Built a Tubelab SE (TSE) amp using type 45 DHT out tubes, Electra Print output tranny and Edcor power tranny.
So from the tubelab page, you can see that it can support 300b, 2A3, 45 and other output tubes. I actually started to build a 300b amp, but then
The TSE is configurable, and supports a variety of DHT output tubes, so you have to pick which one you want to use
When I started this project years ago, I wanted to use both 300b and 45 tubes. But I shelved the project because it became too complicated, and I was having trouble implementing everything I wanted.
After I resurrected the project, I scaled back from the original plans, and decided to use 45 DHT's.
Few reasons. 45's have a great audio reputation, main drawback is lack of power. Power for a headphone amp not really a problem. 45's are relatively cheap, at least compared to 300b and 2a3's. And probably the biggest reason is I had a pair of 45's I picked up when I started this project.