I cannot help you for tubes choice, i drive them with the tubes sold with it. I bought some tubes from Ukraine 1 year ago but i did not change them in the Douk yet...
I bought the Douk T8 pro and i like it....I need it to drive as pre-amp my self powered Edifier speaker...In my acoustic small room in nearfield i forget about any upgrade...
It is probably the best piece of gear we can buy for a low price with some Chinese Schumann generators...Name an equalizer with no evident limitation at this price point?
I will wait for someone who will chimes in with a tube proposal ... ![]()

