My amp has 4 x 6SN7 & 4 X KT88's; right rear valve displayed most beautiful arking & blew main fuse. Replaced all Chinese valves ( & fuse ) with 'Top-end' ElectroHarmonix valves. Right front valve does the same trick, switch off before Armegedon arrives. I posted this "sorrow" on this forum & thanks for all the input received. I imported this amp directly from China, so no dealer support in South Africa,( only crime & indifference to Zimbabwe). I have seen these amps on the 'PACIFIC CREEK' website selling at exhorbitant prices. Found a LOCAL YOKEL who builds & repairs valve guitar amps - low & behold, he could not fault the amp, faulty valves - Chinese valve went BANZAI & new ELECTROHARMONIX also faulty. He fitted the amp with some USED Chinese valves & after a week phoned me to collect it. (At a price, which I gladly payed). He's impressed with the amp, played it for a week before he phoned me. No more branded valves for me - if it fits, it works.