four solutions in my mind:
1 - different OD... something with a little more bass cut. I found the Maxon OD808 and the Fulltone OCD to not only get the preamp more compressed (which will tighten in itself) but also it cut a little more bass than other ODs.
2 - a different cab. You might try the Stiletto 4x12 or even better, a Mills Acoustics 4x12. The Mills can handle any amount of bass you throw at it and basically retains clarity while adding power to your sound. I run the bass on channel 4 modern at about 3 oclock which i could never do with any other cab
3 - better preamp tubes. Its the most overlooked solution because as rewarding as it can be, it can be frustrating and expensive. In the roadster if you focus on V1, V2 and V3, get the right tubes in there, you can kill flub and fizz in one fell swoop. V1 and V2 dictate the highs, mids, headroom and harmonic characteristics. Once you lock those in to your liking you can play with V3 which dictates the character and amount of bass on tap.
I tried all of the above and I can get just about any tone i want. I used to use an eq in the loop to tighten things up but by going down route #3, i had no need for it anymore. Add in a cab that is basically flub-proof and the right OD, and its pure heaven.
4 - At the end of the day, the Roadster just might not be the amp for you. If your looking for Marshall liek tightness but with a tone that has more ballz, the Stiletto is what you should look at.
