One of many ramen establishments in Little Tokyo (in downtown Los Angeles) is Mr. Ramen. It sits a few doors down from the famous tonkotsu restaurant.
I have been coming to Mr. Ramen for years. The soup does not disappoint, but don’t expect tonkotsu soup base. They specialize in soy sauce or salt soup base. They serve the noodle soup in a large bowl with your choice of toppings. They have wide range of toppings from seaweed, fried chicken, pork belly, and more!