BunBakeI find the stock tube (the EH) gives some bloat in the mid-bass, but it's slight. I've tried a number of different tubes in this, some of them made the bass better but other areas worse, even my reference tube wasn't perfect in the T1. I think the EH is probably one of the best sounding tube for this DAC, you'll be very happy just to stick with it.
BunBakeStock tube is perfectly fine. I might try a few other tubes myself just to see what changes, but this is a situation where stock is actually quite good.