Tube rollers may play with different brands of tubes and different types of permissible tubes like 6L6 / KT77 etc from EH,Gold Lion,Valve Art etc till they find the right tone

I will leave out the musical examples ( such as the quite lovely and pure string tone it produces , or the fact that the bass is quick and quite quite good, something tube amps - like my mini watt , which for its price is a great little unit- suffer with usually) and simply say that this is not a 'coloring' or 'sweetening' amp

Warm and rich mid tone to die for