HI i have a rocktron silver dragon and i play hard rock,80heavy metal,so mostly old school
i always loved that marshall jcm 800 sound i would love to have it through my s.dragon
so can you tell me with which tube should i replace the chinese stock tube to get that hard rock sound
Use the same tubes which the jcm800 has would be a good idea. Try groove tubes. they are known for making good tubes.