, the drive channels still sound cr@p for rock rhythm unless boosted.. I can get a much better vintagey/low gain tone using a TS7 boosting the clean channel when the volumes around 3 8)
3 is far too low a setting - your amp is only just starting to wake up - and you're right about the drive channel. My tip would be to ignore it and treat your amp as single channel until you've discovered what it can do. Now that you've got your attenuator try the following (if you havn't done so already):
Take your pedals, put them back in the boxes they came in and store them somewhere safe (you may want to sell them later),
Plug your guitar straight into the amp,
Select the clean channel and turn the volume up FULL,
Fiddle with the guitar's volume control(s) to get different tones,
(I was listening to How The West Was Won the other day and you can hear Jimmy Page using this technique to good effect),
Bring the amp's volume back a touch if you like - I usually have it around 8 - 9.
