Tone arm upgrade

I agree with Jakeman. The Ittok is a wonderful arm, but so is your modded RB300. It would be a lateral move at best.

If your system page is up to date and you are currently using a Dynavector 10X5, which is a fine cartridge, but you can definitely do better.

Your SOTA table would be a great platform for a used SME 309 arm, if you really want a new arm. I sold lots of that combo back in the day and it's a fantastic set up. I would still get a better cartridge for either arm.

I moved from an upgraded RB300 to an Origin Live Encounter 3c and have been very pleased.

The RB300 is a very good tonearm. Your money will be better spent somewhere else in the chain. Get a decent tubed phono pre or a new cart, as Jake suggests.

I concur to Linn tonearm being much better vs. RB300.

I agree with those who say change the cartridge. Put a Lyra Dorian in there and you will be amazed at the difference. If you want to spend less, I recommend a Goldring Eroica. Very good cart for under a grand. That being said, I upgraded from a Rega 600 arm to a used Ekos and it was a big upgrade - as it should be for twice the price used and over 3x the new price. Contrary to what's said around here very often, sometimes the more expensive stuff IS better.