I'm going to be getting a Tubescreamer soon to boost my 6505+ combo. I tried a regular TS-9 and was very impressed, but I'm wondering if the extra adjustment of the DX will be useful or a waste. I will only be using this as a boost to tighten up the sound, with the gain at zero and the level all the way up.
If you just want to tighten it up the TS-9 will do just fine imo. You wouldn't be using, or needing the extras
WTLTL 2011
The only extra mode on the DX that really sounds different (to my ears at least) is the Turbo mode and it makes your amp loud as f**k and adds a ton of gain. If you're just using it to boost and tighten your amp's dirt channel, the TS9 (or even a TS7 if you can find one) would work perfectly.