Hello, I've been using a Tech21 Sansamp PSA-1 in front of a Fender Bassman 400 (not the 400 Pro). I really like the SVT sound I get from the PSA-1. I've been thinking about upgrading my Bassman to a Mesa Boogie Big Block 750 because I love the creamy tubiness I heard coming out of it at the store and for the additional power and ability to run at 2 ohms. I would probably stop using the PSA-1, as I understand that some people feel it doesn't really "get along" with tube driven amps or sections of amps or even tube-driven pedals and because I'm just not sure I would want to keep using it, but I'm wondering if anyone out there has used these two together with either good or bad results. Please share thoughts and opinions - good and bad. Thank you.