Even though I have the dream rig with the Helix, JTV89F and stereo 112 plus PowerCabs, the only thing lacking in my sound are tubes in the amp. I do have a DT25. It sounds great. Your best amp by far. Which makes me wonder why you didn't keep going in that direction. However, I have an older one and it doesn't play nice with the DT25/50 remote template on the Helix. I'm running the latest Helix firmware 3.5 and I've even used Line Monkey to update the DT25 to its latest firmware version. Yet, after doing that, I still have no controls from the Helix concerning the topology, the tube and class type switching. Basically, the only thing I can do is run a 1/4" cable from the ext amp out into the foot switch input to change between channel A & B. I get some humming on channel B when going directly into the front of the amp input from the line out on the Helix, and that's even with a noise gate in my signal chain. Channel A sounds great. I've tried the 4 cable method utilizing FX loop, but I get some reverb weirdness and extra artifacts noise when changing snapshots with high gain channel B settings, especially when trails are on. In spite of all that, the tube sound is awesome. Even though I really like the PowerCabs and that "in the room feel" on most of the stuff I program, the overtone presence is not there like it is with a tube amp, and the overall sound gets very squashy in live settings when I need to push the amp. It winds up not cutting through as much in the mix. The best solution would be a tube PowerCab!!! Then I could have all of the wonderful benefits of all the programming options, plus that great tube sound! There's no reason why you developers can't offer us the best of both worlds, so we don't have to settle for less than that perfect sound when tubes are in the amp. I'm pretty sure I'm not the only one who feels this way. Thanks for your time and attention, and, hopefully, this is worthy of your consideration. Take care!
Gary L