At the moment I'm using a Thunderchief as an outboard preamp with a TW Mosvalve power amp. Drives it with no problem all by its lonesome. Put a booster or OD in front, and it becomes a monster. I've done the same with the ROG 18, even the Fetzer, and will soon have the English Channel up and running for the same purpose. I wonder about those who have problems with ROG circuits not being loud enough. I'm guessing the problem is with the way they try to use them (as stand-alone amps maybe?), or problems with their gear.