I use an AM V but with my preferred Cardas loom and also use AT MC's (AT33EV and OC9/II) and have no issue with missing bass.
Maybe the bass is there but the silver litz loom is emphasising the top end a bit and making you feel it is missing a little from the overall balance ?
Use of the provided head shell weights can be useful with some carts though - I also have a Dynovector Karet which is very light but I prefer to remove weight from the back rather than risk too much weight on the short Diamond cantilever this cart uses. Now this cart really does dig the bass out with the AM V and at a hell of a speed - it can be frightening when a significant drum session starts !
Mel