Sounds very interesting Lowboy. I have struggled for a long time with my amp set up. I recently usused a Summit Audio TD 100 tube preamp DI box for my Hammond melodions to boost up the volume and to warm up the sound live. Lucky enought that I was able to borrow one than to buy it first. The unit work great but it is not ment for microphone low impedance. I am going to save a little more and pick up the universal Audion 610 tube DI preamp made for both so I can use it for both live and studio work. I have been using my Traynor K4 keyboard amp as a stage monitor but really hate lugging it around. I also use a Fender Acoustasonic Jr amp but does not have enough power to use it as a decent monitor. I may have to build a small Tri-Amp system that would hopefully give me the sound. I need before it goes out to the main system. And hopefully I will be able to make it small enough to carry easily. What tube amp were you thinking if using.