE may be good. Gee M97xE was about $100 a few years ago, but now it sells at over $300.
If the sound is still dull or bass is thin, you might want to borrow your friend's turntable and give a try.
Anyway, there is no such thing as a perfect setup. You can only improve from what you have. The process of improvement is a fun part of listening to vinyl. Often times you get frustrated but it is just a part of the game.