Emission Labs has a more suitable tube for that power , the 1605. Ayon uses a more powerful variant, what they call the 62b and even an 82b, which can make 30 and 35 watts, respectively. I had a 1605 based amp once that was rated at 24 watts and an Ayon Crossfire III rated at 30 watts and a Horning amp with 520b rated at 18 watts…so far I think this NEM might be the best sounding amp I have heard with this output tube family.If you squeeze the 520b properly, it produces almost the same power as an 845 tube, around 24 watts class a1. But that gets expensive in the long run; a pair like that costs €1.1k.